Cooking without a recipe: ratios and a week of meals

Here's a recipe card of the kind you'll find anywhere. "Heat the wok for 1 minute. Add the prawns and stir-fry for 2 minutes. Add the broccoli and pepper and stir-fry for 3 minutes. Add the sauce and cook for 1 minute more." It reads like a set of facts, but it's a report of what happened in one kitchen, with one burner, one pan, broccoli cut to one size and prawns that started at one temperature. Change any of those and the minutes stop being true, while the dish still works, because the dish was never really in the minutes.

This lesson is about where the dish is. The first half takes recipes apart into what travels and what doesn't, so that you can cook without the card and change it to suit what's in the fridge. The second half plans a week of meals around a handful of techniques, and that's where lesson 4's food-safety rules do their most practical work: food cooked once and eaten three times has to be cooled, stored, frozen, thawed and reheated, and the US and the UK have different rules for most of those steps.

What a recipe is made of

Lesson 1 gave you the course's question: what is this rule protecting, and does it apply here? This lesson asks it of recipes, which are rules in a row, and sorts what's in them into four kinds.

The method. The order of the steps, and each step's reason. "Brown the meat in batches" is lesson 6's dry surface. "Simmer, covered, until tender" is lesson 8's collagen. These travel, because each rests on a mechanism, and the mechanism works the same in any kitchen.

The ratios. How much of one thing to how much of another: two parts egg to three of flour, three of oil to one of vinegar. These travel too, and they scale. Double everything and a ratio stays true, which is why bakers write bread as percentages (lesson 11).

The tasting points. The moments where a cook stops and decides: is it salted enough, does it need acid? A good recipe marks them ("taste and adjust"); many leave them out.

The numbers for one kitchen. Minutes, "medium heat", "a large onion", "1 teaspoon salt". These are the writer's measurements of their own food, and they don't travel. Lesson 2's thickness rule is why for times, and lesson 3's salts, one nearly twice as salty as another by the spoon, are why for salt. America's Test Kitchen (ATK) gave the general reason in lesson 9: "set-in-stone ratios fail the home cook", because evaporation depends on "the size and shape of the cooking vessel, how tightly the pot is covered, and the source and intensity of the heat."²⁰

Professional schools start here too. The Culinary Institute of America's first course, Culinary Fundamentals, lists tasting first and promises "an introduction to the concepts of ratios and formulas".¹

A stir-fry, taken apart

Here's the recipe from the top of the lesson in full. It's written for this lesson, in the shape most stir-fry recipes take, so that it can be taken apart; it isn't anyone's tested recipe, and nothing here claims it is how the dish is made anywhere in particular.

Prawns with broccoli and pepper (serves 2). 300 g raw peeled prawns. 1 head of broccoli, in florets. 1 red pepper, sliced. 2 cloves of garlic and a thumb of ginger, minced. 3 spring onions, sliced. For the sauce: 3 tablespoons soy sauce, 4 tablespoons water, 1 tablespoon rice wine, 1 teaspoon sugar, 1½ teaspoons cornstarch. 1 teaspoon sesame oil. Heat the wok for 1 minute. Add oil and the prawns and stir-fry for 2 minutes. Add the broccoli and pepper and stir-fry for 3 minutes. Add the garlic, ginger and sauce and cook for 1 minute. Stir in the sesame oil and spring onions. Serve with rice.

Read it with this course behind you and three problems show up.

The first is the pan. The recipe assumes a wok, and most home cooks have a frying pan. ATK's technique for stir-frying without one warns that "Even a skillet set over high heat won’t get hot enough to quickly stir-fry either large amounts or large pieces of food", and says: "If necessary, cook the protein in batches to avoid overcrowding the pan, which will cause the protein to steam rather than sear."⁸ This course's reading is that 300 g of cold prawns in one go is the large amount ATK means, and the likely result is lesson 6's puddle.

The second is the times. "2 minutes" for the prawns means nothing without their size and how cold they were. What the prawns need is to be done, and the two countries describe it in almost the same words: in the US, cook shellfish "until flesh is pearly or white, and opaque"; in the UK, "prawns, scallops, crab, and lobster flesh should become firm and opaque".⁹¹⁰ The broccoli and the thinner, softer pepper get the same 3 minutes, and lesson 1's rule says they can't both finish on time unless they were cut to match. And "1 minute" for the sauce is shorter than ATK found cornstarch needs: "a couple of minutes to achieve maximum thickness".⁷

The third is what's missing. There's no tasting point. Three tablespoons of soy sauce carry most of the dish's salt, and nobody tastes the sauce until it's on the plate.

