Water and steam: boil, simmer, poach, steam, braise

Put a chicken breast in a frying pan and the bottom is at the temperature of the metal, which is far hotter than water can get, and that is what lets it brown. Put the same breast in a pot of water at a bare simmer and nothing touching it is hotter than about 85°C. That is the difference this lesson is about. A pan gives you browning and asks you to watch it. Water gives you something else: a temperature that holds still on its own, so a cook can leave a pot for hours and know what it's doing.

That makes water the right tool for four quite different jobs. It cooks delicate things without overcooking their outsides (poaching and steaming). It cooks vegetables, pasta and grains quickly and evenly (boiling). It turns the toughest, cheapest cuts of meat soft, given time (braising). And it holds a pot at a steady heat while a flavour builds (simmering). On the way you'll find out how much of a bottle of wine is still alcohol after a long braise, which matters to anyone at the table who avoids it, and you'll test three pieces of kitchen advice about pots of water.

Why water is gentle

Lesson 2 gave you two facts about water, and this lesson rests on both.

The first is its ceiling. Water at ordinary pressure can't get hotter than its boiling point: 100°C (212°F) at sea level, lower as you go up. FSIS puts the drop at "just under 1 °F" for every 500 feet, and draws the consequence: "foods that are prepared by boiling or simmering will cook at a lower temperature, and it will take longer to cook."³ Turn the flame up under a pot that is already boiling and you get more steam, not hotter water.

The second is that water hands over heat fast. Engineering ToolBox's ranges for the heat transfer coefficient, which lesson 2 used to explain why boiling water burns you and oven air doesn't, run from 0.5 to 1,000 for still air and from 3,000 to 100,000 for boiling water.² Put those together and you have a medium that delivers a lot of heat, but never more than about 100°C of it.

That's why water is called gentle and cooks evenly. The outside of the food cannot overshoot the water around it. A potato in boiling water has a surface at close to 100°C and a centre climbing towards it, and however long you leave it, no part goes past 100°C. It will fall apart eventually, but it won't burn. Compare lesson 2's point about a hotter oven: there the surface races ahead of the centre. In water, the surface is capped, so the gap between outside and centre is only as big as the water's temperature makes it.

The flip side is the thing lesson 6 was built on. Nothing wet browns fast, so food cooked in water doesn't take on a seared crust, however long it's in there. A braise that wants that colour and flavour gets it before the water goes in.

Boil, simmer, poach: the same water at different heats

These words are really a scale of temperature, and you can see where you are on it.

America's Test Kitchen (ATK) gives the two main marks on its page about boiling and simmering. A boil: "Liquid reaches 212 degrees ; large bubbles vigorously rise from bottom of pot and continually break surface." A simmer: "Liquid reaches 180 to 190 degrees ; small bubbles rise from bottom of pot and occasionally break surface."¹ (The stray spaces are on ATK's page.) In Celsius a simmer is about 82 to 88°C. Poaching sits below that. This course hasn't read a source that puts a number on poaching, so treat it as a working description: water that is hot and steaming, moving a little, with few or no bubbles breaking. Your thermometer can tell you where your own "poach" sits, and the practice section has you measure it.

So when do you want which? ATK gives its reasons for boiling: "flash-cooking (or blanching) vegetables so that they lose their raw edge while retaining their flavor and bright color; speeding up the cooking of grains such as brown rice or wheat berries, since surrounding the grains with boiling water transfers heat more quickly than the absorption method; and cooking pasta, where the agitation helps keep the pieces from sticking to each other."¹ Boiling is for speed, and for things that can take being thrown about.

Everything else gets a simmer, and ATK says why: "Less agitation means delicate foods won’t break apart and fats and soluble proteins in stock won’t coagulate and turn the liquid cloudy. Because lower burner temperatures allow time for heat to transfer evenly from the bottom of a pan to the top, there’s also less risk of scorching."¹ Three reasons, then: a boil knocks soft things to pieces, clouds a stock (lesson 10 comes back to that), and can catch on the bottom of a thick stew.

