Milk + Lemon Juice (Best Option)
1 cup milk + 1 tablespoon lemon juice (let sit 5-10 minutes)Milk combined with lemon juice creates an acidic environment similar to buttermilk by curdling the milk slightly, which helps in gluten development and activates baking soda or yeast properly in bagel dough. The acidity also contributes to the characteristic tangy flavor of bagels.
For best results, use whole milk for adequate fat content and allow the mixture to sit for 5-10 minutes to curdle before incorporating into the dough. Avoid using skim milk as it reduces fat and affects texture.
Compared to buttermilk, this substitute produces bagels with very similar chewiness and crust, maintaining the traditional flavor profile with minimal difference.