🍳 The Science of Cooking

What you’ll learn

1. Heat Is the Whole GameUnderstand conduction, convection and radiation, what the two numbers on a pan actually mean, and why water sets a ceiling on browning.Cooking is the controlled transfer of heat into food by three routes: conduction through contact, convection through a moving fluid, and radiation as infrared. Metals differ enormously at conducting it — copper runs at about 401 watts per meter-kelvin against cast iron's 52, so copper is roughly eight times faster, not the twenty times often quoted. Per unit of volume the two store almost the same heat, so a cast iron skillet's reservoir comes from its thickness and mass rather than from the metal. Water sets a hard ceiling near 100 degrees Celsius, which is why wet or crowded food steams instead of browning. Diagnosing which mode of heat is failing you is how you rescue a dish.
2. The Maillard ReactionExplain the Maillard reaction, the three levers that control it, how it differs from caramelization, and how to trigger it deliberately.The Maillard reaction, described by Louis-Camille Maillard in 1912, is a heat-driven cascade between amino acids and reducing sugars that produces browning and hundreds of savory aroma compounds. Three levers control it: temperature, surface dryness and pH. It becomes fast enough to matter above roughly 140 to 165 degrees Celsius — but food chemists are explicit that treating it as a high-temperature-only reaction is a misconception, since it also runs slowly at low temperatures, which is how dulce de leche browns at boiling point. It runs faster in slightly alkaline conditions. Caramelization is a separate process, the breakdown of sugar alone with no protein, starting near 160 degrees Celsius.
3. Proteins and the Magic of EggsUnderstand protein denaturation and coagulation, the temperatures at which an egg sets, what resting meat does and does not do, and how collagen becomes gelatin.Heat denatures proteins, unfolding them so they link into a solid. Egg white begins setting around 60 to 62 degrees Celsius and is tender by 65; the yolk thickens near 65 and sets by 70 — which is why five degrees separates a jammy yolk from a chalky one. Resting meat measurably reduces the juice lost on slicing, but the popular explanation, that the fibers reabsorb their juice, is hard to defend, because cooking's protein damage is not reversible; what certainly changes is that the temperature gradient evens out and the cooling juices run less freely. Carryover cooking keeps the center rising five to ten degrees after the heat is off. In tough cuts, long slow moist cooking converts collagen into gelatin.
4. Emulsions: Mixing the UnmixableExplain how emulsions suspend oil in water, what actually does the emulsifying in an egg yolk, and why emulsions break and can be rebuilt.An emulsion breaks one liquid into microscopic droplets suspended in another, held apart by an emulsifier that binds both oil and water. Egg yolk is what makes oil-heavy mayonnaise possible, and while lecithin usually gets the credit, reviews of the science put yolk's proteins and lipoproteins — livetins, phosvitin and low-density lipoprotein granules — ahead of the phospholipids as the dominant emulsifiers. That is why the oil goes in slowly at first. Emulsions break for nameable reasons: oil added too fast, heat that clumps the proteins, or cold that crystallizes the fat. A broken sauce is rebuilt by dribbling it into a small fresh base. Mustard, starch, gelatin and butter are other everyday helpers.
5. Bread: Gluten, Yeast, and SteamUnderstand gluten development, yeast fermentation, oven spring and steam, and how starch sets the crumb and later causes staling.Mixing flour and water forms gluten, an elastic protein network that traps gas. Yeast, a single-celled fungus, ferments sugars into carbon dioxide that inflates the dough while building acids and aroma over hours. In the oven, oven spring gives a final violent burst of rise, and injected steam keeps the surface flexible long enough to expand before it sets; a scored line controls where the loaf tears. The rise stops as the interior passes roughly 60 to 85 degrees Celsius and the starch gelatinizes and the gluten coagulates, locking the crumb; the center never passes about 98 degrees because water sets the ceiling. Starch later recrystallizes as staling, which is why refrigeration speeds staling up and gentle reheating partly reverses it.
6. Salt, Fat, Acid, HeatUse Samin Nosrat's salt, fat, acid, heat framework to diagnose and balance a dish, and understand what each element actually does.Salt, fat, acid and heat are the four levers behind balanced cooking, named in that order by the chef Samin Nosrat in her 2017 book Salt, Fat, Acid, Heat. Salt deepens flavor, measurably suppresses bitterness, and helps meat hold water. Fat carries aroma compounds that will not dissolve in water, builds texture, and allows the surface temperatures browning needs. Acid brightens and cuts richness, and denatures protein without heat as it does in ceviche. Heat drives every transformation in the course. When food tastes dull or heavy the fault is almost always one of the four, which turns the vague sense that a dish 'needs something' into four questions you can answer.
7. Why Recipes FailLearn the documented physical causes of common cooking failures, and how knowing them frees a cook from following recipes.Most cooking failures trace to a short list of documented causes: the wrong temperature, the wrong amount of moisture, a broken emulsion, or gluten over- or under-worked. Many disasters are the same protein failure in different costumes — milk curdling, custard seizing, scrambled eggs weeping, cheese sauce splitting into oily strings — all of them heat pushed past a setting point, and none of them fully reversible. Soggy crusts and pale roast vegetables are both water that could not escape fast enough. Baking is unforgiving because its chemistry locks in before you can taste and adjust. Understanding the science lets a cook diagnose a dish rather than follow instructions blindly.

Questions this course answers

Grounded in trusted sources

• Harold McGee, On Food and Cooking (Scribner, 2nd ed. 2004)
• El Hosry et al., Maillard Reaction: Mechanism, Influencing Parameters… Foods 14 (2025), doi:10.3390/foods14111881
• Abirached et al., Strategies for Reducing Fat in Mayonnaise, Foods 14 (2025), doi:10.3390/foods14173133
• Breslin & Beauchamp, Suppression of Bitterness by Sodium, Chemical Senses 20 (1995), doi:10.1093/chemse/20.6.609
• Institute of Food Science and Technology — Protein: coagulation
• The Engineering ToolBox — thermal conductivity, specific heat and density of metals
• Listrat et al., How Muscle Structure and Composition Influence Meat and Flesh Quality, TSWJ 2016, doi:10.1155/2016/3182746
• Samin Nosrat, Salt, Fat, Acid, Heat (Simon & Schuster, 2017)

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