Its a substitute for buttermilk.

you might [use it] in pancake or biscuit batter.

And you cant taste the sour!

Ive pushed it, and let the milk get really old.

Its amazing how you wont taste even the slightest bit of bitterness.

Gunders notes, however, that there is still a limit.

If its a clotted, bitter liquid thats really starting to separate, just toss it out.

For a sour milk pancake recipe and more tips on avoiding food waste, check out the link below.

Dont Toss That Sour Milk!

And Other Tips to Cut Kitchen Food Waste| NPR

Photo bySarah C.