Fold

To fold means to combine two mixtures gently so the air in one of them stays in. You use it to add whipped egg whites, whipped cream or flour to a batter for mousse, sponge cake or soufflé. In bread making, folding means stretching the dough and folding it over itself to build strength during bulk fermentation.

How to do it

For a batter:

1. Stir a quarter of the light mix, such as egg whites, into the heavy mix to loosen it.
2. Add the rest of the light mix on top.
3. Using a large rubber spatula or metal spoon, cut down through the middle to the bottom of the bowl.
4. Sweep the spatula along the bottom and up the side, then turn it over on top.
5. Turn the bowl a quarter turn and repeat.
6. Stop as soon as no white streaks are left.

For bread dough:

1. With wet hands, grab one side of the dough and stretch it up until you feel it resist.
2. Fold it over to the other side.
3. Turn the bowl and repeat on all four sides. That is one set.
4. Repeat every 30 minutes for 3 to 4 sets.

How to tell it is done

A folded batter is even in color with no streaks and still looks light and puffy. A folded dough feels tighter and smoother after each set and holds its shape better in the bowl.

Common mistakes

• Stirring in circles or whisking. That knocks out the air, and the cake or mousse turns flat and dense.
• Folding for too long. A few faint streaks are better than a deflated batter.
• Adding the whites all at once to a stiff base. Lighten it first with a small amount.
• Tearing bread dough. Stretch only until you feel resistance.

In recipes

"Fold in the egg whites" or "fold in the flour" always mean the gentle method. "Fold in the blueberries" just means stir them in gently so they do not break. "Stretch and fold" or "coil fold" refers to the dough method. A recipe that says "just combined" after folding means stop early.