Tag Archives: food

Ways in which an eater can get negative calories from food

There are at least four ways in which an eater may have less energy and nutrients after consuming a food: mechanical, chemical, physical and biological. The mechanical way is that chewing and other parts of digestion take energy, so if a food requires serious mastication and contains few calories, then more energy may be spent than absorbed. This has been claimed for raw celery.
Chemically, one food may react with another in a way that makes one or both of them less digestible. The less effective absorption reduces the nutrients obtained compared to not eating the second reactant. The chemical pathway to inefficient digestion may have multiple steps. For example, ascorbic acid leaches calcium from the body, and calcium is required for the absorption of vitamin D, so eating more citrus fruits may indirectly reduce one’s vitamin D levels.
When calculating the calorie content of food, indigestible fibre is subtracted from carbohydrates before adding up the energy obtained from carbohydrates, fats and proteins. However, if fibre reduces the absorption of calories (in addition to its known reduction of the absorption iron, zinc, magnesium, calcium and phosphorus), then the food’s bioavailable calorie content is less than that obtained by simply subtracting the fibre. To derive the correct calorie content, the fibre should then have negative weight in the calculation, not zero. This difference may explain why in Western countries, a high-fibre diet predicts better health in multiple dimensions in large prospective studies (Nurses’ Health Study, Framingham Heart Study), controlling for calorie intake, lifestyle and many other factors. If the calorie absorption is overestimated for people eating lots of fibre (because the calorie intake is larger than the absorption), then their predicted health based on the too high calorie estimate is worse than their actual health. This is because most people in Western countries overeat, so eating less improves health outcomes. If the predicted health is underestimated, then the high-fibre group looks unusually healthy, which is attributed to the beneficial effects of fibre, but may actually be due to absorbing fewer calories.
A food may chemically break down tissues, e.g. bromelain and papain, from fresh pineapple and papaya respectively, denature meat proteins, so cause mouth sores. Rebuilding the damaged tissue requires the energy and nutrients, the quantity of which may exceed that absorbed from the food.
Chemically causing diarrhea reduces the time that foods (including the laxative agent) spend in the gut, thus reduces nutrient absorption.
Stimulants like caffeine speed up metabolism and cause greater energy expenditure, but may give zero calories themselves, resulting in a net negative caloric balance.
Just like chemical damage, physical injury to the body necessitates spending calories and nutrients for tissue repair. For example, scratchy food (phytoliths, bran) may cause many microscopic wounds to the digestive tract.
Cold food requires the body to spend energy on heating, so if the calorie content is small, then the net energy obtained is is negative. Examples are ice cubes and cold water.
A food substance may physically partially block the absorption of another, for example a gelling agent (methylcellulose, psyllium husks) may turn a juice into a gel in the gut and thereby reduce its absorption. Based on my personal experience, psyllium husks gel liquid feces, thus effectively reducing diarrhea. Mixing psyllium husks with carrot juice and with asparagus powder dissolved in water before consuming them during the same meal results in the excretion of separated faint orange and green gels somewhat distinct from the rest of the feces (photos available upon request, not posted to keep the blog family-friendly). This is suggestive evidence that the gelling agent both kept the juices from mixing in the gut and reduced the absorption of the colourful compounds by keeping the juice in the centre of the gel away from the intestinal wall.
Biologically, a food may reduce the nutrients available to the organism by causing infection, the immune response to which requires energy and depletes the body’s reserves of various substances. Infection may lead to diarrhea, although the mechanism is chemical, namely the toxins excreted by the microbes. Infection with helminths (intestinal worms) that suck blood through the wall of the gut requires the replenishment of blood cells, which uses up calories, protein and iron.
If the food takes a long time to chew or is bulky, then chemical and electrical signals of satiation are sent from the gastrointestinal tract to the the appetite centre of the brain. These signals reduce the desire to eat, thus decrease calorie intake.

Modernist cuisine notes

Vol 1 [page numbers from book]
p.8 Countries with a long and stable ruling class developed the most complex cuisines. Dinners as status symbols. Cold climate leads to low plant and animal diversity, providing less varied ingredients.
p.11 Silphion/silphium became extinct in 1st century AD due to overuse for making laserpicium, a seasoning in Roman cuisine. Another key ingredient was garum, a fermented fish sauce.
p.12 European cuisine in the Middle Ages was quite homogeneous. It used imported spices extensively. The most popular in savory dishes were cinnamon and ginger.
p.14 Pasta isn’t Italian – Arab traders introduced it to Muslim Sicily before Marco Polo. China had noodles 3000 years before Italy.
p.15 The most important sources of nutrition in Africa are cassava and maize, both from South America. Bananas are from Southeast Asia.
p.22 Fast food has been around for a long time as street food at open-air markets.
p.23 People have voted with their wallets for fast food and industrially produced food.
p.24 McDonald’s is the largest private-sector employer in France.
p.25 Plated dishes (brought to table on a separate plate for each person) were invented in the 1960s. Previously everything was “family-style.”
p.40 Sous vide cooking came from Swedish hospital food – cooked food packaged in plastic while hot to prevent spoiling.
p.44 Searing meat early in cooking causes it to leak more juices.
p.48 Cutting the head off a whole roasted pig after cooking keeps the skin crisp, because it allows steam trapped under skin to escape.
p.50 Listening to sea sounds while eating an oyster makes it taste stronger and saltier than usual.
p.110 Foodborne illness: invasive infection (pathogens penetrate gut wall), noninvasive infection (secrete toxins in the gut), food poisoning (secrete toxins into the food before it is eaten). Food poisoning creates symptoms faster because pathogens do not need time to replicate. Mortality from foodborne illnesses is low. Incidence is high – 25% of population per year.
p.115 Food is usually bought clean and contaminated by cooks. Foodborne illness spreads mostly via the fecal-oral route, due to poor hygiene.
p.118 Pathogens mostly contaminate the food surface and can contaminate any food – vegetables are not safer than meat.
p.123 Freezing fish at internal temperature -20C for 7 days or -35C for 15 hours is recommended by FDA for sushi in order to kill anisakid worms. Coldsmoking and drying do not kill tapeworms.
p.132 Most bacteria infecting humans are aerobic, because oxygen in blood kills anaerobic bacteria.
p.133 Spoilage bacteria causing rot in food are almost never pathogenic. But their presence signals the presence of other, pathogenic bacteria. Absence of spoilage does not mean food is safe.
p.138 To avoid bacteria growing from spores, food should be eaten quickly after it is thawed or cooked.
p.143 Most bacteria grow most rapidly slightly below the lethal temperature for them. Most pathogens cannot grow above 55C. Fastest growth of foodborne pathogens occurs at 37C-43C and pH 7.
p.148 Cold does not kill bacteria. Bacterial death depends on both time and temperature.
p.152 Viruses only replicate in living cells, so not in food.
p.157 Prions of mad cow disease survived the cremation of the cows. They also survive radiation, UV and strong acid.
p.168 If the food is not contaminated, eating it raw won’t hurt you. If it is heavily contaminated, very long cooking time is needed. Food safety is as strong as its weakest link, which is often cross-contamination.
p.196 80% of foodborne illness is caused by fecal contamination. Hand washing should be at least 30 seconds, thumbs and wrists should be included, as well as scrubbing under fingernails with a stiff brush. Use a paper towel for the faucet and doorknob.
p.197 Hands should be washed after every preparation step that could lead to cross-contamination, i.e. after handling any raw food.
p.205 Temperature in energy-efficient low-power refrigerators can remain high for hours after a warm dish is inserted. Minimize time of door being open. The temperature varies inside a refrigerator, especially in one without fans.
p.206 Even digital thermometers are accurate to only plus/minus 1.5C.
p.207 The most accurate thermometers are platinum RTD-s, but these are expensive and fragile. Oven temperature can be 5% off what the knob indicates.
p.213 Monosodium glutamate found harmless by all the many studies on it. It occurs naturally in e.g. cheese, tomatoes.
p.214 High fiber intake does not reduce risk of colon cancer. Neither does low-fat diet nor a diet high in fruit or vegetables.
p.218 Observation bias means the act of studying a person changes their behavior. Weight-loss intervention studies frequently overestimate the benefit of the proposed diet, because participants stick to the diet only as long as the scientists track their progress.
p.221 No link found between breast cancer and red meat consumption, or the way the meat was cooked.
p.222 Saturated fat means the carbon atoms are saturated with hydrogen and only single-bonded to other carbon atoms. Saturated fats are generally solid at room temperature, unsaturated fats liquid.
p.226 Cholesterol level in blood below 160 mg/dl increases mortality risk from accidents and violence. Link between cholesterol and heart disease is complicated. Small dense lipoprotein carrying cholesterol is associated with heart disease.
p.227 Statins lower men’s heart disease risk, but not women’s. Statins lower blood cholesterol in both.
p.229 Fat consumption can raise high- and low density lipoprotein levels in blood fast for some people (depends on genes). Eating less total fat or saturated fat for several years does not lower the incidence of heart disease, stroke or other cardiovascular diseases.
p.230 No evidence that dairy consumption increases cardiovascular disease. Red meat consumption does not increase risk of heart disease, diabetes or stroke, but processed meat seems to.
p.231 Margarine consumption is associated with higher heart disease.
p.234 Lower sodium (salt) consumption reduces blood pressure by a few percent. Chronic hypertension is associated with heart attacks, strokes, kidney disease.
p.235 Vitamin supplements have increased and decreased disease in different studies.
p.236 Highest-salt diet is associated with a higher risk of stroke.
p.237 Globally, 1-5% of the population have a food allergy (immune system reacting to food proteins). 90% of food allergy is to shellfish, fish, peanuts, cow’s milk, eggs, tree nuts, soybeans or wheat.