Poaching carries the same logic one step further, for food that sets at low temperatures and toughens as it goes past them. Lesson 5's eggs were the first case. Chicken and fish are the others you'll meet most.

A poached chicken breast, cooked to the rule

Lesson 4 opened with a gently poached chicken breast, to show that a temperature held over time kills germs as surely as a higher one reached for a moment. Here's how you'd actually cook one, and why the method makes the rule easy to hit.

You need a skinless chicken breast, a pot big enough to cover it with water or stock by a couple of centimetres, a few slices of ginger and a spring onion or two if you like, salt, and your thermometer.

1. Bring the liquid to a simmer, season it (lesson 3: taste it, since you'll eat the broth), and put the breast in. The cold meat will pull the temperature down.
2. Turn the heat down until the liquid sits below a simmer. This course's choice, not a source's, is about 80°C (176°F): hot enough to finish the job, low enough that the outside of the breast never gets much hotter than it needs to. Much cooler than that and the last few degrees take a long time, because the centre can only creep towards the temperature of the water around it (again this course's reading of lesson 2's physics, not a test). Check the liquid, not just the meat, with the thermometer.
3. Cook to your country's rule, measured in the thickest part. In the US, that is 165°F (73.9°C) for all poultry.⁸ In the UK, the FSA's rule is that "the middle of the food should reach a temperature of 70°C for 2 minutes" or one of its equivalents, and its cues for chicken are to "cut into the thickest part and check there is no pink meat left and that juices run clear".⁹
4. Lift it out and slice it. Keep the broth.

How long does it take? That depends on how thick your breast is (lesson 2's rule: twice as thick, about four times as long), so the thermometer decides, not the clock. What the low water buys you is a wide margin. In a hot pan, the outer layers of the breast keep cooking hard while the centre catches up, so a minute's inattention costs you. In water at 80°C, the outside cannot go past 80°C, so the gap between the outer layer and the 74°C centre is a few degrees, and a few extra minutes change little.

The broth is the other half of the dish. It now tastes of chicken, and dishes such as Hainanese chicken rice are built on exactly this: the bird poached, and the rice cooked in its broth. This course does not claim to know how that dish is "really" made; the point is the method, which cooks two things with one pot of water. Lesson 9 is about cooking rice in liquid, and lesson 10 about turning a broth into a stock, including how to cool a pot of it safely.

Steam: the same ceiling, faster delivery

Steaming cooks food in the vapour above boiling water rather than in the water. The temperature is the same: steam at ordinary pressure over a boiling pot sits at the boiling point. What changes is how it hands over heat. Lesson 2 showed that steam carries a large load of stored heat and releases it when it condenses on something cooler, and that condensing steam has the highest heat transfer coefficients on Engineering ToolBox's list, 5,000 to 100,000.² Boiling water's range is 3,000 to 100,000, so the two overlap. On this course's reading of those figures, steam hands over heat at roughly the rate boiling water does, at the same temperature, and the food isn't tumbling about in the water.

That's why steaming suits the same delicate things as poaching, and some sturdy ones too. A whole fish on a plate in a steamer, as in Cantonese steamed fish, cooks without being handled, and the plate collects its juices. Dumplings keep their shape. Greens soften without going waterlogged. For fish, the US rule is 145°F (63°C), "or cook until flesh is no longer translucent and separates easily with a fork", per foodsafety.gov.¹⁰ The UK's general rule, 70°C for 2 minutes in the middle of the food or an equivalent, is the FSA's for all food.⁹

Two practical points follow from lesson 2. Keep the water below the food and the lid on, because escaping steam carries heat away. And lift the lid away from you, tilting its far edge up first, because the cloud that comes out is the steam lesson 2 warned you about.

Tough meat, and why it needs time

A steak and a shin of beef are both muscle, and the reason one needs three minutes and the other three hours is what holds the muscle together.

