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How heat sets protein

Also called denaturation; coagulation

Why an egg becomes solid, fish flakes, and meat goes from translucent to opaque.

60โ€“75 ยฐC (140โ€“167 ยฐF)

What it is

Proteins in raw food are folded into compact shapes. Heat shakes them loose; the unfolded chains bond to each other and to water, forming a solid network. That is setting, and it is not reversible.

Why it works

Different proteins set at different temperatures, which is the whole basis of doneness. Egg white begins around 62 ยฐC and yolk around 65 ยฐC, which is why a barely-set yolk and a firm white can coexist. Squeeze the network too hard with more heat and it expels the water it was holding โ€” a dry chicken breast and a weeping custard are the same failure.

When to use it

Eggs, custards, fish, meat, cheese-making, tofu.

What goes wrong

Thinking of doneness as time rather than temperature; cooking custards over direct heat; assuming more heat makes a protein firmer rather than drier.

Meridian cooking encyclopedia โ€” Watchman Productions

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