The Bread Ecosystem

• Bread's rise is a byproduct of the natural life cycle of yeasts. The tiny microorganisms digest naturally occurring sugars in the flour and other ingredients, turning out alcohol and carbon dioxide as by-products. The stretchy gluten proteins in your bread dough trap the carbon dioxide in tiny pockets throughout the dough, which become expand as the bread bakes in the oven's heat. Yeasts grow best in moderately warm temperatures, and in neutral or mildly acidic pH.

Yogurt vs. Milk

• Dairy products aren't necessary for making bread, but many recipes call for varying quantities of milk or butter. This makes the dough richer and softens its crumb, so the resulting bread is easier to chew. It also makes the bread more nutritious, and adds calcium, protein and various vitamins and minerals. Yogurt gives a similar result, and adds a faint and pleasant tang to the bread's flavor. Yogurt is more acidic than ordinary milk, so it can make changes in the dough's behavior.

Effects of Yogurt

• Small amounts of yogurt don't dramatically increase the dough's acidity, but if it is the main form of liquid in your dough, it can have an impact. Yeasts work more slowly in the acidic dough, so it will take longer to rise. The crust browns best with a more alkaline dough, so -- like sourdough -- bread baked with yogurt will be paler. It can also be denser, because acidity tends to weaken the strands of gluten that give your bread its light texture.

Adapting

• It is relatively easy to adjust your bread recipe to allow for the effects of yogurt in the dough. To compensate for weakening the gluten, you can switch to bread flour or simply add refined gluten to your dry ingredients. To compensate for the paler crust, brush your loaves with butter or milk. The dairy products will caramelize in the oven's heat, giving an attractive golden color. Alternatively, you could neutralize the yogurt's acidity by whisking in a small amount of baking soda before you add it to the dough. This minimizes the yogurt's acidity, but leaves its nutrition largely intact.