p.238 80% of people who think they have a food allergy actually have a food intolerance (mechanism causing symptoms is not an immune reaction, but something else).
p.245 If organic plants have higher levels of pests, they may produce more toxins to combat the pests. This may make them more toxic than pesticide-treated plants. Organic farmers may spray natural pesticides, e.g. nicotine, on their plants.
p.254 Newer additives are tested for safety, but older, e.g. sucrose, were allowed in food untested due to a Generally Recognized as Safe exception.
p.269 Precision of a thermometer means it gives the same number every time the same temperature is measured. Accuracy means the number is close to the true temperature.
p.274 The rating of an electrical applicance shows the maximum watts it draws from the power supply when operating, not the watts it delivers to the food.
p.279 For thin slices of food, a twice thicker slice takes approx. 4 times longer to cook or freeze.
p.283 Stirring disrupts the boundary layer – a thin layer of fluid stationary around the food that insulates it somewhat. Stirring air increases its heat transfer coefficient tenfold, that is why blowing on hot food cools it. Freezing in moving air is similarly faster.
p.284 As bread darkens in toasting, its rate of absorption of heat increases, so it slowly warms, but quickly burns.
p.284 A good griddle is shiny to reduce radiant heating of the kitchen while keeping the same conductive heating of the food.
p.286 Wood-fired ovens differ from electric ones not only due to higher temperature. Since radiant heat rises with the fourth power of temperature, radiation provides a greater fraction of heating in wood-fired ovens than convection. Electrics heat mostly by convection.
p.289 Coffee with cream cools 20% slower than black coffee, because whiter things emit less radiation, the fatty cream at the top slows evaporation, and the temperature difference between the coffee and air is smaller after cream is added.
p.294 A carrot is 88% water by weight, same as milk. A cucumber is 95% water, more than some mineral waters.
p.298 Hydrogen bonds between H in one water molecule and O in another cause the high surface tension, high freezing and boiling temperatures and high specific heat of water compared to other substances with similarly lightweight molecules. Hydrogen bonds form hexagonal lattices of water molecules in ice. The hollow spaces lower the density of ice to 92% of that of water.
p.305 Extracellular fluid has less dissolved substances than intracellular, so freezes first. As part of the fluid freezes, dissolved substances are concentrated in the rest, lowering its freezing point.
p.306 As part of the water in the food remains liquid due to dissolved substances, the growing ice crystals outside cells draw water out of cells, leaving them deflated. *This seems wrong, osmosis should move water in the direction of more dissolved substances, so into cells, not out.*
The ice damage to food stops below the glass transition temperature, between -20C and -80C. The water molecules will be not in a crystal, but in random fixed positions.
The oxidation of fats continues even at very low temperatures, so fatty foods become rancid.
p.309 Pressure-shift freezing cools food below its room-temperature freezing point at high pressure (water remains liquid), then releases the pressure to freeze the food to the core at the speed of sound.
p.310 A freezer is for holding frozen food, not freezing food. For freezing, a blast chiller, an ice brine, liquid nitrogen or dry ice are good. It is not good to freeze thick pieces of food quickly due to freeze-cracking – the inside when freezing expands, pressing the already frozen outside.
p.311 Thawing takes longer than freezing, because liquid water in the outer layer of the food conducts heat four times slower than ice.
p.313 Best to thaw quickly or cook from frozen. In large pieces of food, the small ice crystals melt first and can refreeze onto the larger ice crystals. Large pieces are best thawed in cold water in the fridge.
p.318 Dissolved substances raise the boiling point of water.
p.319 For vegetables, steaming is slower than boiling, because air forced out of the food by heat expansion forms insulating bubbles on the food surface. For food in smooth sous vide bags, steaming is faster than boiling, because droplets of water roll off the bag – no boundary layer. Steam does not dissolve substances and draw them out of the food, so the food retains more flavour.
p.320 Stale bread has absorbed moisture from the air, making the crust soggy and crystallizing starch in the interior. Heating the bread reverses both. The crystallization is faster at lower temperatures, e.g. in a fridge.
p.321 Relative humidity matters in cooking, because evaporation cools food. Vacuum pumps can cool cooked food quickly.
p.326 Water can sublimate from frozen food, drying it and allowing air to react with it (called freezer burn). The vapour can deposit on the walls of the freezer as ice.
p.333 Solids dissolve more easily in water at higher temperatures, gases less easily. Pressure increases gas solubility one for one at room conditions.
p.335 Hard water toughens some vegetables by reacting with pectin in plant cell walls. Hard water interferes with gelling and thickening.

Vol2
p.7 Grilling: increasing draft speeds burning, increases heat, but with a lag.
p.8 Food must be thin to be evenly grilled. Coals should be covered with ash before food goes on the grill. Flavour comes from burning drippings.
p.9 To avoid food sticking to the grill, preseason the grill with a patina, like a wok.
p.10 Cooking depends on the intensity of power, measured in W/m^2. The radiant heat matters most, not the hot air. Gas burns hotter than charcoal, but gas grills radiate less heat per area.
p.13 For thick foods, cover the grill, shift coals to one side and food to the other. A pan of water under the food humidifies the air, increases heat transfer and slows drying of the food.
p.14 To heat food evenly, the grill should have vertical sides, shiny interior, large diameter.
p.20 Food changes colour when cooked, which changes speed of radiant heat absorption. The rate of cooking changes, so darkening food gets burned suddenly.
p.21 Blowtorch uses convective heat transfer. The wind also dries the food. First warm up the torch, let the flame go blue, then point at food.
p.24 Simultaneous poaching and broiling: food in a bath of cold water or wine, top above the liquid. Heat from the top with a broiler, liquid warms slowly, top of the food crisps.
p.28 The time it takes to heat the centre of the food is inversely proportional to the square of its thickness. Bigger roasts should be further from the fire so they don’t burn before cooking through.
p.35 Rotating the roast distributes heat evenly. Enclosed oven raises the temperature compared to open fire, so surface and interior temperatures differ more.
p.38 Panfrying: flip food every 15-30 sec for faster and more even cooking.
p.41 To crisp duck skin without overcooking the meat, freeze the skin and a thin layer of fat beneath it before cooking (cryosear).
p.43 Burner should be the size of the pan. If not, bolt a sheet of aluminium under a thin steel pan to increase conduction speed and evenness.
p.44 Sauteing requires enough oil to conduct heat from pan to food surface. Use small pieces, coat them in oil before sautéing. Water leaking out of food lowers the temperature, prevents browning. Saute should start with a loud sizzle that gradually quiets as the surface of food dries.
p.48 Wok quality is its patina: non-stick layer of bonded fat and metal oxide. Wok cooks by conduction, condensation and convection. Heat is controlled by tossing food into the air.
p.52 Wok burner 60kW, 15-40 times domestic gas burner. Pan can reach 1200C.
p.63 Water at boil conducts heat 2-3 times faster than a few degrees cooler nonboiling water, due to turbulence.
p.66 Blanching in boiling water for a few seconds brightens colours of vegetables because the air gaps collapse and fill with water, so less light is absorbed.
p.70 Steaming cooks slower than boiling, because a layer of condensation water insulates the food from the steam. Also, air bubbles below the condensation insulate. Boiling dilutes the juices more than steaming, so more taste is preserved by steaming.
p.76 Boiling-water canning kills microbes and inactivates enzymes, works for acidic foods (pH<4.6). For other foods, pressure canning is needed. Put the lid on loosely, let steam push air out of the jar when canning, so that a vacuum forms under the lid when the jar cools. This pulls the lid tight.
p.85 Pasteurization uses lower temperature than canning to keep food flavourful, but pasteurized products may need refrigeration, since some microbes remain.
p.86 A canner’s pressure gauge measures the difference between pressure inside the canner and outside, not the absolute pressure. Pressure cookers do not have a pressure gauge and leave air in the headspace, so are not suitable for canning.
p.101 Baking was originally for drying mud bricks and food. Humidity is critical.
p.102 Preheating is important so the oven walls store heat and the temperature does not fall too much when the oven door is opened. Heat must pass through air in the oven to reach the walls, and air insulates. Air expands when heated, so most of the hot air leaves the oven.
p.103 Basting speeds cooking: putting hot oil on food transfers heat and insulates from evaporation. As long as the food surface has not dried, its temperature is below 100C. This wet-bulb temperature is lower than the dry-bulb one that the oven thermometer shows, and always below 100C. Wet-bulb temperature depends on air humidity.
p.109 For whole chicken with crispy skin without overcooking the meat, separate skin from meat first by pushing fingers under it. Then raise chicken above bottom of pot or oven so the skin does not soak in juices. Cook slowly 3-4 hours, then quickly brown the skin.
p.110 Convection ovens speed cooking, significantly for thin foods like bacon, because they disrupt the boundary layer of cool moist air above the food and speed drying.
p.111 Bigger batches of food may bake faster in the oven, because more water evaporates from more food, so the humidity rises, raising the wet-bulb temperature. Oven thermostats are often wrong. Calibrate yours.
p.112 Oven walls radiate heat unevenly, especially the door. Food may burn in some places, not cook in others. Keep oven clean, because grease stains burned black radiate more heat. Altitude means faster evaporation, less water vapour in the air, so food may be hotter or colder (surface dries faster and gets to boiling point sooner, but boiling point is lower).
p.116 Boiling in oil slows evaporation compared to baking. Preheat oil to 150-200C, this is the dry-bulb temperature. Vapour is trapped next to food, so wet-bulb is close to 100C. If vapour bubbles stop streaming from the food, then the surface has dried out.