Cuts such as a shoulder, a shin or a cheek have a lot of connective tissue around their muscle fibres, and collagen is what that tissue is chiefly made of. P. P. Purslow, reviewing the research in 2005, says the amount of connective tissue inside a muscle varies "with muscle position in the carcase and with animal age", and "This has long been recognised to influence the tenderness of cooked meat."¹⁹ Cooked briefly, that tissue stays tough. Cooked long enough in a wet pot, the collagen dissolves into gelatin, which is soft, gives a braising liquid its body, and is what lesson 10 uses to make a cold stock set.

The research this course read puts temperatures on the stages. In a 2005 review of what heat does to meat proteins, E. Tornberg of the Lund Institute of Technology gives the muscle proteins first: "Most of the sarcoplasmic proteins aggregate between 40 and 60 °C, but for some of them the coagulation can extend up to 90°C." The proteins of the muscle fibres themselves, tested in solution, gel at 45 to 50°C. Then: "At temperatures between 53 and 63°C the collagen denaturation occurs, followed by collagen fibre shrinkage. If the collagen fibres are not stabilised by heat-resistant intermolecular bonds, it dissolves and forms gelatine on further heating."⁵ This course has read that paper's abstract, not the whole review.

Two things follow from those figures, and together they're the whole logic of a braise. First, by the time collagen starts to give way, most of the muscle proteins have already set: nearly every figure in Tornberg's list for them is at or below 60°C. So a braised shin is, by steak standards, well done all through. What makes it tender is not the fibres staying soft but the collagen between them dissolving. (That is this course's reading of the two sets of figures side by side, not a claim the abstract makes.)

Second, the dissolving takes time. A 2019 study by M. E. Latorre, P. P. Purslow and colleagues cooked meat at 60°C for up to 24 hours and tested the connective tissue as it went. Its strength "diminished with cooking time", and they found "a slow and gradual increase in the proportion of denatured collagen".⁶ Their results, they write, support the idea that some of the collagen gives way easily and some resists. So at a steady temperature the change keeps going for hours, and it isn't finished when the meat is merely cooked through. The course has read the abstract of this paper too, not the full text.

Neither paper gives a braising time, and neither measures how much faster a hotter pot would be. Purslow's review says only that the connective tissue's contribution to toughness falls "at higher temperatures and longer cooking times",¹⁹ which is both, and gives no figure for trading one against the other. What the three do support is the rule the outline of every braise follows: bring the meat to a temperature where collagen gives way, then hold it there, and let time do the rest. Water is the natural way to hold it there, because a covered pot of liquid at a simmer stays at about 82 to 88°C for as long as you like without the surface of the meat drying out. FSIS says the same thing about slow cookers from the other direction: "The low heat helps less expensive, leaner cuts of meat become tender and shrink less."⁷

A beef braise with a bottle of wine

This is the shape most braises share, worked through with beef in red wine, the French version of the idea. A Chinese red-braised pork belly and a West African groundnut stew are other dishes of long, gentle cooking in a covered pot of liquid, each with its own order of steps; lesson 12 comes back to how a method carries across dishes.

You need about 1.5 kg of beef chuck or shin in large pieces, an onion, a carrot and some garlic, a 750 ml bottle of red wine, stock, salt and pepper, and a heavy pot with a lid.

1. Brown the meat, in batches. This is lesson 6 exactly: pat it dry, salt it, give the pieces room in a hot pan, and move each batch to a plate when it's brown. The colour and the fond come from this step, because nothing will brown once the liquid goes in.
2. Soften the vegetables in the fat left in the pot.
3. Deglaze with the wine, scraping up the fond, and bring it to the boil.
4. Add the meat back and enough stock to come most of the way up it, not over it.
5. Cover and hold at a gentle simmer, on the lowest hob setting that keeps it there or in a low oven. Check the liquid with your thermometer: you want ATK's 180 to 190°F, about 82 to 88°C.¹
6. Test it with a fork, from an hour in, every half hour. It's done when the fork slides into a piece and out again with no grip. That is a texture test, not a safety test: by then the meat has spent hours well above any temperature in lesson 4's table.
7. Taste and season at the end. A braise reduces as it cooks, so salt added at the start concentrates. Lesson 3's staged seasoning applies: season lightly at step 4, properly at step 7, and use acid if it tastes heavy.