The same recipe, as a method

Rewrite it as what it is: lesson 6's stir-fry method, a sauce built to a ratio, and two tasting points.

1. Everything ready before the heat goes on (lesson 1): broccoli florets cut smaller than the soft pepper strips, so they finish together, and the sauce mixed cold with the cornstarch stirred in, which is the slurry ATK describes: "first mix it with cold liquid to form a slurry before adding the thickener to hot liquids to prevent clumping."⁷
2. Taste the sauce now, while you can still fix it: acid if it is flat and heavy, water if it's too salty (lesson 3).
3. Dry the prawns and cook them in batches until opaque and firm, and set them aside.
4. Vegetables next, hardest first, then the aromatics briefly. Test a piece; do not count minutes.
5. Prawns back, sauce in (give it a stir first), and toss until it bubbles and thickens, a couple of minutes. Taste again, and adjust.

Now the ratio. The sauce is 8 tablespoons of liquid, which is half a cup, with 1½ teaspoons of cornstarch, which is half a tablespoon. That's the proportion lesson 10 took from Michael Ruhlman's cornstarch-thickened sauce: about a tablespoon of cornstarch to a cup of liquid, by this course's division of his recipe.⁶ So what you carry away is not "3 tablespoons of soy sauce". It's half a cup of seasoned liquid for two, a tablespoon of cornstarch per cup, tasted before it goes in.

Tofu, cubed and patted dry, goes where the prawns went for a meat-free version.

Ratios: the part of a recipe that travels

Michael Ruhlman built a book on this idea, Ratio: The Simple Codes Behind the Craft of Everyday Cooking (2009). This course has read the book's catalogued contents, its publisher's description and Ruhlman's own blog posts, not the book itself. The description puts the claim plainly: "When you know a culinary ratio, it’s not like knowing a single recipe, it’s instantly knowing a thousand."² The catalogue says the book gives thirty-three ratios and has a section called "The all-important scale": his ratios are by weight.²

Here are the ones this course has seen, and where.

The last three are how the book's publisher describes it, which isn't the book, so treat them as the book's figures at second hand. Ratios for stock and pie dough are also attributed to the book, but this course hasn't found either on a page by Ruhlman or his publisher, so it does not print them as his.

Anchoring a ratio to what you have

A ratio is most useful when one ingredient is fixed and you build the rest around it. Ruhlman's pasta post puts it in one line: "once you have the pasta ratio, you can make pasta using one egg, two, or three, or more. Just weigh them, 2 parts egg, 3 parts AP flour."³ (AP is all-purpose flour, plain flour in the UK.) In a reply to a reader who asked about shells, he added: "always weigh them out of the shell".³

So crack one egg into a bowl on your scale. Say it weighs 57 g. The flour is one and a half times that, 57 × 1.5, which is about 86 g. That's the whole recipe, and it fits whatever egg you happened to have, which a recipe that says "1 large egg, 100 g flour" cannot do. His post kneads the dough until smooth, about 10 minutes, and rests it covered for 20 minutes to an hour; lesson 11 explained what that does to the gluten.³

The pancake post makes the same point: ratios "scale to what you have or need. Say you have only one egg."⁴ His ratio is 2 parts liquid, 1 of egg, ½ of butter and 2 of flour, and he calls the result "a fairly thick batter", to be thinned with an ounce or two more milk if you like. So the ratio is a starting point, and he adds: "No matter how many times I make pancakes, I always check the ratio."⁴

Ratios you already have

You've met a ratio in most lessons of this course. Here they are in one place, each with the kind of source behind it.

Look at the right-hand column. One row is a test; the rest are a cook's proportion, or this course's arithmetic from a cook's recipes. That's normal. Asked whether bread's percentages have firm rules, Martin Philip of King Arthur answers: "Unfortunately, the answer is no."²¹ A ratio is where you start, and the tasting points are where you make it yours.

