Cultured buttermilk (from scratch) :
1 cup filtered fresh raw milk
5+ cups milk
Allow a cup of filtered fresh raw milk to sit covered at room temperature until it has clabbered (usually several days).
Place 1/4 cup of the clabbered milk in a pint mason jar, add a cup of fresh milk (does not have to be raw at this point), cover, shake to mix, allow to sit at room temperature until clabbered.
Repeat this transfer of sub-culturing several more times until the milk dependably clabbers in 24 hours. Taste a small amount to confirm that it is tart, thickened, and has no off flavors. It should taste tart not bitter, for instance.
To then make a quart of buttermilk with this culture, add 6 ounces of the buttermilk to a quart jar, fill with fresh milk, cover, shake to mix, allow to sit at room temperature until clabbered.
Cultured buttermilk (from innoculation) :
1/4 cup cultured buttermilk
4 cups raw milk
Pour buttermilk into your clean jar. Top off the jar with your plain milk.
Tightly screw lid to the jar and shake vigorously for 1 minute.
Place in a warm (but not hot) area out of direct sunlight. Let it sit there for 12 to 24 hours, until thickened. Refrigerate when thick.
Use within two weeks.
Buttermilk Substitutes :
cream of tartar
Measure 1 3/4 tablespoon cream of tartar plus 1 cup milk. Whisk to combine and let stand at room temperature for 5-10 minutes, until curdled and then stir.
Add one tablespoon of lemon juice to a liquid measuring cup. Then, add milk until the amount reaches one cup. Let the mixture stand at room temperature for 5-10 minutes. The milk should look curdled. Stir and you have homemade buttermilk!
You can easily make a buttermilk substitute with 2 tablespoons milk plus enough plain yogurt to equal one cup. Stir to combine and then use your as recipe instructs.
If you have sour cream on hand you can easily make a buttermilk substitute by thinning the sour cream with a bit of milk until it reaches the consistency of buttermilk. Stir to combine and then use your as recipe instructs.
Add one tablespoon of white vinegar to a liquid measuring cup. Then, add milk until the amount reaches one cup. Let the mixture stand at room temperature for 5-10 minutes. It should look curdled. Stir and you have homemade buttermilk!