When bread recipes call for dry milk powder, my preference is King Arthur’s Baker’s Special Dry Milk. Compared with the results of using other brands of “instant” dry milk, its results are a smoother, more mellow flavor, a more tender texture, and a significantly higher rise.
Unlike instant dry milk, which is intended to be reconstituted and processed at low heat, the Baker’s Special Dry Milk is heated to a high enough temperature during production to deactivate the enzyme protease, which impairs yeast production. (This dry milk will not reconstitute in liquid so it must be added to the flour.) The high heat process also produces an exceptionally fine powder, which disperses uniformly through the dry ingredients. Because the particles are so much finer than the more crystalline ones of instant dry milk, they pack down when being measured in a cup or spoon, so if replacing Baker’s Special Dry Milk with instant dry milk, by volume you will need double the amount to arrive at the same weight.