Eggs: Coagulation Temperatures and What They Decide

Two numbers

• Egg white begins to set at about 62°C.
• Yolk begins to set at about 68°C.
• Above 80°C the proteins contract hard and squeeze water out — dry curds sitting in liquid.

Nearly every egg failure follows from those three lines. Eggs go wrong from too much heat far more often than from too little.

Scrambled eggs and omelettes want low heat

Put an Omelette over high heat and the outside browns and tightens while the inside goes dry. Tenderness only comes from low heat, slowly, kept moving.

• Medium-low pan: butter should sizzle without colouring.
• Take it off while it still looks slightly underdone. Residual heat keeps cooking it.
• A splash of milk or cream raises the setting temperature and widens your margin.

Gyeranmari applies the same principle in layers — each layer has to be rolled before it fully sets, or the layers will not bond.

Boiled egg timings

Starting in cold water makes timing unrepeatable. Lower them into boiling water and time from there (fridge-cold, medium eggs):

• 6 min — white barely set, yolk still liquid.
• 7 min — jammy, set only at the yolk's edge.
• 9 min — just moist in the middle.
• 11 min — fully set, not yet chalky.
• 13 min+ — crumbly yolk with a grey-green ring (iron sulfide). Overcooked.

Into cold water immediately: it stops the carryover cooking and helps them peel.

Getting them to peel

Very fresh eggs peel badly — the internal pH is low and the white clings to the membrane. Eggs a few days old peel better. Beyond that, starting in boiling water and chilling hard afterwards does the most.

Steamed custards: ratio and a sieve

For Gyeranjjim, egg to liquid is about 1 : 1.5. Less and it is rubbery; more and it will not set.

Two things make the texture:

• Pass it through a sieve to catch the chalazae and any lumps — that is what makes it smooth.
• Low heat, lid on. Steamed hard it pits and weeps. Once the steam is up, drop the heat.

Yolk-thickened creams like Chocolate Mousse follow the same rule — past 70°C they curdle, which is why they are made over a water bath. See also Why sauces split.

Keep fat away from whipped whites

A trace of yolk in the whites and they will not whip: the fat destabilises the protein film.

• The bowl and whisk must be grease-free.
• Room-temperature whites whip higher.
• Acid — a few drops of lemon or vinegar — stabilises the foam.
• Add the sugar gradually rather than all at once.

Dishes where the egg is the dish

Tamago Sando lives or dies on the texture of a hard-boiled egg, so the timing is the recipe; French Toast is a custard absorbed into bread, so the bread needs time to take it up.