Buttermilk (Best Option)
1 cup buttermilk per 1 cup whole milkButtermilk contains lactic acid which reacts with leavening agents like baking soda to produce carbon dioxide, helping biscuits rise and become fluffy. The fat content in buttermilk also contributes to a tender crumb.
When substituting, reduce or eliminate baking powder if the recipe calls for it, since buttermilk's acidity activates baking soda. Watch for slight flavor changes due to buttermilk's tang.
Compared to whole milk, buttermilk produces biscuits with a more pronounced rise, flakier texture, and a subtle tang that enhances flavor complexity without compromising moisture.