Why Does Whole-Wheat Flour Behave Differently in Dough?

Bran is the outer covering of the wheat kernel. When milled, it leaves small, hard particles with sharp edges. As dough is kneaded, gluten forms a network of long strands; these particles get between the strands and cut and break them. The result is a noticeably weaker structure than with white flour that has the same protein content. When stretched, the dough tears sooner, gas produced during fermentation escapes, and the bread turns out flatter and denser. For the same reason, whole-wheat bread feels heavier and denser than white bread; this is not a flaw but a characteristic of that flour.

The second difference is water. Bran and germ contain fibers that are not present in white flour, and these fibers absorb water; the absorption takes time rather than happening immediately. That is why whole-wheat dough may look right while being kneaded but become firmer half an hour later. There are two solutions: make the dough a little wetter, and let the flour and water rest together before kneading. The rest gives the bran time to absorb water.

Whole-wheat dough ferments faster because bran and germ contain plenty of nutrients for the yeast to use. This may seem like an advantage, but it requires attention: whole-wheat dough can reach the point that the same recipe reaches in three hours with white flour sooner, and if you miss it, the dough can pass its peak. So watch the dough rather than the clock; the finger-poke test is especially useful here, and reassess the timing with each batch. Oven spring is also lower, so the dough should be placed a little higher in the pan.

There are several ways to improve the result. The most common is blending: use some whole-wheat flour and the rest white bread flour, and a half-and-half blend gives the flavor while preserving loaf volume. Second, fold the dough at intervals instead of kneading it; this puts much less strain on the weak network. Third, choose finely milled whole-wheat flour, since smaller particles have less cutting effect. Fourth, add a small amount of powdered milk or honey; both improve softness and partly balance the bran’s toughness.

Whole-wheat flour spoils much faster than white flour because of the oil in the germ. As that oil comes into contact with air, it turns rancid and gives the flour a sharp odor. Buy whole-wheat flour in small amounts and store it in a sealed container in a cool place; if keeping it for a long time, use the refrigerator or freezer. Smell it before using: flour with a rancid odor will spoil the dough from the start and should not be used.