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IN THE three years since I started this column, I have somehow avoided writing about eggs, even though I cook them for breakfast most weekends. What is there to learn about such a simple food?

Quite a lot, it turns out. An egg may look the same from day to day, but it is undergoing subtle changes even before you crack it open. Water vapour and carbon dioxide escape through tiny pores in the shell, raising the pH of the egg white. Air diffuses into the shell, expanding the tiny air sac inside. For this reason, a fresh egg sinks in water, but an oldish one will stand on end at the bottom of a water-filled container and an even older one will float to the surface.

As the egg white becomes more alkaline, it gets less viscous because of weakening interactions between some of the proteins in it. If you try to fry or poach an old egg, the white spreads apart instead of holding together neatly.

In a raw egg, the protein chains are tightly folded up. When heated, these chains unravel, or denature, and this allows them to bond to neighbouring proteins, creating a gel that traps water.

Various egg proteins denature and coagulate at different temperatures, but, in general, the white becomes solid at around 65°C (150°F) and the yolk at 70°C (158°F). In professional kitchens, “boiled” eggs are often not boiled, but to produce reliably runny yolks.

When it comes to scrambled eggs, the ideal for me is a super-soft and moist consistency. If they are overcooked, the proteins bind together too tightly and squeeze out water, making the texture firm and dry.

That means gentle heat and constant stirring are the way to go. It is important to turn off the heat just before the eggs reach the desired consistency, as residual heat in the pan will keep them cooking a little longer.

Others prefer light and fluffy scrambled eggs: this requires relatively high heat so that pockets of steam form within the eggs as they coagulate.

In either case, salting the eggs before cooking helps achieve a more tender result. Most egg proteins have a negative electrical charge, so they repel each other to some degree. Salt supplies positive sodium ions, which gather around the negatively charged regions and help them approach each other while mostly folded up. The result is that they can’t intertwine and bind so tightly when heated.

Acids have a similar effect: they cause proteins to denature at a lower temperature, but also help them coagulate before they have fully unwound. For extra-soft scrambled eggs, try adding a teaspoon of lemon juice or vinegar to two eggs before cooking. It might sound odd, flavour-wise, but I find that the slight acidity actually works well with the richness of the egg, just as it does in hollandaise sauce.

Sam Wong is assistant news editor and the self-appointed chief gourmand at 91av. Follow him @samwong1

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