p.117 Surface of food burns faster when boiled in oil than when baked, because oil conducts heat faster than air. Use small, evenly sized pieces of food.
p.122 Wet batter lowers the temperature of the food beneath and avoids overcooking delicate foods. Two-step deep-frying means cooking the food at a lower temperature first and then briefly at high temperature to brown the crust.
p.123 Oil changes with heat. Old oil should be changed, but new oil “broken in” by heating it with a small quantity of old oil. The surfactants produced with heat allow oil to get closer to food and cook it faster. Aromatic compounds also form.
p.124 Blue smoke above the oil is a sign that it is too hot or too old. Foaming or rancid-smelling oil is too old. Too many new compounds have formed with heat.
p.125 Oil enters food when it cools and the surface has dried out, so pores wick oil in. Blot the deep-fried food immediately after taking it out of the fryer. Blanching food before frying forms a crust and reduces oil absorption. Especially blanching in salty or 0.5% calcium chloride water. Overloading the fryer lowers the temperature and increases oil absorption.
p.126 Saturated oils last longer than unsaturated. Saturated has higher melting point. For food served cold (potato chips), unsaturated is used for the surface fat to melt in the mouth.
p.129 Instead of cooking confit in rendered fat, one can cook sous vide and coat it in fat later.
p.134 Smoking releases aromatic compounds from lignin in wood breaking down at over 300C. These compounds soak into the food and give it the smoked taste.
p.135 Use dry wood for smoking. Green wood produces fog from steam emitted when heated, which looks like smoke but does not give the right flavour. Low-temperature smoke is acidic. Best temperature for smoke production is 400C. Flames make it too hot, 1000C.
p.138 Control the airflow in the smoker to control which compounds are produced and prevent bursting into flame. Control humidity so the food is not too wet or dry and the compounds diffuse inside instead of dripping off.
p.148 Cook sous vide, then dry in the oven until the surface is tacky, then smoke.
p.158 Water baths and CVap ovens take a long time to reach the target temperature, because water heats slowly.
p.167 Combi ovens reach the target temperature in 5-10 min, but below 60C the temperature accuracy is low.
p.171 Sausages are sometimes fermented at 30-50C.
p.182 Microwave ovens operate at 2.45 GHz, same as wifi. Water vapour in the atmosphere limits the signal radius. Microwaves only penetrate 1-2 cm into the food. The rapidly varying electric field of the oven vibrates the polar water molecules. Fats and oils are also heated by microwaves despite being nonpolar.
p.183 The holes in the metal of the microwave oven door are much smaller than the microwave wavelength (122 mm), so do not let energy through. Due to the long wavelength, the diffraction pattern may heat the food unevenly. Large food items heat faster than small.
p.189 Microwaves are good for drying food.
p.201 Sous vide reduces oxygen damage to food and allows good temperature control. Air in the sous vide bag insulates the food, slowing cooking.
p.213 Vacuum packing with low pressures damages food because water in the food boils and ruptures cells.
p.224 Liquids should be frozen before vacuum packing to prevent them from clogging the vacuum pump. Food should be cool to prevent water boiling at low pressures.
p.230 Better temperature control with proportional integral-derivative controller than with a bang-bang thermostat. Fuzzy logic even better.
p.233 Adding a temperature controller to a rice cooker or crock pot can make it a sous vide water bath. Hot and cold spots may develop; an aquarium water pump or bubbler helps against this by circulating water.
p.234 Underpowered heating elements and crowded baths create cold spots for food.
p.241 Hot water running in a sink or putting a bag in a thermos with hot water can be used for sous vide. The temperature requires experimentation.
p.243 Equilibrium cooking: water in the sous vide bath 1-2 degrees above desired food temperature. Uneven food cannot overcook, but food takes a long time to reach the target temperature.
p.245 Cooking time proportional to food thickness squared. Keep sous vide portions small.
p.247 A tenderizing bath at 50 degrees can be used between scalding and final cooking to activate calpain and cathpepsin that break down contractile proteins of meat. Scalding is necessary to reduce bacteria if a 50-54 degree bath is used.
p.250 Melons can be ripened in a 38 degree sous vide bath. Enzymatic reactions speed up. Some foods can’t be aged this way, e.g. avocados.
p.254 Quick chilling is possible in a sink with ice. Quick chilling preserves flavours (juices thicken, so leak less, aromatics evaporate less), lowers chance of bacterial growth.
p.255 Speed of chilling limited by conduction through the food, not the power of the chiller.
p.257 Domestic refrigerators often reach 11 degrees instead of the promised 2. Opening the door raises temperature further. Use a digital thermometer to find the hot and cold spots in the fridge. Keep hot spots below 5 degrees. Try to store sous vide bags just above freezing temperature.
p.258 Colder freezing is better, because chemical reactions are slower. Quick freezing is better, because it creates small uniform ice crystals. Liquid nitrogen freezes the surface quickly and cracks thicker food.
p.259 Cooking directly from frozen minimizes food degradation, but takes time and energy.
p.260 Salt brine freezing: 400g salt per 1 litre of water. Add 1 kg of ice, wait for 2/3 of it to melt. Water should be at -15 now. Submerge packaged food, stir and add ice to prevent warm spots.
p.261 Melting ice crystals sometimes refreeze as food thaws. Freezing and thawing not symmetrical, because ice conducts heat better than water. Thawing creates an insulating water layer.
p.267 Blanch food before sous vide. Sear before or after or both. This will firm the surface, so it holds shape, and also sanitize. Also destroys some degrading enzymes. Use water as hot as possible. Water preferred to steam because it raises the temperature faster, so needs a shorter time.
p.268 To get the flavour of searing, can brown some bits of food at high heat and pack them with the sous vide cooked food. Presearing should be avoided for lamb and other meat, because it forms chemicals with off-flavours in later sous vide. Can remove skin, dehydrate, crisp it and then serve with sous vide cooked meat.
p.290 Surface area and volume scale differently as food is divided into smaller pieces. To extract flavour (for stocks), grind as fine as possible.
p.291 Pressure cooking accelerates flavour extraction. Turbulence from boiling emulsifies fat and food particles into the stock, making it murky. Don’t let pressure cookers boil, steam should not rise from the safety vent.
p.293 For very clear stock, remove with flexible tube below the fat. Or chill, poke a hole in the solidified fat and pour out.
p.299 Perception is biased by the order of alternatives. A valid taste test must correct for this. [with food, even more: the taste of previous food mixes with the new] Samples should be repeated for each taster.
p.317 Smell more important to food experience than taste.
p.320 Extracting essential oils from plants, steam distillation is the old technique, but heat can destroy some molecules. Rotary evaporators, vacuum condensers, supercritical carbon dioxide and solvent extraction get the essential oil without heat.
Skimming fat from a stock removes some fat-soluble flavour compounds. Some of these can be extracted from fat by mixing it with ethanol and then letting it settle. After adding the flavoured ethanol to food, the excess ethanol can be evaporated off.
p.322 Essences in concentrated and diluted form may smell completely different.
p.323 Enfleurage is pressing aromatic plants into solid fat. After a few days, the plants are removed, the fat is melted and washed with alcohol to extract the scent.
p.324 Essences are often flammable and should be refrigerated to preserve quality. Wear rubber gloves. Only use food-grade essences in food. Predilute in fat or ethanol.
p.326 Flavour can be extracted by vacuum sealing the aromatic plant with alcohol and heating.
p.328 Wash and dry plants before soaking in fat to prevent bacterial growth.
p.332 Juicing requires rupturing cells. Spinning blades, centrifuges, presses are used. The acidity of the juice destroys the aromatic oils over time.
p.335 Pectinase enzymes are used in juicing to break down cell walls. Osmosis due to sugar or salt also draws juice out of food. Ice crystals in frozen plants rupture cells, help with juicing. Thawing, the most concentrated juice comes out first. Ultrasonic baths increase yields.
p.338 Fresh taste is difficult to store, because enzymes break down flavour molecules. Add some fresh juice to old to renew the flavour. To prevent juice from browning, refrigerate. Pulp browns first, because the enzyme concentrations are higher. Remove pulp to preserve colour. Add antioxidants like ascorbic acid, or preservatives (sulfites, sodium benzoate).
p.339 Tropical produce (mangoes, bananas, strawberries, avocadoes, tomatoes) should not be chilled before juicing. [no explanation] Remove air to reduce browning.
p.346 Jus, or meat juice is not the same as a stock. Maillard reactions, more concentrated, different compounds.
p.352 In addition to filtering, agar and freeze clarification can remove fine particles. Centrifuging, vacuum or pressure speeds filtering.
p.358 Fining chemicals modify the substance to be removed to make it easier to remove. Polarized fining agents can bind the target substance. Pureed raw meat, egg whites, methylcellulose, charcoal.
p.361 Centrifuges must be safety tested periodically. A failure releases energy like a bomb. Balance a centrifuge. The air friction can heat the contents. Best centrifuges are cooled.
p.368 Adding liquid with density intermediate between the compounds to be separated allows a cleaner centrifuge separation.
p.370 A frozen gel can be used as a filter. Add gelatin, freeze, then put in a strainer and thaw in the fridge. Gelatin remains solid at fridge temperature.
p.373 Agar gel can be used at room temperature as a filter. Squeeze the gel in a cloth to extrude juice.
p.379 For concentrating flavours, evaporation by heat or vacuum or freezing and removing ice crystals are simple, rotary evaporation, vacuum concentration and reverse osmosis complicated. Evaporation removes also volatile flavour compounds.
p.380 If you can smell the aroma in the kitchen, the food is losing it.