For a meat-free braise of the same shape, use dried chickpeas, soaked, with the vegetables and stock, and test for creaminess rather than for give. The mechanism in beans is different (lesson 9 explains it). Keep kidney beans out of this, and that includes white cannellini: the FDA's chapter on the bean toxin says white kidney beans carry about a third as much as red ones,¹⁸ and a pot held at a simmer is not the boil lesson 9's rule asks for.

Now the question the wine raises.

How much of the alcohol is still there

Most people have been told that alcohol "cooks off". Some of it does. How much depends on how you cook it and for how long, and the best figures are in a table the US Department of Agriculture publishes for working out what's left in cooked food: the USDA Table of Nutrient Retention Factors, Release 6, from 2007. Its alcohol figures come from a study that tested, in the table's own words, "no heat application, alcohol added to a boiling liquid, flaming, and baking for various lengths of time".⁴

Here they are, as the percentage of the alcohol added that is still there.⁴

Three things in that table surprise people.

The first is the top row. Pour alcohol into something boiling and take it straight off the heat, and 85% of it is still there. A figure you'll often see repeated attaches 85% to flaming. That is a misreading: in the table, flaming is 75%.⁴ The flame looks dramatic and lasts seconds, and it goes out while most of the alcohol is still in the pan.

The second is the slope. It takes about two hours of simmering to get down to 10%, and even the longest time in the table, 2½ hours, leaves 5%. No row in the table reaches zero.

The third is what the percentages are of. They're shares of the alcohol you added, not the strength of the finished dish. This is what makes them usable: you can work out how much alcohol a serving holds.

Treat them as rough guides: each is one figure for a whole way of cooking, and the table can't know your pot. A wide pan uncovered loses alcohol faster than a narrow pot with a lid, on this course's reading of the physics, since evaporation happens at the surface open to the air; the table's rows don't separate them.

The braise, worked out

Take the beef braise above, with its whole bottle. Suppose the wine is 13.5% alcohol by volume (read your own label). Then the bottle holds 750 × 0.135, or about 101 ml of alcohol. Say the braise serves six.

Suppose you pulled it after 30 minutes, the time a quick stew might get. The table gives 35%: about 35 ml of alcohol left, or about 6 ml a serving, the alcohol in about 44 ml of the wine itself, three tablespoons or so, in each bowl.

Now suppose it took 2½ hours to get tender. The table gives 5%: about 5 ml left, or under 1 ml a serving, the alcohol in about 6 ml of the wine, a little over a teaspoon. And a braise that goes on past 2½ hours is off the end of the table, so the most you can say from it is "5% or less".

That's a small amount. It is not none. And whether it matters isn't a question this course can answer, because it depends on why the person at your table avoids alcohol. Some people avoid it for religious reasons, some because they're in recovery, some because of a medicine or a pregnancy, some because they simply don't drink, and each of those may draw the line in a different place. This course gives you the number and leaves the choice to the cook and the guest. The simplest respectful thing is to tell the guest what's in the dish and how long it cooked, and let them decide. A braise made without wine, with stock and a little of lesson 3's acid, is still a braise. What alcohol does to health is a question for Nutrition: The Evidence, lesson 10, not for this course.

Slow cookers

A slow cooker is a braise on a timer, and FSIS's page on them is clear about how it works and where it can go wrong. It cooks at a low temperature, "generally between 170° and 280° F", about 77 to 138°C, and "The direct heat from the pot, lengthy cooking and steam created within the tightly-covered container combine to destroy bacteria and make the slow cooker a safe process for cooking foods."⁷ Its rules follow from the one weakness in that design: the pot heats slowly.

