Milk + Lemon Juice (Best Option)
1 cup milk + 1 tablespoon lemon juice (let sit 5 minutes)This substitute works by acidifying the milk, which slightly curdles it and mimics the lactic acid content of buttermilk. The acidity helps break down muscle proteins in the meat, tenderizing the burger and enhancing moisture retention.
For best results, use whole milk for fat content similar to buttermilk. Let the mixture sit for 5 minutes to allow curdling before mixing into the burger blend. Avoid using skim milk as it reduces fat and moisture.
Compared to original buttermilk, this substitute maintains the balance of acidity and moisture, resulting in similarly tender and juicy burgers with minimal flavor deviation.