p.384 Distillation equipment may be illegal in some places. Or using it on alcohol may be illegal. Rotary evaporator separates liquids by boiling point. In alcohol distillation, methanol, acetone evaporate fastest, then ethanol, then propanol etc. Distilling vodka is complicated.
p.396 Liquids with different freezing points can be separated by slow freezing and removing ice crystals. Aromatics stay in, but the process is slow and cannot concentrate much.
p.401 The finer the powder or puree wanted, the more power is needed. Kick’s law: energy required is proportional to length of particle before grinding divided by length after grinding. Colloid mill and Pacojet the most advanced grinders. Pulverizing heats food.
p.408 Pacojet designed for ice cream and sorbet.
p.412 Food processor is between dry milling and wet milling, versatile.
p.414 High pressure homogenizers shoot jets of food at a plate, or jets of air at food or pulsate air pressure to compress and decompress food. The machine must be cooled to prevent food from cooking. Ultrasonic homogenizers use water pressure waves (sound) to induce cavitation. The bubbles imploding rip food apart. Works on thin liquid.
p.420 A rotor-stator homogenizer is like a food processor, but the blades pass micrometres from the stationary casing.
p.428 Drying food is slow, because water diffuses slowly through the food. If the surface dries too fast, it forms a hard crust, slowing further drying. Some water in the food is bound to other chemicals, not free to evaporate.
p.429 Dipping in nearly pure alcohol can dry food by osmosis. Salt and sugar similarly dry by osmosis. Microwaving at low power dries food.
p.430 Water activity measures the amount of free water. Pure water has water activity 1. Most bacteria don’t grow with water activity below 0.91, yeast not below 0.87.
p.431 Dry boxes keep dried food from becoming sticky. They have silica gel on the bottom or are kept under vacuum.
p.432 Drying with air, lower temperatures keep more aromatics in food. Slice food thinly.
p.433 Vacuum drying removes aromatics just like heat drying, but doesn’t cook the food. Vacuum dryer can be used to expand a foam, then set it to get very light meringue.
p.434 Drying time proportional to the square of the food thickness.
p.438 Spray-drying uses high surface area, low volume of small droplets to dry liquid into a powder. The liquid must contain 40-60% of solids by volume. Store powders airtightly, keep from light.
p.444 Freeze-drying using vacuum is very slow. Ice crystals sublimate, vapour is captured by freezing it to a cold condenser. Less damage to food, because water does not move through it, but becomes gas throughout. Food must be frozen to below the glass transition temperature, which is -12 to -10C for meat, -50 to -35 for plants. Sublimation cools food, so slight heating is needed.
p.447 Bound water can only be removed by heating the dried food. Freeze-dried food absorbs moisture from the air. Especially hygroscopic, e.g. sugary food, which becomes soggy in minutes.
p.435 Above the glass transition temperature, some of the water in the food becomes liquid, flows, collapses the food’s internal structure. This changes texture and slows the drying process.
p.457 Liquid nitrogen cools food fast, but is inefficient for bulk, because its heat absorption capacity is low. Bubbles form next to warm food, slowing heat transfer.
p.458 Spraying liquid nitrogen on a mollusc’s hinge pops it open.
p.459 Don’t eat dense frozen foods at low temperature, they cause frostbite.
p.460 Frozen food can be shattered for interesting texture. Food can be frozen, then seared in hot oil to get a crispy crust and juicy middle.
p.464 Carbon dioxide in drinks diffuses through the gut wall into blood and is exhaled in minutes. Any watery food can be carbonated. Treat liquid nitrogen like hot oil – safety goggles, gloves, nonporous clothes.
p.469 To carbonate fruit, put it in a cold pressure chamber with carbon dioxide. The gas diffuses in through the peel.
p.470 Truffles keep better if stored in CO2.

Vol. 3
p.6 Muscle fibers are grouped in bundles, which in turn form larger bundles, etc. Meat grain is formed of fascicles, mid-level bundles. Collagen keeps bundles together. Myosin and actin form myofibrils, contract muscle cells.
p.8 Whole muscle surrounded by epimysium (silverskin), fascicles surrounded by perimysium, fibers by endomysium.
p.9 Collagen fibers consist of many strands of two kinds of tropocollagen cross-linked together. The more a muscle is worked, the coarser its grain and the tougher the meat.
p.10 The type of collagen in tough meat is more resistant to heat breaking it into gelatin.
p.11 At high cooking temperatures, collagen shrinks, squeezing juices from the meat and making the meat denser. For tough cuts, low temperature and long cooking time is often best. Slow-twitch muscle fibers are darker, fast-twitch lighter.
p.12 All muscles contain both slow- and fast-twitch fibers, but in different proportions. More fat in dark meat, because the endurance muscle requires long-term energy. Fat makes dark meat more flavourful. Red myoglobin transports oxygen to muscle cells.
p.14 Slow-twitch muscles contain more myoglobin, making them dark red.
p.15 In high-endurance animals, intermediate fibers provide fast movement aerobically. Dark muscle fibers thinner. Temperatures above 60 break myoglobin down, making meat pink, then grey.
p.18 Fat has 37 J/g energy, protein 17 J/g, gasoline 46 J/g.
p.20 Fish have less complex muscle, less collagen, because water supports them and movement in water is simpler. Less difference between muscles. Fish are cold-blooded, their proteins don’t tolerate heat well, so cook at lower temperature than meat. Easy to overcook.
p.21 Fish muscles (myotomes) shaped like W and overlap, separated by collagen myocomma. Tuna swims long distances fast, so has red slow-twitch fibers. Tuna should be treated like land animal meat.
p.22 Pin bones in fish are floating (not attached to skeleton).
p.24 Octopus and squid meat contains a lot of tough collagen. Muscles cross in layers. Skin tough, should be removed. Muscles scored with a knife or tenderized some other way.
p.26 Scallops best cooked by searing the surface, brown nicely. Their fast-twitch muscle is high in glycine (sweet) and glycogen.
p.27 Abalone foot is high in connective tissue, best sliced thinly and eaten raw. Heat makes their collagen very tough. The saltier the water, the more savoury the shellfish.
p.28 Crustaceans just about to molt or just molted are not as tasty. In the 18th century, Massachusetts limited the lobster given to prisoners, as it was considered trash food. 18 kg lobsters were common. Crustacean meat contains protein-degrading enzymes that make it mealy, unless it is very fresh or heated to a high temperature. Cook to a low temperature and serve immediately.
p.30 Crustaceans about to molt feel light, because they are partly empty. They reduce muscle mass before shedding the shell. Just molted are light in colour, greenish, more water, less muscle. Best for eating have deeply coloured shells, are heavy with dense muscle. Maillard reactions occur at low temperature due to sugars and amino acids in crustacean meat.
p.32 Humane slaughter and humane rearing make for best meat. After death meat pH falls from 6.8 to 5.5 as cells burn their energy reserves.
p.34 With energy exhausted, actin and myosin bind together, causing rigor mortis. This makes meat tough. Enzymes break proteins down as meat ages, so rigor mortis passes. Protein fragments contribute to taste. If the animal is scared at slaughter, adrenaline is released, which makes muscles burn energy fast. Warm carcass and low pH cause proteins to break down fast, making meat pale and mealy, exuding moisture.
p.35 Animals cold, hungry or tired at slaughter have little energy in their muscles, so pH stays high, rigor mortis sets in too soon. Meat is dry, firm and dark, tough and spoils easily because not acidic enough. If a carcass is cooled before rigor mortis to below 15 degrees, muscles revive after rigor passes and contract by up to 50%. This makes meat tough and dry.
p.37 Bluefin tuna are stunned on capture, brain destroyed and spinal cord reamed with filament to prevent nerve signals to muscles. Fish then frozen to -60.
p.39 Meat aging means enzymes breaking down muscle.
p.40 Muscle becomes meat after rigor mortis passes. Truite au bleu is trout cooked immediately after removing from water, before rigor mortis. The slime on the skin becomes blue, the flesh is sweet due to the remaining energy reserves, the pH is high.
p.41 Red meat ages slower than white, younger flesh ages faster. Wet or dry aging makes no difference to the enzymes. But dry aging dries the meat, concentrating the sugars and amino acids. It oxidises saturated fats in beef, giving nutty and cheesy taste. Aged meat is juicier. Unsaturated fats in pork or fish go rancid with dry aging.
p.50 Slicing meat across the grain produces 10 times less bite resistance than with the grain. Let thin slices fall on wax paper, which supports the slice and prevents it from falling apart. Raw meat is harder to slice. Cool it to -1.5 to make it stiffer, but not frozen.
p.51 Jaccard tenderizer has 2 mm wide blades, usable on any meat except bones, nigh undetectable. Jaccarded meat retains 5-15% more moisture when cooked. Conjecture that myosin leaking out of muscle cells thickens juices, slows their leakage from the meat. Or collagen shrinks less when cut. Surface contamination can enter the interior with Jaccarding, so blanch or sear surface before puncturing.
p.70 Myosin and other proteins bind into a gel and trap water when heated.
p.72 Meat conducts heat poorly, so a steak over 2cm thick on a pan has a rare top even after 2 hours of frying. Searing does not seal in juices, the meat is porous. Frying meat has a desiccation zone, boiling and conduction zones. These make heat move nonlinearly.
p.75 Water expands 1600 times becoming steam. Steam creates fissures in cooking meat along the grain.
p.76 For protein-cleaving calpains to remain active as meat ages, calcium is needed, which can be injected as CaCl marinade. Rule of thumb that a 10 degree rise in temperature doubles reaction rates, but wide variation exists.
p.78 Enzyme reaction rates greatest just below the temperature they denature. To maximize reaction, cook at 39, then at 49. In some meats, enzyme activity undesirable, makes mushy.
