Low-Fat versus Nonfat Buttermilk

By Cook's Illustrated Published September 2015

Are low-fat and nonfat buttermilk interchangeable in recipes?

Readers have asked us if low- and nonfat buttermilk are interchangeable in baking recipes. To find out, we made pancakes with both types and found that they produced comparable results in both appearance and texture. Our Flaky Buttermilk Biscuits (see related content) revealed a little more variation—those made with nonfat buttermilk were slightly denser and not as flaky—but both options produced acceptable biscuits. Buttermilk pie, though, was another matter: The filling made with nonfat buttermilk was grainy and slightly curdled. That’s because low-fat buttermilk has an asset that nonfat buttermilk lacks: fat, which helps prevent eggs in a custard from curdling. Fat coats the proteins, making them less likely to clump. So you can use non- and low-fat buttermilk interchangeably in most recipes. However, if you’re making a custard-style dessert (like pie or panna cotta), stick with the low-fat type.

OK FOR BISCUITS AND PANCAKES: Nonfat buttermilk works just fine.

NOT OK FOR CUSTARD PIE: Filling made with nonfat buttermilk turns grainy and curdled.