On Food and Cooking

buttermilk,” made from ordinary skim milk
and fermented until acid and thick.
What’s the difference? True buttermilk is
less acid, subtler and more complex in flavor,
and more prone to off-flavors and spoilage. Its
remnants of fat globule membranes are rich in
emulsifiers like lecithin, and make it
especially valuable for preparing smooth,
fine-textured foods of all kinds, from ice
cream to baked goods. (Its excellence for
emulsifying led to the Pennsylvania Dutch
using it as a base for red barn paint!) Cultured
buttermilk is useful too; it imparts a rich,
tangy flavor and tenderness to griddle cakes
and many baked goods.
U.S. “cultured buttermilk” is made by
giving skim or low-fat milk the standard
yogurt heat treatment to produce a finer
protein gel, then cooling it and fermenting it
with cream cultures until it gels. The gelled
milk is cooled to stop the fermentation and
gently agitated to break the curd into a thick