What a recipe's rules are protecting

Turn the course's question on a recipe's instructions one at a time, and most fall into one of two groups.

Cooking rules protect a result you can check yourself: a texture, a colour, a flavour. "Cook the beef in two batches" protects a dry surface (lesson 6). "Add the tomatoes once the beans have softened" protects beans from acid, which slows softening (lesson 9). If you know what one of these protects, you can change it for your kitchen, and the dish will tell you whether you were right.

Safety rules protect against something you can't see, smell or taste, so the dish cannot tell you whether you got them right. "Boil the soaked kidney beans for at least 30 minutes" protects you from a toxin (lesson 9). "Cool the stew in shallow containers" protects against Clostridium perfringens (lesson 10). These come from regulators, and they travel exactly as they are.

A recipe prints both kinds in the same voice, as though "simmer for 20 minutes" and "boil for 30 minutes" were the same sort of sentence. Telling them apart is most of what reading a recipe for its method means.

The UK's Food Standards Agency (FSA) seems at first to say something different. Its cooking page says: "When following a recipe take care to follow the instructions for cooking times and temperatures carefully."¹⁰ Its first top tip is to "always follow cooking temperature guidelines according to the recipe or packet instructions carefully".¹⁰ Taken at its word, that is advice to trust the recipe's clock. The sentence sits under the page's table of safe temperatures and times, though, and the same page tells you to check that food is cooked with a thermometer or by cues such as steaming hot and no pink, not by the clock. This course's reading is that the FSA is warning against cutting a time short, and that it and this lesson agree on the part that matters: a recipe's time is where you start, and the check is what tells you the food is done.

When to follow the recipe to the letter

A few recipes are the whole point of not adapting, and they share a feature: what goes wrong can't be tasted, seen or smelled, and the only protection is a method someone has tested.

Home canning. The CDC's page on home-canned foods is the most direct instruction in this course: "Use only recipes and cookbooks that follow the steps in the USDA guide." "Do not use other recipes, even if you got them from a trusted friend or family member."¹⁴ And it says why the usual checks are useless: "You cannot see, smell, or taste the toxin that causes botulism."¹⁴ This course doesn't teach canning; Emergency Preparedness covers keeping food for the long term, and the USDA's guide is where to start.

Flavoured oils kept at room temperature. Lesson 3's garlic oil lives in the fridge, "for no more than 4 days".¹⁵ The tested method for one that keeps out of it, from the University of Georgia, warns: "Do not replace the citric acid solution with vinegar or lemon juice, as they have not been tested and may result in an unsafe final product."¹⁶ There the ratio is itself the safety rule.

A regulator's time or temperature written into a recipe. The kidney bean boil is one; the 160°F for egg dishes in the US (lesson 5) is another. You can change everything around them, but not them.

A stir-fry that's a little too salty tells you, and you add water next time. A home-canned jar of green beans that went wrong tells you nothing.

Planning a week from a few techniques

If you know five techniques well, you don't need a new recipe for every night. You need a plan that uses the same few techniques in different combinations, with some things cooked once and eaten more than once. That's batch cooking, and every batch is a leftover, which is where the two countries' rules differ most.

Time Management's lesson on a week that survives put the fixed points in first and reserved slack before anything else. This course applies that order to food: the evenings you cannot cook first, then the batch cooking on the day you have time, then quick dinners that use what the batch made, and one dinner left loose for the night the week goes wrong.

A batch item is anything cooked in quantity once and used across several meals: a braise (lesson 8), a pot of beans or rice (lesson 9), a stock (lesson 10). Each needs a storage plan, written before you cook, with five lines:

1. How it cools. Into shallow containers no more than about 5 cm (2 inches) deep (lesson 10). In the US, into the fridge within 2 hours, hot if you like; in the UK, cooled first and in the fridge within one to two hours. Cooked rice in the UK is cooled faster, ideally within an hour (lesson 9).
2. How long it keeps in the fridge. 3 to 4 days in the US; 48 hours in the UK, and cooked rice no more than one day (lessons 4 and 9).
3. What gets frozen, and when.
4. How it thaws.
5. How it's reheated. In the US to 165°F (74°C), with sauces, soups and gravies brought to a rolling boil; in the UK until steaming hot, and only ever once (lesson 4).

The next section works a week through, and it is built to fail under one country's rules.