"The slow cooker may take several hours to reach a safe, bacteria-killing temperature," FSIS says, which is why it wants ingredients kept in the fridge right up until they go in, so bacteria don't get what FSIS calls a head start "during the first few hours of cooking."⁷ It also says: "Always thaw meat or poultry before putting it into a slow cooker."⁷ The page does not give its reason next to that sentence. This course's reading is that the reason is the same slow start: a frozen block in a pot that already takes hours to get hot spends even longer passing through the temperatures where germs grow. It helps, FSIS adds, to set the cooker on high for the first hour if you can.⁷

Three more rules from the same page. Keep the lid on: "Keep the lid in place, removing only to stir the food or check for doneness." If the power goes out while you're away, "throw away the food even if it looks done"; if you're home, finish cooking it another way at once, on a gas hob, a grill outdoors or somewhere with power, and food that was fully cooked before the power went can stay safe "up to two hours in the cooker with the power off." And don't use one to reheat: "Reheating leftovers in a slow cooker is not recommended." Reheat on the hob, in the oven or the microwave to 165°F first; after that a preheated slow cooker can keep it hot "at least 140 °F".⁷ The FSA pages this course read give no slow-cooker rules of their own, beyond the one on raw red kidney beans that lesson 9 covers.¹⁷

That bean rule is also the best illustration of the slow start. The FDA's chapter on the bean toxin reports that slow-cooker casseroles "often reached internal temperatures of only 75°C or less, which is inadequate" to destroy it.¹⁸ Lesson 9 has the rest.

Pressure cooking: moving the ceiling

Everything so far has taken water's ceiling as fixed. A pressure cooker moves it. Seal a pot, and the steam from boiling water cannot escape, so the pressure inside rises, and with it the temperature at which the water boils. Utah State University Extension puts the principle in one line: "Steam temperature rises as the pressure is increased."¹⁶

How far? One maker, Instant Pot, gives its high-pressure setting as 10.2 to 11.6 psi (pounds per square inch above the air outside), and for one of its models "a working temperature of ~ 239°F to 244°F", which is about 115 to 118°C.¹⁴ The home-canning guidance from the National Center for Home Food Preservation gives the same relationship at a slightly higher pressure: canners "operated at 10 to 15 PSIG" reach "240° to 250°F", about 116 to 121°C.¹⁵ Those are about 15 to 20°C above the ceiling of an open pot, and moist heat at that temperature cooks braises, beans and stocks in less time. This course hasn't read a source that says how much less, so it does not give a figure. Follow the maker's manual for times.

It also answers the altitude problem, though not completely. FSIS's high-altitude figures mean an open pot in a mountain town boils several degrees below 100°C and cooks more slowly.³ A sealed pot raises the boiling point from wherever it starts, but on this course's reading of the physics, from a lower start it ends a little lower too, which fits canning guidance telling people at altitude to raise the pressure or the time.¹⁵ USU Extension adds a caution about electric models: its own study found they "don’t always work the same at high altitudes as at sea level", which it says isn't a problem when cooking a roast or chicken, because "the temperature of the food can be checked to make sure it is safe".¹⁶

The safety points are the maker's and the extension service's, not this course's:

• Don't overfill. Instant Pot says not to fill above two thirds, and not above half "When cooking foods that expand during cooking such as rice or dried vegetables", because overfilling "may cause a risk of clogging the steam release pipe and developing excess pressure."¹⁴
• Know the two ways of letting the pressure out. A quick release "will cause a jet of steam to eject through the top of the steam release handle", which is lesson 2's steam burn waiting to happen, so keep hands and face clear. The maker recommends letting the pressure fall on its own "for foods with large liquid volume or high starch content such as oatmeal, beans, porridge, and soups", because a quick release can make them spatter.¹⁴
• A pressure cooker is not a pressure canner. USU Extension's page is titled for exactly that, and its concern is that low-acid foods sealed in jars must reach a temperature you cannot check once the jar is closed.¹⁶ Home canning belongs to lesson 12 and the Emergency Preparedness course.

