Basic ratio: 1 tablespoon vinegar or lemon juice + 1 cup milk of choice = 1 cup buttermilk
To make buttermilk, simply measure the vinegar or lemon juice into a liquid measuring cup. Fill the cup with milk up to the 1-cup line (so yes, you’ll be using just a tiny bit less than 1 full cup milk). Stir to combine, and let the mixture rest for at least 5 to 10 minutes before using.
The final texture should appear somewhat separated at the top, with some light curdling. Even if you don’t see a significant change in appearance, the acidity is present and your buttermilk should work as designed.
Following this ratio, you can make exactly as much buttermilk as you need. Keep in mind that one tablespoon is the equivalent of three teaspoons. Here are some alternate yields for your convenience:
- 1/4 cup buttermilk: 3/4 teaspoon vinegar or lemon juice + 1/4 cup milk of choice
- 1/3 cup buttermilk: 1 teaspoon vinegar or lemon juice + 1/3 cup milk of choice
- 1/2 cup buttermilk: 1 1/2 teaspoons vinegar or lemon juice + 1/2 cup milk of choice
- 2/3 cup buttermilk: 2 teaspoons vinegar or lemon juice + 2/3 cup milk of choice
- 3/4 cup buttermilk: scant 2 1/2 teaspoons vinegar or lemon juice + 3/4 cup milk of choice