1-Measure: 15 milliliters of a food-grade acid, such as distilled white vinegar or lemon juice, into a clean bowl or measuring cup.

2-Add: 200-250 milliliters of milk to the acid, stirring gently to combine the liquids fully.

3-Let: the mixture sit at room temperature for approximately 10 minutes, allowing it to curdle and thicken as the acid reacts with the milk proteins.

4-Once curdled: stir the mixture again to achieve a uniform texture before using it in recipes.

5-For traditional buttermilk, pour fresh raw milk into a container and let it stand at room temperature, where ambient bacteria cause fermentation and cream separation over variable time.