Whisking

The three jobs

Aerating

Egg whites, cream, whole eggs for a genoise. You are beating air bubbles in and building a structure that holds them. Over-doing it destroys the structure.

Emulsifying

Mayonnaise, hollandaise, vinaigrette. You are shearing fat into droplets small enough to stay suspended in water. Here, more whisking is generally better.

Mixing

Batters, sauces, dressings. You are combining. Whisk enough to be smooth and no more — over-mixing a flour batter develops gluten and makes it tough.

How a foam is built, and how it breaks

When you whisk egg white, the whisk stretches and unfolds the proteins. They spread out around the air bubbles you are introducing and link to each other, forming a flexible film that holds the bubbles in place. That is a foam.

Keep whisking past the right point and those proteins keep linking. The film gets tighter and less flexible, the bubbles cannot expand, water is squeezed out, and the foam breaks into a grainy, watery, lumpy mess. This is over-whipping, and it is not reversible for egg white.

Cream does the same thing by a different route: fat droplets stabilise the bubbles, and whisked too far they join up into butter. Over-whipped cream can be partly rescued by folding in a little fresh liquid cream; over-whipped egg white cannot.

The peak stages

Lift the whisk out and look at what the mixture does. This is the only reliable measure.

Frothy

Large loose bubbles, still liquid. Not yet doing anything useful.

Soft peak

A peak forms and immediately flops over. The right stage for folding into a batter or a mousse.

Firm peak

A peak holds and the tip curls. The everyday target for whipped cream and most meringue.

Stiff peak

A peak stands straight up. For meringue that has to hold a shape. Very close to over-whipped.

Over-whipped

Grainy, dull, watery at the bottom, or curdled. For cream, add liquid cream and whisk by hand. For egg white, start again.

The practicalities

• No fat in egg whites. A speck of yolk or a greasy bowl prevents the foam. Metal or glass bowls, not plastic.
• Cold cream, cold bowl, cold beaters. Cream whips faster and more stably cold; warm cream may not whip at all.
• Room-temperature egg whites whip to a greater volume than cold ones.
• A pinch of acid stabilises egg whites — cream of tartar, lemon juice, a copper bowl. It slows the protein bonding so there is more margin before over-whipping.
• Add sugar gradually and after soft peaks for meringue. Too early and it inhibits the foam forming.
• Use a balloon whisk for volume and a flat whisk for a roux. The shape matters: more wires and a rounder shape mean more air.
• Fold, do not whisk, once the foam is made. A folded mixture keeps the air; a whisked one knocks it out.

Common questions