Buttermilk (Best Option)
1 cup buttermilk per 1 cup whole milkButtermilk works well because its acidity reacts with baking soda or baking powder in the waffle batter, producing carbon dioxide that helps waffles rise and become fluffy. The fat content is similar to whole milk, contributing to moisture and richness.
To use buttermilk successfully, ensure your recipe includes a leavening agent that reacts with acid, such as baking soda. If not, you may need to adjust leavening amounts. The batter may be slightly thicker, so adjust liquid if needed.
Compared to whole milk, buttermilk waffles have a more tender texture and a subtle tangy flavor, which many find desirable. Browning is enhanced due to the acid-base reaction promoting Maillard browning.