p.79 Collagen breakdown increases exponentially with temperature, depends on cross-linking of collagen fibers and other unknown variables. Collagen shrinkage is much faster than its breakdown.
p.80 For juicier meat, cook long at low temperature to reduce collagen shrinkage.
p.82 To cook both the duck skin and the fat under it, remove skin and fat, cook sous vide at 55 degrees for 24 h and reattach. Otherwise skin remains rubbery. Could also cryosear.
p.83 Fat itself melts between 15 and 40C, but fatty tissue also has collagen etc. Rendering above 85 degrees ruptures fat cells and collagen shrinkage expels the fat. Could also grind or puree tissue to maximize fat yield. Cooking at 60C for 24-72 h tenderizes fat tissue. Tuna, swordfish overcook above 50C.
p.84 Tough cuts contain a lot of collagen that becomes succulent gelatin with long low temperature cooking. Salt makes the protein gel in cooked muscle fibers stronger and more elastic, so brined meat is chewy. Fat contributes to flavour, so is added e.g. by larding (inserting into meat) or barding (wrapping fat around meat). Tough cuts have more fat and the larger fibers have more flavourful protein fragments and nucleotides. Letting meat rest after cooking allows the liquid inside to thicken into gel, leaking less.
p.87 Raw meat is bland, low in protein fragments. Raw seafood is tasty, because saltwater animals concentrate small molecules (primarily trimethylamine oxide) in their flesh to maintain water against osmosis. Maillard reactions occur at lower temperatures as a result. The saltier the water, the tastier the meat in it.
p.88 Salt and especially acid increase salivation, enhancing flavour.
p.89 The best cooking temperature is commonly 18 degrees above the living animal’s temperature (water temperature for fish).
p.90 Onions, leeks, garlic (Allium spp.) provide sulfur compounds for the Maillard reactions, enhancing meat flavour.
p.91 To enhance the Maillard reactions, raising the pH by alkaline marinade or adding sugars helps. Above 180 pyrolysis (charring) replaces the Maillard reactions. Warmed-over flavour from oxidation of unsaturated fats in cell walls that break down when cooked meat is cooled. Nitrite in curing salts slows this, lack of oxygen too.
p.92 Myoglobin reacts with oxygen to become bright red, so red meat left in air is colourful. Without oxygen, myoglobin is deep purplish-red. Partially oxygenated myoglobin is grey or brown, so sealed but not vacuum-packed meat looks unattractive.
p.93 Carotenoid pigments in bird diet accumulate in fat, including egg yolk, changing its colour. Myoglobin breaks down above 60 degrees, below that it loses oxygen when heated, but can become red again if cooled and aerated.
p.94 Pork and poultry overcooked to above 80 are sometimes pink, because the cytochrome pigment has lost oxygen with heat. Airing the meat turns it grey.
p.95 CO or NO2 gas can make meat remain red despite cooking by binding myoglobin. Both CO and NO2 are poisonous.
p.118 Skin has a fat layer under it, thicker for waterfowl (insulation). Fat is a tough cut because of the collagen.
p.119 Peking duck is from force-fed ducks, body cavity filled with water, air blown under the skin, skin blanched, glazed with sugar and maltose. The bird is then let dry, roasted in a brick oven over fruitwood. The crisp skin is considered the main delicacy.
p.122 Cockscombs and wattles are fancy French food. Wash inside and out, parboil and rub. Then stuff, braise or cook sous vide. To reduce the fat content of fatty meat such as duck, use a stiff wire brush to poke many holes in the skin. This allows fat to leak when heated. Puffed skin is a foam created by steam when partially dried skin is heated.
p.123 Thick skin, such as pork, should be partly dried before heating, otherwise the outer layer will burn before the rest cooks. To dry, leave uncovered in fridge, maybe add a fan. Loosen the skin from the meat to slow moisture transfer. To puff skin, it must be heated to 180-200 quickly so it softens before the water evaporates. The amount of water in the skin must not be too high or low, similarly to puffed starchy plant food.
p.125 Sous vide keeps too much moisture for later puffing, use a combi or water vapour oven.
p.126 Pork skin can be removed, pressure-cooked, dried, ground and crumbs reattached to the meat before deep-frying. Crumbs puff.
p.129 Fish skin secretes mucus containing large polysaccharides, which can be dehydrated by searing in a pan into a crisp glass. Puffed pork rind: dip for less than 1 min in a vat of boiling water with 1.5% glucose, 1.5% sucrose, 9% salt. Cool, cut into pieces, heat to 110-120 to render the fat and soften the skin. Store frozen if needed. Dip in vinegar, then 200 degree oil.
p.130 Small fish with tender scales can be cooked and scales crisped simultaneously. Loosen scales by brushing, hang fish by tail, ladle 200 degree oil against the scale direction for about 2 min until scales stand up.
p.136 Organ meats freshest when frozen after slaughter. High enzyme content degrades them quickly.
p.138 Bile gives liver a slightly bitter taste. Liver is energy-intensive, high in myoglobin. Cooking liver too hot creates sulfur compounds with a strong flavour.
p.139 Migratory birds store fat and glycogen in liver, some over 40% by weight – foie gras. Many small fat vesicles better than few large, because large ones rupture with cooking, making the foie gras greasy.
p.140 Glands like thymus and pancreas should be fresh or flash-frozen, cooked quickly. Should be pale pink to light grey. Cut away surrounding fat, soak in acidic solution.
p.141 Tongue is a crisscross of muscles and connective tissue covered with a skinlike membrane. Tough cut: cook long on low heat, slice thinly. Duck tongue has a bone.
Kidneys must be very fresh. Remove surrounding fat and membrane, remove inner tough core.
Gizzards have layers of smooth muscle with elastin and keratin, which do not break down with cooking, so gizzards always chewy. Cut gizzard open, remove the inner bag and membrane.
p.142 Heart has tough sheaths containing elastin. Remove membranes and blood vessels on the surface. For large hearts, remove lower pumping chambers. Slice and briefly grill to rare.
Tripe is the stomach, chitlins the intestines. In ruminants, each stomach has a different function and thus texture.
p.143 Digestive organs not sterile – scrape and rinse thoroughly, then marinate with acid or the alkaline 2% sodium tripolyphosphate, rinse and grill, pressure-cook or sous vide.
Bones don’t have much flavour, but the attached connective tissue and muscle do.
p.144 White marrow in large bones is fatty and flavourful, red marrow in small bones not much. Cook marrow bones at 60C for 40 min. Blood’s clotting ability is sometimes good. If don’t want clotting, keep temperature under 70C.
p.145 To render fat, fat cells must rupture. Grind fatty tissue (e.g. skin), heat 2-4 hours. Pressure cooker best for wet rendering – avoids boiling which emulsifies fat with water. Dry rendering in a pan gives more flavour, but the fat goes rancid sooner and has a lower smoke point.
p.152 Salting meat preserves it only if it is also dried. Flesh with salt content <2% is brined, about 3% cured, drying then brings salt content above 5% and preserves.
p.153 Salt diffuses in meat 100 – 1000 times slower than heat. Speed inverse square of thickness. Brining causes flesh to soak up water, contrary to osmosis. Chloride ions bind to meat proteins, the negative charges push the fibers apart, tenderizing the meat. Water fills the gaps. Flesh swells until 6% salinity if surrounded by water, then starts to shrink. Protein fragments form a gel. Goal of brining is to bind juices, but not oversalt.
p.156 Salt diffuses slower through skin, fat and bone than meat.
p.157 CaCl swells meat more than NaCl because of 2 chloride ions. Ca stimulates aging enzymes. Use <0.03% to avoid metallic bitter taste. Sodium tripolyphosphate and sodium hexametaphosphate dissolve myosin, greatly accelerate brining. For brining, use <0.05%. Difficult to dissolve, don’t use hot water.
p.158 Use as much water as meat by weight, make water salinity double the desired meat salinity (2% of total meat and water weight). Equilibrate: check with salinity meter that the water salinity has halved. Jaccard tenderizing, injecting or vacuum tumbling the meat accelerates the brining.
p.160 Most curing is with NaNO2, highly reactive, antibacterial, preserves myoglobin, prevents rancidity. To slowly replenish NaNO2, NaNO3 is added. At browning temperature, NaNO2 becomes carcinogenic nitrosamine. Paprika, garlic, beet, celery, lettuce contain NaNO2.
p.165 Blanch meat before curing to kill bacteria – some can survive on cured meat and cause stink and discoloration.
p.166 To speed brining, vacuum tumble, inject brine, pump it into blood vessels, Jaccard tenderize beforehand.
p.167 Ripening after curing allows proteins to break into flavourful fragments. Fats oxidize.
p.173 Drying requires surface evaporation at the same rate as water diffusion from the interior. Freshly cured meat or fish usually dried at 15-20C at humidity 90% initially, 70% at the end.
p.174 When injecting brine, push needle nearly through the meat, then push plunger while slowly withdrawing the needle. Inject at least every 2.5cm.
p.190 Marinading uses salt like brining, but also changes pH or uses alcohol or enzymes to break up proteins.
p.192 Muscle pH 6.8, meat 5.5. Muscle fibers repel each other with negative charges, but in meat the charge is absent, so meat stores less liquid.
p.193 Acidic marinade makes meat fibers repel each other with positive charges. Below pH 4.8, muscle starts to get a cooked texture. Acid and alkali tenderize collagen.
p.194 pH is on a log10 scale: 1 unit of pH change is a tenfold H+ ion concentration change.
