Garum
Processintermediatedraft

Foams and whipping in air

Also searched as: whisked egg whites, whipping cream, whipping, meringue, foam

In short: When whisked, proteins unfold and form a skin around air bubbles. That creates a stable foam.

Picture it

Like soap bubbles whose skin is made of protein instead of soap.

Level 2 · Egg white turns to foam≈ 1 mm

Simplified model

What happens

The whisk beats air into the and stretches the protein molecules. They settle around the air bubbles and link into a skin. Fat disrupts this skin, which is why no yolk must get in. A little acid and gradually added sugar make the foam more stable.

Why it matters

, sponge, mousse and soufflé get their air from this foam, without any baking powder.

Where you meet it
MeringueEgg whiteMaking butterShake your own butterEgg whites with and without fatEgg (whole)Fat in generalCream

Rules of thumb

  1. Clean, grease-free bowl, no yolk.
  2. A pinch of acid or cream of tartar stabilises.
  3. Sprinkle in sugar only once soft peaks form.
  4. Egg whites at room temperature whip up better.

Levers

3
Mechanical work (kneading, whisking, stirring)whisk longer → stiffer, too long → grainy
Amount of fateven traces prevent foam
Amount of sugarstabilises, but add later

In practice

3

Eggs

Egg whites for sponge and soufflé: stiff but still glossy.

Milk and cheese

Cream forms a foam through its fat: whip it well chilled, otherwise it turns to butter.

Cakes and baking

A sponge rises only through the whipped-in air, so fold gently.

Related entries
Whipping (egg whites, cream)FoldingEgg whites won't whip stiffCream turns to butter
Sources · 2