A Sunday braise and a Monday pot of rice

Here's a week for a household of two, from five techniques: a braise, rice by absorption, a stir-fry, a tray of roasted vegetables and a vinaigrette. On Sunday afternoon you braise about 1.5 kg of pork shoulder with onions and stock (lesson 8's method); for a meat-free version, soaked chickpeas braised with the same vegetables, as lesson 8 did, and not kidney beans of any colour. It makes about eight portions, four dinners for two. On Monday you cook a pot of rice.

Under the US rules

The plan works as written, provided the cooling does: shallow containers into the fridge within 2 hours, hot if need be, and each reheat to 165°F, with the braise's liquid brought to a rolling boil, FSIS's rule for "sauces, soups and gravies".¹³ Thursday is the braise's last day, so if anything slips, it has run out of days. FSIS says to "Freeze leftovers within 3-4 days", and freezing the Thursday portion on Sunday takes the pressure off the end of the week.¹²

Under the UK rules, and the freezer that fixes it

The fix is to make the freezer do what the fridge can't. The FSA calls a freezer "a pause button", and says that leftovers "should be frozen as soon as possible".¹¹ Here's the week, day by day.

• Sunday. As soon as dinner is served, divide the rest of the braise into three tubs of two portions, not one pot. The FSA says freezing in individual portions "will help you defrost only what you need", and each tub can then be reheated once.¹¹ Cool them, since the FSA wants warm dishes cooled before they go in the freezer, and within two hours of cooking put Monday's tub in the fridge and Wednesday's and Thursday's in the freezer, flat if you can.¹¹ Label each with what it is and the date.
• Monday. Monday's tub, reheated once until steaming hot: about 24 hours after cooking, well inside the 48. Cook the rice, and get the leftover rice cold within the hour, spread thin (lesson 9). Tuesday's share goes in the fridge. For Thursday, either plan a fresh pot or put a second share in the freezer, also within an hour of cooking.¹⁷
• Tuesday. Fried rice, heated until steaming hot all the way through. It's about 24 hours after the rice was cooked, which is the limit, so it cannot slip to Wednesday. It's also the rice's one reheat, so nothing of it is kept. After dinner, move Wednesday's braise from the freezer to the fridge.
• Wednesday. The braise has had about a day in the fridge. FSIS's thawing page, the only source read here with a thawing time, gives a pound of minced meat or boneless chicken breasts "a full day";²² a flat portion should be quicker than a deep one (this course's reasoning, below). Before you reheat it, check that it's thawed right through to the middle, because the FSA says "Partially defrosted food may not cook evenly and this means that harmful bacteria could survive the cooking process."¹¹ If it is not, finish it in the microwave on the defrost setting and reheat it straight away. The FSA gives the microwave as its other defrosting route, "directly before cooking"; using it to finish a slow fridge thaw is this course's application of that.¹¹ Reheat once, until steaming hot. Because it went into the fridge only a day ago, it is inside the FSA's 24 hours after defrosting. After dinner, move Thursday's tub to the fridge.
• Thursday. The braise as Wednesday. The rice is a fresh pot, twenty minutes' work, or the frozen share, moved to the fridge on Wednesday evening and, in the FSA's words, reheated "until it is steaming hot before eating immediately".¹⁷

It's the same week, the same food and the same techniques. What changed is when things went into the freezer, and that was decided on Sunday, before the first portion was eaten. That's why the storage plan is written before you cook, and why the thawing is timed to the evening before: move a tub too early and the 24-hour clock can run out before you eat it.

What the freezer does, and what it does not

Both countries agree on what makes a batch plan work. FSIS, on its freezing page: "Food stored constantly at 0 °F will always be safe. Only the quality suffers with lengthy freezer storage."¹² The FSA, on its page about chilling and freezing: "A freezer acts as a pause button - food in a freezer won’t go bad and most bacteria cannot grow in it."¹¹ (0°F is about -18°C, the figure the FSA gives for a freezer.)