p.195 Pineapples, papayas, figs, kiwis, some other fruit and ginger contain proteolytic enzymes. Bromelain from pineapple breaks down collagen, not just meat protein. Pasteurization destroys the enzymes. Fresh fruit juice cannot be used in gelatin-based jelly, because gelatin uses meat protein for gelling. Use agar, other nonprotein gel compounds. Alcohol at high concentration tenderizes meat, but dries it.
p.198 Fermentation is like acidic marinading, because the Lactobacillus species used produce lactic acid. This keeps other microbes at bay.
p.200 Lutefisk: NaOH is used to turn fish into jelly.
p.207 Pressure speeds marinating, at 5.5 bar with marinade 10% of the weight of the meat, 2cm cubes of meat absorb 6.5% by weight in 20 min. Shake to coat meat evenly.
p.214 A smoke gun draws air through smoldering sawdust and exudes smoke. Like smoking a pipe. Can impart smoke flavour to food.
p.216 Barbeque tries to both flavour the meat with smoke and tenderize it with long low heat. Foil wrapping tries to prevent drying out. Better to smoke for flavour and then sous vide for tenderness. Cooking denatures proteins, fewer remain to react with smoke. Smoking after cooking takes longer.
p.220 Sausage, meatballs, patties rely on meat gelling to bind together, but too much gelling makes the food rubbery. Meat grinder should be cooled with ice water or liquid nitrogen to cut meat more cleanly.
p.222 Myosin leaking from meat forms the gel of sausage. Shrimp, crawfish and lobster bind strongly, can get rubbery. Pork leg and shoulder good binders, as is blood.
p.223 Organ meats weak binders. Fat resists binding. Above 6% salt draws myosin out, binds stronger. Phosphate salts strongly extract myosin, use <0.3%. Casein, whey, egg white, alginate are added binders. 5-10% water added to help coat meat with binding agent, make sausage juicier. Sausage is 25-30% fat.
p.224 Fat should stay emulsified to prevent greasy texture. Adding unruptured fat tissue directly is one way, requires coarse grinding. Connective tissue should be removed. Keep grinder cold to prevent rendering fat.
p.225 Second way is to puree meat, fat and water finely while cold, creating a colloidal suspension. Protein must gel before fat melts to prevent fat droplets from merging. Sausage heated in stages for this, to 55C and then 65-71C. Third way is emulsion – fat suspended in water and nonmeat protein.
p.228 Different meats and fat ground separately for sausage.
p.229 Grind meat medium first, then fine.
p.233 Cook sausage the same way as the meat it is made of.
p.240 Sausage mix should be stuffed or formed quickly, otherwise it firms. Soak casing for 30 min to make it pliable, remove salt. Leave no air pockets, prick and squeeze them empty to prevent spoilage.
p.241 Plastic sausage casing should not be PVC, because fat absorbs some compounds of PVC.
p.246 For fermented sausages, the bacteria do not feed on meat, but the added carbohydrate dextrose (0.5-1% of meat weight). Starving fermentation bacteria lets spoilage bacteria take over.
p.250 Fermented sausage mix has >2-3% salt to preserve. Semidry sausage loses 25% of weight, dry 50%. Transglutaminase (Activa) crosslinks meat proteins, gelling them.
p.252 Humidity and temperature above 58 degrade Activa, keep in freezer after opening or vacuum pack. Bonding takes 6-12 hours in the fridge, 5 min at 55C, meat surfaces must be pressed together lightly.
p.262 Of plant parts, only fruits evolved to be eaten (for seed dispersion), others have defenses against eating. Seeds in a fruit often toxic for intact excretion.
p.265 Avocado seeds large, previously dispersed by mammoths, giant sloths, now by jaguars who are attracted to the fat content.
p.266 Only a tiny part of a plant’s mass comes from soil, most is water or absorbed CO2. Soil is like vitamins, needed in small amounts.
p.267 Plant cell wall is of cellulose. Cells linked by pectin and hemicellulose, which degrade with heat. Even cooked cell wall never fully digestible – it is fiber. Only 3% of betacarotene from raw carrots digested, 6% from cooked, 21% from pureed raw, 39% from pureed oil-cooked.
p.269 Raw plant food is low in accessible nutrients. Animals either eat large quantities, have thorough multichambered bacteria-assisted digestion or eat only energy-dense seeds, fruits and tubers. Raw-foodies need blenders and juicers to get enough nutrients.
p.270 The same perception of chili hotness needs 30 times more capsaicin in neutral oil than in water. Various factors affect chili taste.
p.273 Raw spinach has oxalic acid that binds iron – only cooked spinach is a source of iron. Cell walls start breaking at 88-92C.
p.274 Red cabbage juice is a good pH indicator, because the anthocyanins are red with acid, blue or purple at neutral pH, green and then yellow with alkali.
p.276 Add 1% sugar to potato-boiling water to prevent natural sugars from leaching out. Steaming can take longer than boiling, because the condensation water insulates. Baking soda makes cooked beans mushy, vinegar hard, because pectin and hemicellulose dissolve faster in alkaline water.
p.277 Vegetables sweeter when cooked in oil than water, because sugars not soluble in oil.
p.278 Salt slows cell wall breakdown. Carbonate ions in hard water make chlorophyll in green vegetables olive in colour. Use deionized water and pure NaCl, not sea salt, to preserve fresh green colour.
p.280 Staleness of bread comes from crystallization of starch granules, not drying. Melting the starch at 90C improves stale bread, but not to freshness. Floury potatoes better for mashing than waxy, because the large amount of starch swells with water, pushes cells apart. Cooled mashed potatoes gel. Add fat to prevent this. To prevent mushiness in starchy plants, heat to 60-65 for an hour, cool, then cook – the heating stimulates pectin methylesterase, which firms cells.
p.282 Apples brown when damaged, because polyphenol oxidases oxidize, creating brown antimicrobial pigments.
p.283 Heating destroys browning enzymes, antioxidants like vitamin C slow them. Industrially blanched and frozen peas greener and sweeter than farm fresh, because some enzymes destroyed. Tropical fruit enzymes more heat-resistant. Climacteric fruits (apple, banana, pumpkin, tomato, eggplant, avocado) ripen after picking, accelerated by heat and ethylene gas.
p.284 Synchronized ripening can be used for predator satiation or to attract seed dispersers en masse. Ethylene coordinates this in fruits.
p.286 For plant foods, a wide range of temperatures gives the same result. Cook sous vide to about 90C to prevent dilution of liquids and overcooking.
p.300 Pressure cooking creates novel flavours, caramelizes onions (add baking soda to catalyze). Overcooking a risk for delicate foods.
p.310 Microwave cooks unevenly, fine for plant foods, dehydrating. To “deep fry” herbs, coat in oil and microwave. Sous vide bag keeps steam close to food, evening out the heat, reducing oxidation.
p.311 Microwave at lower power longer to even out hot spots.
p.316 Frying in batter fries only the batter, the food inside is steamed. To insulate food, batters are often foams or contain foams, e.g. breadcrumbs.
p.320 Frying without batter works well if the food is starchy or browns on its own with heat. Fry more sugary foods at lower temperature to avoid burning the sugar.
p.322 Standard french fry recipe: fry in 150C oil, cool, then fry in 190C oil. Triple cooked chips: boil potatoes until falling apart, vacuum dry, fry at 130C, vacuum dry, fry at 200C. Pectin-dissolving enzyme creates better texture. Mealy potato sorts preferred.
p.327 Vegetable sheeters and slicers can create vegetable noodles with interesting texture. Fry or boil.
p.328 Chips can be made from many porous fruits and vegetables by filling vacuoles with starch, drying and frying. Reduce oil uptake by 20% by adding 0.5% of methylcellulose to starch slurry.
p.332 Batter clings better to drier foods if they are dipped in milk or egg.
p.338 For breaded frying, 3 coatings: adhesive powder, liquid and breading.
p.346 To ferment, inhibit spoilage bacteria early on with salt, hold at 18-24C to promote acid-producing bacteria.
p.358 Heat shocking: briefly exposing fresh fruit or vegetables to 37-45C helps retain crispness and freshness. Can dramatically extend shelf life, halt ripening.
p.362 Vegetables and pasta can be smoked for flavour. The 90C smoke needed for cooking vegetables dries out the food unless humidity controlled.
p.365 Dried sugary foods become leathery, absorb moisture from the air. For crisp dried food, add pectin, a hydrocolloid, starch or maltodextrin. Colour dulling in dried food is partly the optical effect of a spongy texture.
p.374 Frozen milled nuts more likely to become powder than paste.
p.376 Bread is effectively a foamed gel. Bread or pasta flour needs enough protein as a binder, e.g. in wheat flour gliadin and glutenin form gluten.
p.378 Pasta requires the right ratio of protein and starch, is formed from a stiff dough. Egg is sometimes added as binder.
p.390 Vacuum sealing porous fruits and vegetables and then exposing to atmospheric pressure bursts vacuoles and then compresses, makes juicier, allows infusing with another liquid.
p.392 Pectin gel glues fruit together, but weakly.
p.393 Apples can be infused to double weight, because a large fraction of them is air.

