⭐ Milk + Lemon Juice or Vinegar (Best Nut-Free Option)
1 cup milk + 1 tablespoon lemon juice or white vinegar (let sit 5-10 minutes)This substitute works because the acid (lemon juice or vinegar) lowers the pH of the milk, simulating the lactic acid content of buttermilk. The acidity helps to tenderize the gluten network and enhances the activity of the sourdough starter, promoting proper fermentation and rise.
For best results, use whole or 2% milk and allow the acid to curdle the milk slightly before adding to the dough. Avoid using skim milk as it reduces fat content, which can affect crumb softness.
Compared to buttermilk, this substitute produces a very similar crumb texture and flavor profile, preserving the characteristic tang and moistness of sourdough bread.