Pause is the right word, because freezing doesn't kill germs (lesson 4). Once thawed, FSIS says, "you must handle thawed items as you would any perishable food."¹² The two countries then set different clocks. FSIS's leftovers page says of frozen leftovers thawed in the fridge: "After thawing, the food should be used within 3 to 4 days or can be refrozen."¹³ The FSA says to use food "within 24 hours after it’s been fully defrosted".¹¹

Freezer times are for quality

The storage times both regulators give are about how good the food will be, not whether it is safe. FSIS: "Because freezing keeps food safe almost indefinitely, recommended storage times are for quality only." Its chart gives soups and stews 2 to 3 months.¹² The FSA says "Meats are usually best eaten within 2-3 months", and that freezer burn affects quality, "rather than the safety".¹¹ FSIS's leftovers page gives frozen leftovers 3 to 4 months, a month more than its own chart,¹³ which tells you how precise these figures are meant to be.

Freeze it flat and fast

FSIS says to freeze food as fast as possible, for quality: "Ideally, a food 2-inches thick should freeze completely in about 2 hours." And: "Never stack packages to be frozen. Instead, spread them out in one layer on various shelves, stacking them only after frozen solid."¹² That's lesson 2's thickness rule again: a thin, flat package loses its heat far faster than a deep one, so the same 5 cm that cools a stew safely in the fridge freezes it quickly. By the same physics a flat bag should thaw faster too, which helps with the UK's one-day clock; that last point is this course's reasoning, not a figure from a source.

Some things do not freeze well. FSIS names "mayonnaise, cream sauce and lettuce", and gives the reason for the first two on the same page: slow freezing makes large ice crystals, and "Emulsions such as mayonnaise or cream will separate and appear curdled."¹² Those are lesson 5's emulsions. So in a batch week, freeze the braise and the stock, and make the salad and its dressing on the day.

Refreezing

"Never refreeze anything that has thawed" is one of the most repeated kitchen rules, and the US regulator does not say it. FSIS: "Once food is thawed in the refrigerator, it is safe to refreeze it without cooking, although there may be a loss of quality due to the moisture lost through thawing. After cooking raw foods which were previously frozen, it is safe to freeze the cooked foods."¹² The limits are in the same passage: nothing left out of the fridge longer than 2 hours, or 1 hour above 90°F (32°C), goes back in, and food thawed in cold water or the microwave is cooked before it's refrozen.¹²¹³

The UK page read for this course says less. It allows the second case: "you can freeze food again once cooked, but you’ll only be able to reheat it once after that".¹¹ It doesn't say whether raw food thawed in the fridge can be refrozen raw, so this course gives no UK rule for that. If you're in the UK, cooking it and then freezing it is the route the page does cover.

FSIS also allows reheating a casserole straight from frozen, which "will take approximately one and a half times as long".¹² The FSA page gives no rule on that; its advice is to defrost fully first, for the reason in Wednesday's step.¹¹

Cooking for other people

A batch cooked for a household, or taken to a friend, carries lesson 4's two extra hazards into every portion.

Allergens. Heat does not remove an allergen, and scraping it off a plate isn't enough; the FSA says "an extremely small amount can be enough to cause an allergic reaction."¹⁸ So if anyone eating the week has a food allergy, decide before you cook whether the whole batch leaves the allergen out, or their portion is made first with clean tools and a clean pan. Ask them first, since your guest "will have the best understanding of their specific allergy", and label each tub with what went in as well as the date, which is the FSA's advice on "keeping a note of the ingredients or the food packet itself used in the dish".¹⁸ A stir-fry sauce made in bulk with soy sauce and sesame oil puts two allergens from both countries' lists into every portion. Those steps for a batch plan are this course's application of the FSA's advice.

Someone at higher risk. Lesson 4's callout applies to every batch, including its rule on runny eggs if the fried rice gets a fried egg on top. Lesson 4 also showed that Listeria grows in the fridge, and that heating a chilled food until steaming hot deals with it in both countries' advice. This course's application of that to your own leftovers is to serve them to someone in these groups reheated until steaming hot, not cold.

The label, not your nose. Every tub gets a date, and the date decides, not the smell. FSIS says the germs that make people ill "do not generally affect the taste, smell, or appearance of a food. In other words, one cannot tell that a pathogen is present."¹⁹ The FSA's advice to "label food you freeze so you don’t end up with Unidentified Frozen Objects (UFOs)" is a joke with a serious end:¹¹ an unlabelled tub has no clock.