Vol4
p.6 Dynamic viscosity(=absolute viscosity) measured in centipoise (1 cP =1000 Pa*s). Below -270C, liquid He becomes a superfluid with 0 viscosity. Most liquids less viscous at higher temperature. Water 1.8cP at 0C, 1cP at 20C, 0.5cP at 60C and 0.3cP at 100C. Liquid nitrogen 0.2cP. Ketchup is shear-thinning, meaning flows (nonlinearly) more easily the more force is applied. Ketchup acts like a solid when bottle held upside down, but squirts out in large quantity when bottle shaken.
p.7 Methods for thickening liquid: raise concentration of solids, particles, starch, sugar, protein, fat, whip into foam. Proteins may coagulate, forming a gel.
p.10 Human mouth can detect solid particles down to 7-10 micrometres. These feel gritty.
p.11 Thickeners release flavours at different speeds. Starch releases slowly, dulls taste, because makes up a large fraction of the thickened liquid. Hydrocolloid gums are a small fraction of thickened liquid, release flavour faster. Fat releases flavour slowly.
p.12 Liquid with suspended solid particles is called a colloid. The most effective thickeners are long molecules that bond each other (starch, gums), causing high steric hindrance.
p.13 Oil can be thickened with tapioca starch that adsorbs oil. Mixing oils with different melting points can thicken the low-melting-point one.
p.15 Many thickeners work only at a certain temperature, destroyed by a freeze-thaw cycle. Some restored by reheating. Natural starches gummy and unusable after reheating. The large molecules of thickeners can make the food opaque.
p.16 Fizzy drinks contain gum arabic as an emulsifier to keep flavour oils in suspension. Thickening agents can have synergy, e.g. xanthan gum and locust bean gum form a gel together, but neither alone does. pH affects some thickeners.
p.17 Syneresis means weeping – thin liquid separating from a thickened liquid.
p.20 Natural starches consist of amylose (a linear polymer) and amylopectin (branched). Plants arrange starches in granules – large for potato, small for corn or rice. Granule size affects mouthfeel.
p.21 Natural starches must be dispersed in water and hydrated. The difficulty is that wet granules stick to each other, forming lumps. Heating causes gelatinization – the breaking of the crystal structure of starch, making it amorphous. This is the first step of thickening or gelling.
p.38 Dispersing hydrocolloids (flour, gelatin) is easier in cold water where they dissolve slowly – this gives time to break up lumps. Then increase temperature to fully hydrate, stir with hand mixer.
p.40 Some hydrocolloids require heat to hydrate, which may depend on ion content. Can disperse hydrocolloid in oil first, then emulsify with water. Can mix hydrocolloid dry in some powder in a blender.
p.67 Bread, scrambled eggs, cheese and tofu are all gels. Thickening carried further. Syneresis is weeping of liquid from the gel. Carrageenan, xanthan gum, and locust bean gum are freeze-stable, no syneresis after thawing. Gelatin from collagen creates a 3D mesh when it cools, trapping water molecules. Gelatin melts near the body temperature of the animal from whose collagen it was made.
p.68 Ballistic gelatin: 10% 250-Bloom gelatin in water, cool to 4C – mimicks the body’s response to bullets. Bloom is a unit of gel’s rigidity.
Apples and citrus peel contain pectin, a natural gelling agent, requires acid and sugar to gel.
p.70 Gelatin is a thermo-reversible gel: melts and gels repeatedly when heated and cooled. Egg white is thermo-irreversible. Coagulant is a substance helping to form a gel, e.g. ions of Mg, K, Na, H (acid gives H-ions). The enzyme rennet (chymosin) is a coagulant. Transglutaminase links the amino acids of proteins.
p.72 Sequestrant is a substance inhibiting coagulants.
p.74 Egg starts gelling at 55C, whites gel at a lower temperature than yolks.
p.82 “Century eggs” are made by vacuum sealing them with a brine of water and sodium hydroxide for three weeks. The pH change gives electrical charge to proteins, binding them.
p.84 Heat eggs with milk or cream, and you’ll get custard. Egg to liquid ratio and temperature determine whether the custard is firm and dense, like a frittata, or pourable, like a crème anglaise.
p.100 To give eggs smoke (or herb) flavour, soak them 48h in water with 3.5% of liquid smoke in it.
p.102 Cheeses are dairy gels. Many brands of heavy cream contain carrageenan or other gums to prevent separating – this affects gel recipes. Ricotta and cottage cheese use acid for coagulant, other cheeses rennet. Tofu is made from soy milk by coagulating with a Ca or Mg salt. Other nut milks can also be coagulated to tofu-like gels.
p.104 Press dairy and soy curds while still warm (65-75C) to bond them.
p.124 Many new hydrocolloids are polysaccharides. Cellulose does not gel. Gels requiring positive ions (Ca is best) are alginate, gellan, iota carrageenan. If ion concentration too high, then the gelling agent will not hydrate or requires high temperature.
p.125 Sequestrant, e.g. sodium hexametaphosphate or sodium citrate, binds ions, reducing their effect on gelling agent, which then hydrates at lower temperature.
p.126 Methylcellulose is thermo-reversible, strange: sets with heat, melts with cold. Thus prevents boilover.
p.150 To prevent a gel from slipping off the food it is supposed to coat, prick holes in the surface of the food or dip food in liquid nitrogen first.
p.166 Bananas brown when peeled because of polyphenol oxidase enzyme. To deactivate enzyme, cook bananas in peel at 88C for 12 min.
p.178 Most gelling agents can be used to form fluid gels (solid until shear applied, then fluid). Best are agar, gellan and lightly cooked egg. To make a fluid gel, either make a solid gel and blender it, or stir gel while it is setting.
p.184 Spherification (ionotropic gelation) is used to encapsulate pharmaceuticals, creates solid sphere with liquid center. Hydrocolloid such as alginate is dropleted into a calcium ion coagulant bath, or calcium-rich droplets into hydrocolloid bath. Adding enough sugar in the setting bath to match the density of the liquid solidified prevents droplets from sinking to the bottom and becoming lopsided. Frozen beads can be dropped into warm coagulant, so outer layer melts and gels, then removed. Heating beads to 85C for 10 min halts gelling progress. Rinse beads twice to remove flavour of coagulant.
p.199 Emulsions are suspensions of fine hydrophobic liquid droplets in water. They are metastable, meaning that over time they separate into component liquids. The droplets are the dispersed phase and the liquid suspending them the continuous phase. Butter is a water in oil emulsion, milk and mayonnaise are oil in water emulsions.
p.200 Mixture of emulsifiers generally works better than its components. A thickener may stabilize an emulsion at a certain concentration, but destabilize at higher and lower concentration. Egg yolk lecithin is an emulsifier for mayonnaise. Rule of thumb that an emulsifier for oil in water should be 5% of the volume of the oil.
p.202 Surfactants are important emulsifiers. These are long molecules, one end hydrophilic, the other hydrophobic. Caseins are emulsifiers that act like surfactants.
Cow milk is yellower than goat’s, because goats metabolize carotenoids better, so less of these reach the milk.
Bancroft’s rule (of thumb): if the emulsifier is more soluble in water than in oil, then the emulsion is oil in water, otherwise water in oil. Depends on temperature, salinity, etc.
p.203 Emulsions are opaque because light Mie scatters (all wavelengths equally). A different scattering is Rayleigh (Tyndall effect), e.g. lowfat milk in water is bluish.
p.204 Ratio of masses of hydrophilic and hydrophobic parts of the molecule is HLB, hydrophilic-lipophilic balance, a rough measure of surfactant properties. A weighting agent, e.g. brominated vegetable oil, increases the density of oil, which helps mix it with water. Emulsifying increases viscosity above that of both mixed substances. Most emulsions are shear-thinning fluids.
p.205 Thickening an oil-in-water emulsion requires a lot of oil, creating a high-calorie oily sauce. Everyday macroemulsions are opaque, have large droplets. Nanoemulsions with droplets 20-100 nm are transparent.
p.211 Many liqueurs are oil-in-water (O/W) emulsions with flavour oils, e.g. transanethole for anise.
p.212 Most food emulsions separate above 70C.
p.213 Clarified butter (ghee) is pure fat separated from butter, which is a W/O emulsion. For brown and black butter, continue cooking after butter has melted and separated, then filter. Add 30% nonfat milk powder before cooking for more flavour.
p.243 Food foam is usually gas in water emulsion. Whipped butter is gas in oil.
p.244 Foam stabilizers: fats, proteins, gelling agents, starches, surfactants, solids. Some overlap with emulsifiers. Antifoaming agents not much used in food. Whipped cream is finer and lasts longer after hot-cold treatment: heat to 30C for 30 min, then cool to 5C and whip. Souffle or caffe latte has set foam: heat causes proteins to set into thermo-irreversible gels. Foaming agents counter each other, e.g. fat breaks a protein foam.
p.247 Souffle relies on the gas pressure in the bubbles to avoid collapse, because the bubble walls are weak egg gel. Cooling or cutting souffle collapses it.
p.249 Foams last less than emulsions, because density of gas and water differs more than oil and water, foam bubbles press into polygons and gas diffuses from small to large bubbles, because surface tension raises the pressure in small bubbles.
p.252 Whisking makes foam by trailing air bubbles behind the wires and breaking existing bubbles into smaller ones. A blender with blades below the liquid does not insert air, so does not make foam. A hand blender held near the surface can insert bubbles.