One contrast with the slow cooker is worth noticing. Instant Pot says frozen meat "can be cooked directly in the pressure cooker" with the time increased by about 50%, and that large frozen cuts "may add up to 45 to 60 minutes of preheating time."¹⁴ FSIS says the opposite for a slow cooker. The two statements come from different sources about different machines, one of which gets hot much faster than the other; this course reads that as the slow start again, but neither source compares them.

Three things people say about pots of water

"Salt makes the water boil faster"

It does the opposite, by an amount too small to notice. Salt dissolved in water raises its boiling point, and chemists calculate the rise from three numbers: a constant for the solvent, which for water is 0.513°C per mole of dissolved particles in each kilogram of water, from LibreTexts' reference table; the amount of salt; and the number of particles each unit of salt splits into, which for sodium chloride is two.¹¹¹²

Here's that worked out, as this course's arithmetic. Salt water at 1% by weight (10 g of salt in 990 g of water) holds about 0.17 moles of salt per kilogram of water, which is about 0.35 moles of particles. Times 0.513, that gives a rise of about 0.18°C. At 2% it's about 0.36°C. So heavily salted pasta water boils about a third of a degree hotter than plain water, and gets there a moment later, because it has that much further to climb. No one could taste the difference. Salt the water for flavour, which is lesson 3's reason and lesson 9's, and not for speed.

"Start with hot water from the tap, it saves time"

It does save heating time. That part is simple physics, and this course's arithmetic, ignoring heat lost along the way: water from a hot tap at, say, 50°C has 50 degrees to climb to the boil, and water from a cold tap at 10°C has 90, so the hot water needs a little over half the energy, and on the same burner a little over half the time. (The folk version, that cold water boils faster, is just wrong.)

The reason not to do it is lead, not speed. The US Environmental Protection Agency: "Hot water dissolves lead more quickly than cold water and is therefore more likely to contain greater amounts of lead." Its advice follows: "Never use water from the hot water tap for drinking, cooking, or making baby formula."¹³ So fill the pot from the cold tap and, if you're in a hurry, boil some of the water in a kettle.

"Just put it in the slow cooker frozen"

FSIS's rule is to thaw meat and poultry first, and the page's reasoning about slow cookers' slow start is the context for it (see above).⁷ Lesson 4 gave the safe ways to thaw: FSIS lists the fridge, cold water changed every 30 minutes, and the microwave, and the FSA the fridge or the microwave's defrost setting just before cooking. A pressure cooker is a different machine, and its maker's instructions for frozen meat are its own.¹⁴

The course's question from lesson 1 fits all three. "Salt the water" protects flavour and has nothing to do with speed. "Use cold water" is really about lead. "Thaw before the slow cooker" protects against a slow start, and applies to the machine it was written for.

What people get wrong

"The alcohol cooks off." Some does. The USDA's table runs from 85% remaining (stirred into something boiling, off the heat) to 5% (simmered 2½ hours), and never reaches zero.⁴

"Flaming burns off most of the alcohol." The table gives 75% remaining after flaming.⁴ The widely repeated "85% when flamed" belongs to a different row.

"Salt makes water boil faster." It raises the boiling point by a fraction of a degree, so it boils a moment later.¹¹¹²

"Start with hot tap water." It's quicker, and the EPA says not to, because of lead.¹³

"A hard boil is the way to hurry a braise." It adds 12 to 18°C at most and a lot of agitation, and dries the outside. The research read here shows time doing most of the work at a steady temperature, and gives no figure for how much a boil would save.⁶¹⁹

"Put it in the slow cooker frozen." FSIS says thaw meat and poultry first.⁷

"A braise is done when it's cooked through." It's safe then, but it isn't tender until the collagen has had time to dissolve.⁶

Practice

Connections

Lesson 2 gave you water's ceiling and its fast delivery of heat; this lesson turned them into a scale of methods, from a boil for speed to a poach for margin. Lesson 4's time-and-temperature rule is what the poached chicken was cooked to, and its cooling rules end the braise. Lesson 6's browning and deglazing are the first steps of every braise, and the wine you deglazed with there now has a number attached. Lesson 3's staged seasoning is why a braise is salted at the end.