The course project: "A week from five techniques"

The course ends with a project that puts all of this together. You choose no more than five techniques, plan and cook a week of dinners from them with at least two batch items, write the storage plan for your own country, and cook one dinner from its method and a ratio alone. The full brief and the rubric are in the course's assessments, under "A week from five techniques". The second exercise below is a first run at its planning.

What people get wrong

"Good cooks don't measure." The Culinary Institute of America teaches "ratios and formulas" in its first course,¹ Ruhlman checks his pancake ratio every time,⁴ and bread is written by weight because salts differ spoon for spoon (lesson 11). What's true in the saying is lesson 3's point: you can taste your way back in a soup, and you can't in a dough, so measure the dough.

"Leftovers are good for a week." Not under either country's rules: 3 to 4 days in the US, 48 hours in the UK, and one day for cooked rice in the UK.¹³¹⁰¹⁷ The freezer is how a batch lasts a week.

"Never refreeze anything that has thawed." FSIS says food thawed in the fridge can be refrozen uncooked, with some loss of quality. The limit is food that has been left warm.¹² The FSA page read here allows refreezing once the food is cooked.¹¹

"A recipe's cooking time is a fact." It's the writer's measurement of their own food in their own pan (lesson 2). Test the food. Safety times are the exception, because they're rules, not estimates.

Practice

Connections

Every earlier lesson is in here: lessons 1 and 6 in the stir-fry's method, 2 and 3 in why times and spoons don't travel, 4 in the storage plan, 8 to 10 in the batch items and ratios, 11 in a ratio made exact. Time Management gave the week its order, fixed points and slack first, and the written prediction of where it'll break. Habits and Self-Discipline adds that a stable cue does work that motivation doesn't; this course's reading is that a batch cook every Sunday afternoon needs less deciding each week, which applies that research to a kitchen rather than reporting a finding about cooking.

After this course, First Aid and CPR, later this term, treats the burns and cuts this course only prevents, and Emergency Preparedness covers keeping food through a power cut. What to put in your week is the question Nutrition: The Evidence took on; this course has made no claim about what's healthy to eat, and it does not start now.

Go deeper

• Michael Ruhlman, "Pancake Ratio". Read in full for this course. A short post that shows a ratio scaled to whatever you have. His book Ratio is the next step; this course has read only its contents list and its publisher's description.
• USDA FSIS, "Freezing and Food Safety", and FSA, "How to chill, freeze and defrost food safely". Both read in full. Each country's rules on freezing, thawing and refreezing on one page.

