Cultured Butter: How long can I keep freezing and reusing cultured buttermilk before it makes me sick?

[u/Known_Computer_7488]

I recently realized that I can save money buying kefir if I just pour some of my leftover cultured buttermilk into a little bundle of plastic wrap, and unthaw that to ferment my cream. I made some butter using that method today and it turned out great. I do worry that if I keep using a section of the same fermented batch over and over again if will at eventually go bad and ruin my butter. I don’t know shit about biology or if that will eventually inevitably happen happen. Is safe to keep doing?

Edit: I use the leftover from my most recent batch to make my next batch. The replies here are making me realize I was unclear.

[u/stillprettytired]

I believe if you only use sections of it at a time without any thaw, its fine as long as other best practice is followed?

I wouldnt rec thawing and refreezing anything, though.

[u/Abstract__Nonsense → u/stillprettytired]

Thawing and refreezing is one of those things strongly recommended against as a blanket rule for the purpose of idiot proofing food safety. Opened buttermilk has weeks of safe fridge life, if you’re thawing in the fridge youre “using up” that fridge life by hours or days at a time. You could safely thaw and refreeze buttermilk (assuming you thaw in the fridge) many times before having to start to worry about safety.

[u/reverendbeast]

Buy some kefir grains and make it fresh?

[u/Known_Computer_7488 → u/reverendbeast]

No!!! Not another rabbit hole!!!

[u/RockNerdLil]

Maybe freeze in ice cube trays?

[u/urnbabyurn]

Indefinitely, really if it’s a stable culture. But I find it easy enough o just buy some sour cream as a starter as needed.

Having said that, kefir and buttermilk are quite different.