Lesson 9 cooks starches in water: rice by absorption and in plenty of water, beans (including the red kidney bean rule), and pasta in less water than you've been told. Lesson 10 takes the broth from the poached chicken and the gelatin from the braise and makes stock, and explains why a big pot has to be cooled with care.

Go deeper

• America's Test Kitchen, "Cooking Class: Boil versus Simmer". Short enough to read in two minutes, with the two definitions and ATK's reasons for choosing each.
• USDA, Table of Nutrient Retention Factors, Release 6 (2007). The whole table was read for this course. The alcohol rows are in food group 14; the rest of the table does the same job for vitamins and minerals, if you want to see how the US government estimates what cooking removes.
• USDA FSIS, "Slow Cookers and Food Safety". Read in full. One page, every rule above, with the reasons FSIS gives.
• Utah State University Extension, "Why Electric Pressure Cookers Are Not Pressure Canners". Read in full. What the pressure numbers mean, and why cooking and canning ask different things of them.

Sources

1. America's Test Kitchen, "Cooking Class: Boil versus Simmer", Cook's Illustrated how-to, no author or date, https://www.americastestkitchen.com/cooksillustrated/how_tos/10660-cooking-class-boil-versus-simmer . Read level: full, directly. Supports: the boil and simmer definitions with their temperatures and bubbles, when ATK boils (blanching, grains, pasta), and its three reasons for simmering. The Celsius conversions and the poaching description are this course's, as the body says.
2. Engineering ToolBox, "Convective Heat Transfer", https://www.engineeringtoolbox.com/convective-heat-transfer-d_430.html . Read level: the coefficient list, directly. Supports: the ranges for air, boiling water and condensing steam.
3. USDA FSIS, "High Altitude Cooking", last updated 13 August 2024, read through the Internet Archive's capture of 23 September 2026 . Read level: full. Supports: the drop of just under 1°F per 500 feet and the slower cooking of boiled and simmered food.
4. USDA Agricultural Research Service, Nutrient Data Laboratory, USDA Table of Nutrient Retention Factors, Release 6, December 2007, https://www.ars.usda.gov/ARSUserFiles/80400530/pdf/retn06.pdf . Read level: full (PDF text extracted). Supports: every figure in the alcohol table and the quoted description of what was tested. The underlying study is cited through this table; this course did not read it. The arithmetic for the braise, the 13.5% strength and six servings are this course's; the point about pot width and lids is this course's reading, as the body says.
5. E. Tornberg, "Effects of heat on meat proteins - Implications on structure and quality of meat products", Meat Science 70(3), 2005, 493-508, doi 10.1016/j.meatsci.2004.11.021 . Read level: abstract only, directly. Supports: the sarcoplasmic and myofibrillar protein ranges, the collagen denaturation range, shrinkage, and dissolving into gelatine. The reading that the muscle fibres have set before the collagen gives way is this course's, as the body says.
6. M. E. Latorre, M. I. Palacio, D. E. Velázquez and P. P. Purslow, "Specific effects on strength and heat stability of intramuscular connective tissue during long time low temperature cooking", Meat Science 153, 2019, 109-116, doi 10.1016/j.meatsci.2019.03.016 . Read level: abstract only, directly. Supports: cooking at 60°C for up to 24 hours, strength falling with time, the slow and gradual increase in denatured collagen, and the easily destabilised and more resistant fractions.
7. USDA FSIS, "Slow Cookers and Food Safety", last updated 8 August 2013, read through the Internet Archive's capture of 23 September 2026 . Read level: full, directly. Supports: the temperature range, tender leaner cuts, the safety of the process, the slow start and the head start, thawing, the first hour on high, the lid, the power-cut rules (including finishing the cooking another way when you're home), reheating, holding at 140°F, and refrigerating leftovers within two hours. That the thawing rule rests on the slow start is this course's reading, as the body says.