Gases, unlike solids, dissolve better in cold liquid, so make foam cold.
p.253 Industrial breadmaking inserts air bubbles in the dough, then bakes in a vacuum oven that expands the bubbles and solidifies the foam.
p.256 Whipping siphons use nitrous oxide, which dissolves well in water and even better in fat, does not oxidise food, and prevents bacterial growth.
p.302 Puffed snacks are set foams. Dehydrate food until 11-15% water by weight. Beans should be hydrated, pressure cooked and dried before puffing by deep-frying or microwaving.
p.307 Grains can be puffed directly: coat with oil and microwave barley, rice or amaranth at 800W for 90 s in a sealed paper bag. [Proovisin ise pop-amaranti mikrolaineahjus teha (800W, algul 90 s, siis veel 60s ja 30s), aga läks ainult kõrbema. Ükski tera ei paistnud popkornilaadne valge. Pliidil kuivas potis kuumutades pooled terad läksid popkornilaadseks, pooled kõrbema.]
p.320 Colour of wine mainly depends on how long the wine is in contact with the grape skins, not on the colour of the grapes. Tannins also come from grape skins.
p.327 Grafting is cloning plants, ensures consistency. Most fruits are produced from grafts put onto cloned rootstock.
p.330 Water can be reduced in grape juice before fermenting, sugar added, nanofiltration can take out some large molecules, microoxygenation soften tannins. Alcohol can be removed after fermenting.
p.332 Controlled origin laws require wines to satisfy different rules in different places. Only guarantee region of origin, grape and technique used, not the quality of the wine.
p.334 Blind taste tests show it is difficult to distinguish even red from white wine. Saliva precipitates tannins, so let some into the glass if the wine is too bitter and dry.
p.335 The colour of the room or lighting affects people’s perception of the taste of wine: green and white make it worse.
p.340 Experts’ praise of the taste of wine correlates with its price if it is unlabelled, but correlates with label price if labelled. Non-experts cannot tell cheap from expensive wine based on taste.
p.341 Taste receptors sense many different chemical compounds; their signals combine into taste in the brain. Taste receptors found on tongue, roof of mouth, epiglottis, intestine.
p.342 Decanting separates sediment from wine, oxygenates and outgasses it. Removing bad gases improves taste more than adding oxygen. Reds benefit more than whites. Vacuum filter wine to remove sediment, then run a wine through a blender on the highest setting.
p.347 To store opened wine, replace the oxygen with a different gas, e.g. nitrogen, argon, CO2 (especially for sparkling wine) and put a tight cork on.
p.349 To remove 2,4,6-trichloroanisole that causes corked smell in wine, shake it in a polyethylene bag or filter through polyethylene beads.
p.358 Coffee cherries processed dry, wet or pulped natural. The dry process dries the coffee cherries for up to 4 weeks in the sun, then removes the skin and pulp. The wet process removes skin and pulp, ferments and then dries. Pulped natural omits the fermenting.
p.360 Maillard reactions during roasting give coffee its flavour. At 150-180C, beans crack (like quiet popcorn), darken and swell to double the size. Hotter temperatures lead to a second crack. Beans are at their best 48-72h after roasting, because they lose volatiles over time.
p.362 Avoid oxidation of coffee beans after roasting: vacuum seal with nitrogen. Grind right before brewing, don’t store ground coffee.
p.363 Caffeine was formerly extracted with chemical solvents, nowadays with supercritical CO2 over several hours.
p.364 Brewing extracts about 20% of soluble compounds from coffee. Too low temperature underextracts, making sour coffee. Too high temperature overextracts, causing bitter taste.
p.366 The amount of coffee per unit of water (strength of brew) is different from the extraction percentage (sour vs bitter taste). To move from sour to bitter, grind the beans finer or brew for longer in hotter water.
p.368 Metal filters let oil droplets and particles through, creating a full-bodied flavour. Paper filters result in cleaner, leaner flavour. Cloth averages metal and paper. 55g coffee grounds per liter of water is a good starting point. Brewing temperature 93C. In a coffee maker, rinse the paper filter with hot water before starting. Stop the drip when the coffee grounds are wet through, let them stand for 30-45s and then continue the drip.
p.370 Cold water extracts less acidic and bitter compounds. Let 225g of grounds per liter of water filter for 12h in the fridge, then dilute 1 part concentrate with 3 parts hot water. Cold extracted coffee keeps for 2 weeks.
p.374 Espresso pressure typically 9 bar, temperature typically 95C, adjusted to the blend, roast and grind fineness. Decaf requires different temperature and pressure from ordinary coffee.
p.376 Espresso is the most difficult coffee to make, because the water is in contact with the beans for the shortest time, so small variations in grind size, water amount, etc create big differences. Fine grind is used for espresso, because the water contact time is short.
p.377 Ground coffee has oil droplets that go stale quickly.
p.379 Single shot of coffee uses 7g of grounds, double 14g, etc. Ristretto uses 1:1 water:grounds ratio, espresso 2:1, lungo 3:1, caffe crema 7:1.
p.383 Espresso grounds should be evenly distributed in the portafilter and then tamped down in an even layer. The high-pressure water will find the path of least resistance, so uneven distribution yields a bad shot.
p.386 The stream of liquid that forms an espresso shot changes colour from black to yellow and taste from sour to bitter as more water flows through the grounds, because different compounds dissolve at different rates.

Vol 5, 6 collect the recipes from the other volumes and add more.

Sugar-free, fat-free and low-salt claims

The three main ingredients of unhealthy food are sugar, salt and fat. The packaging of junk food often has claims of sugar-free, fat-free or low-salt in big colourful letters on the front. The trick is that the absence of one of the three ingredients is compensated by a larger amount of the other two, as can be checked from the nutrition information label.
Sometimes the claims on the front of the pack directly contradict the nutrition label, so are downright lies. I have seen packaging with the claim “sugar-free” on the front, with sugars listed in significant quantity on the nutrition label. There are some legal sanctions for falsifying the nutrition information label, but almost no restrictions on what can be claimed elsewhere on the pack, so any contradictions should almost always be resolved in favour of the nutrition label.
I have seen a sugar-free claim on a pack on which the ingredient list included brown sugar. This suggests the existence of a legal loophole (brown sugar not equalling sugar somehow) that the manufacturer wanted to use.
If the manufacturer does not want to outright lie, then a trick I have seen is to claim “no added sugar” or “no sugar or artificial sweeteners” on the pack, but add other sweeteners, e.g. sugarcane juice, molasses, high fructose corn syrup. Similarly, “no added salt” can be bypassed by adding salty ingredients, for example dried salted meat or bacon to a snack mix.
Another trick is to create the sugar in the food during the manufacturing process. For example, heating starch for a long time or adding the enzyme amylase breaks the starch into smaller-molecule sugars. So a manufacturer can claim “no added sweeteners” and yet produce sugars in the food by processing the starch in it.
A similar trick for salt is to add sodium and chloride in other ingredients and let them combine into NaCl in the food.

Seminar food guidelines

The food should be easy to eat from a plastic plate in one’s lap without paying attention to it. It should not require a knife, fork, spoon or chopsticks. Sandwiches fulfill these criteria. Sushi can also be eaten with one’s fingers. Sandwiches should not be so thick that they have to be disassembled to fit in the mouth. Sandwiches should not contain ingredients that are difficult to bite through, for example prosciutto, non-crispy bacon, meat with tendons in it.
The food should not drip or stain the hands, especially with a greasy or otherwise difficult-to-remove sauce. Wraps should neither have the bottom cut off nor contain a thin sauce that leaks through the bottom. Sandwiches should not have contents falling out – avoid a thick stack of many fillings between the breads. A single filling can be thicker, e.g. a chicken breast. Biting into the food should not cause the food to fall apart (rice paper rolls have this problem) or something to squirt out the other end (as happens with sandwiches with a lot of sauce or mayonnaise).
Sandwiches should not require toothpicks to hold them together, because these are annoying to remove. Sandwiches should not be cut into pieces so small that they require toothpicks or that the filling falls out of all sides. The bread should not fall apart when picking up the sandwich.
Avoid ingredients with a strong, specific taste that some people love and some hate. Sauerkraut, pickles, olives, capers, kimchi, herring, anchovies, hot spices and fungal cheese are bad ideas. The food should be like a politician – trying to please everyone, avoiding controversy. Spices and sauces can accompany the food separately, like wasabi and soy sauce with sushi – then everyone can add the amount they like.
Crunchy food (nachos, potato crisps, toast) should be avoided, because the sound of chewing them distracts the audience and the shards may cut the inside of the mouth.
Nuts and small berries (raspberries, blueberries) are difficult to eat when one’s attention is elsewhere, because these tend to roll off handheld plates. Transferring very small food items like nuts and berries to one’s plate at the start of the seminar is also annoying, because these have to be picked up one by one or only a few at a time. To help people fill their plates easily, put nuts, berries and crisps in separate bowls or at least separate piles, don’t scatter them over and among other food. Nuts and small berries in particular are difficult to chase between other foods.
In general, keep different foods separate. For example, sandwich bread touching cut-up fruit tends to soak juice from it and get unpleasantly soggy and sweet. Cheese and dessert touching on the same platter leads to a cheesy-tasting dessert. Separating foods also helps allergic people avoid the triggering ones.
Remove the leaves from strawberries.
If bananas are slightly green, then they are difficult to peel, so a small cut should be made near the stalk from which the peeling can start.
Don’t cut grapes – it makes them go bad in hours. Whole, undamaged grapes keep for days at room temperature.
Fruit should be either in bite-sized pieces (melon, papaya) if there are forks to eat with, or whole so it can be handheld without leaking or staining (apples, bananas). A bad idea is to have long slices of melon that stain hands with juice and don’t fit in the mouth in one piece. If there are no forks, then cut-up kiwis, pineapple and other wet, slippery fruits are a bad idea, because these are difficult to hold and stain the hands.
One strange thing I have seen (and that should be avoided) is salad scattered among sandwiches, without any forks or other utensils to serve or eat it with. The only way was to eat the salad with one’s hands.
Portions that are too large for the average eater (footlong subs, whole chicken breasts) lead to food waste, because people eat only a fraction of the portion and throw the rest away.
The mechanics of eating the food is as important as the taste. The ease of eating of various forms of food can be field-tested in a seminar-like situation: eating sitting, with a small plastic plate in one’s lap, no table, only occasionally glancing at the food.
Similar points apply to stand-up reception food.