Sources

1. The Culinary Institute of America, "CULS-100 Culinary Fundamentals", course description, https://catalog.ciachef.edu/culinary-skills/culs100 . Read level: full, direct. Supports: tasting listed first, and "ratios and formulas".
2. Michael Ruhlman, Ratio: The Simple Codes Behind the Craft of Everyday Cooking (Scribner, 2009): the University of Wisconsin–Madison catalogue record, and the publisher's description on Goodreads, https://www.goodreads.com/book/show/3931154-ratio . Read level: the catalogued contents and the publisher's description, direct; the book itself was not read. Supports: thirty-three ratios, the scale, the quoted lines, and the vinaigrette, biscuit and cookie ratios, labelled in the body as the description's. The stock and pie dough ratios were not found on a page read here.
3. Michael Ruhlman, "Pasta: 'Agnolotti' (and the power of ratios)", ruhlman.com, 13 February 2013, https://ruhlman.com/pasta-agnolotti-and-the-power-of-ratios/ . Read level: full, direct, with the comments. Supports: 2 parts egg to 3 of flour, the kneading and resting, and the reply about shells (a comment signed by Ruhlman).
4. Michael Ruhlman, "Pancake Ratio", ruhlman.com, 3 February 2014, https://ruhlman.com/pancake-ratio/ . Read level: full, direct. Supports: the ratio, its source in the book, the recipe's flour, scaling, the thick batter, and checking the ratio. The checkpoint's grams are this course's.
5. Michael Ruhlman, "Bake Your Own 5:3 Bread", ruhlman.com, 27 March 2013 . Read level: full, direct. Supports: 5 parts flour to 3 of water.
6. Michael Ruhlman, "Holiday Classic: Gravy & Cranberry Sauce" and "Egg Foo Young", ruhlman.com . Read level: full, direct. Supports: the roux's 3:2 as his stated ideal, and the cornstarch sauce whose proportion, about a tablespoon per cup, is this course's division of his recipe (lesson 10).
7. America's Test Kitchen, "Getting to Know: Thickeners" and "Can Potato Starch be Substituted for Cornstarch to Thicken Sauces?" . Read level: full, direct. Supports: the cold slurry, and a couple of minutes to reach full thickness.
8. America's Test Kitchen, "Technique #20: Make Superior Stir-Fries Without a Wok", 12 October 2023 . Read level: full, direct. Supports: a skillet's limits and cooking the protein in batches. That 300 g of prawns is the "large amount" it means is this course's reading, as the body says.
9. foodsafety.gov, "Cook to a Safe Minimum Internal Temperature", read through the Internet Archive's September 2026 capture . Read level: full. Supports: shellfish cooked until "pearly or white, and opaque".
10. FSA, "Cooking your food", GOV.UK, https://www.gov.uk/government/publications/cooking-your-food/cooking-your-food . Read level: full, direct. Supports: prawns, 48 hours, reheat once, and the recipe sentence and top tip, whose reading is this course's.
11. FSA, "How to chill, freeze and defrost food safely", GOV.UK, https://www.gov.uk/government/publications/how-to-chill-freeze-and-defrost-food-safely/how-to-chill-freeze-and-defrost-food-safely . Read level: full, direct. Supports: the pause button; freezing leftovers soon, cooled, in portions; labelling; freezer burn and meats as quality; -18°C; 24 hours after defrosting; partial defrosting; the microwave route; freezing again once cooked. It says nothing on refreezing thawed raw food or reheating from frozen.
12. USDA FSIS, "Freezing and Food Safety", last updated 9 August 2024, read through the Internet Archive's 23 September 2026 capture . Read level: full, direct. Supports: safe at 0°F; thawed food as perishable; storage times for quality; freezing flat and fast; foods that freeze badly and why; refreezing; reheating from frozen; freezing leftovers within 3 to 4 days.
13. USDA FSIS, "Leftovers and Food Safety", last updated 31 July 2020, read through the Internet Archive . Read level: full. Supports: 3 to 4 days, 3 to 4 months frozen, 165°F and a rolling boil, 3 to 4 days after thawing, and cooking cold-water thawed leftovers before refreezing.
14. CDC, "Prevent Botulism: Home-Canned Foods", 25 April 2024, read through the Internet Archive's September 2026 capture . Read level: full, direct. Supports: recipes that follow the USDA guide, no other recipes, and the toxin that cannot be seen, smelled or tasted.
15. National Center for Home Food Preservation, "Freezing Garlic-In-Oil" . Read level: full. Supports: the fridge and 4 days, or freezing.
16. Carla Luisa Schwan, "How to Safely Make Infused Oils", University of Georgia Cooperative Extension Circular 1334, 2024 . Read level: full, direct. Supports: the warning against substituting vinegar or lemon juice.
17. FSA, "Home food fact checker", GOV.UK, updated 21 August 2026 . Read level: full, direct. Supports: the rice rules, freezing within an hour, and reheating until steaming hot.
18. FSA, "Food allergy and intolerance advice for consumers", GOV.UK, updated 7 August 2026 . Read level: full, direct. Supports: the quoted lines. The batch-plan steps are this course's application, as the body says.
19. USDA FSIS, "Refrigeration and Food Safety", last updated 23 March 2015, read through the Internet Archive . Read level: full, direct. Supports: pathogens not changing taste, smell or appearance.
20. America's Test Kitchen, "Nailing the Perfect Ratio of Water to Rice" . Read level: full, direct. Supports: "set-in-stone ratios fail the home cook" and the factors behind evaporation.
21. Martin Philip, "What is baker's math, and how can I use it in my everyday bread baking?", King Arthur Baking blog, 28 April 2022 . Read level: full text, direct; the formula tables are images and were not read. Supports: no firm rules for the percentages, and salt as the exception.
22. USDA FSIS, "The Big Thaw: Safe Defrosting Methods", last updated 15 June 2013, read through a 2026 Internet Archive capture . Read level: full. Supports: a full day in the fridge for a pound of minced meat or boneless chicken breasts. Applying it to a portion of braise is this course's step, as the body says.