8. USDA FSIS, "Safe Minimum Internal Temperature Chart", last updated 14 April 2025, read through the Internet Archive's September 2026 capture . Read level: full. Supports: 165°F (73.9°C) for all poultry.
9. Food Standards Agency, "Cooking your food", GOV.UK, https://www.gov.uk/government/publications/cooking-your-food/cooking-your-food . Read level: full. Supports: 70°C for 2 minutes in the middle of the food, and the visual cues for chicken.
10. foodsafety.gov, "Cook to a Safe Minimum Internal Temperature", last reviewed 21 November 2024, read through a 2026 Internet Archive capture . Read level: full. Supports: fish at 145°F (63°C) or until no longer translucent and flaking with a fork.
11. LibreTexts, "B5: Ebullioscopic (Boiling Point Elevation) Constants", Chemistry LibreTexts reference tables, public domain . Read level: the table, directly. Supports: water's constant, 0.513.
12. LibreTexts, Introductory Chemistry, 13.9, "Freezing Point Depression and Boiling Point Elevation" . Read level: the relevant section, directly. Supports: the formula and sodium chloride splitting into two particles. The 1% and 2% figures are this course's arithmetic, as the body says.
13. US Environmental Protection Agency, "Why can't I use hot water from the tap for drinking, cooking, or making baby formula?", last updated 28 October 2025 . Read level: the answer, directly. Supports: the quotation. The heating-time comparison is this course's arithmetic, as the body says.
14. Instant Pot, "Frequently Asked Questions", https://instantpot.com/pages/frequently-asked-questions . Read level: the pressure-cooking answers, directly. A manufacturer's page. Supports: the pressure levels, the working temperature for one model, the fill lines, quick and natural release, and frozen meat.
15. National Center for Home Food Preservation, "Ensuring Safe Canned Foods", https://nchfp.uga.edu/how/can/general-information/ensuring-safe-canned-foods/ . Read level: full, directly. Supports: 240 to 250°F at 10 to 15 PSIG, and raising time or pressure at altitude.
16. Cathy Merrill, Karin Allen and others, "Why Electric Pressure Cookers Are Not Pressure Canners", Utah State University Extension . Read level: full, directly. Supports: steam temperature rising with pressure, the altitude finding and its limited relevance to cooking, and the difference between cookers and canners.
17. Food Standards Agency, home food fact checker, GOV.UK . Read level: full. Supports: not slow-cooking raw red kidney beans. The statement that the FSA pages read give no other slow-cooker rule is about this course's reading, not the FSA's.
18. US Food and Drug Administration, Bad Bug Book, 2nd edition, 2012, chapter "Phytohaemagglutinin (kidney bean lectin)", https://www.fda.gov/media/83271/download . Read level: full chapter. Supports: slow-cooker casseroles often reaching only 75°C or less, and white kidney beans carrying about a third of red kidney beans' toxin. That cannellini are white kidney beans rests on University of Illinois Extension, Lisa Peterson, "Kidney Beans and Slow Cookers", 29 February 2024, https://extension.illinois.edu/blogs/live-well-eat-well/2024-02-29-kidney-beans-and-slow-cookers, which writes of "Raw white (cannellini) kidney beans" (read level: the sentence quoted, directly; lesson 9 cites it in full).
19. P. P. Purslow, "Intramuscular connective tissue and its role in meat quality", Meat Science 70(3), 2005, 435-447, doi 10.1016/j.meatsci.2004.06.028 . Read level: abstract only, directly. Supports: the amount of connective tissue varying with muscle position and animal age, its long-recognised effect on the tenderness of cooked meat, and its contribution falling at higher temperatures and longer cooking times. That shoulder, shin and cheek are among the cuts with more of it is this course's general knowledge, not the abstract's.