Diastatic malt powder is the “secret ingredient” savvy bread bakers use to promote a strong rise, great texture, and lovely brown crust. Especially useful when flour does not have barley malt added, as is true for most whole wheat flour and many organic flours.
Active enzymes in diastatic malt help yeast grow fully and efficiently throughout the fermentation period, yielding a good, strong rise and great oven spring. Add only a small amount of 1 teaspoon per 3 cups of flour, or around 1% in Baker’s Math of non-malted flour.
Many commercial all-purpose or high-protein bread flours contain added barley malt (or “malted barley flour,” or “enzymes,” all of which are the same base ingredient), omitting the need for diastatic malt as an isolated ingredient in baking. However, many organic, whole-wheat, and home-milled flours do not contain additives, meaning doughs made as such can benefit from added malt.
I may use malted flour, and if not, I add diastatic malt powder to plain flour in sourdough bread and soft pretzels!