If you're on Pinterest, you might have seen the pin going around for freezing buttermilk so that it doesn't go bad before you have a chance to use it, and then you always have it on hand when you need it. Well, I just tried going to the link in that pin to find out more, and Pinterest told me it was blocked as spam!! So, if you've also got that pinned, well, it's not going to work. BUT, just Google "freezing buttermilk", and you'll get tons of hits. Here's the one I went with from theKitchn.
The thing about buttermilk is I can never find it in any size less than a quart. But I don't need a whole quart. So I decided to freeze my leftover buttermilk. It was super easy to do.
I poured one tablespoon of buttermilk into the slots in an ice cube tray. I filled four ice cube trays!! That's a lot of buttermilk!
Once it's frozen in the trays, just pop those suckers out and place them in a freezer bag. It might be helpful to label the freezer bags so a) you can remember how much buttermilk each cube is and b) you can remember what the heck those white things are in your freezer.
The tip from theKitchn is that after you defrost your buttermilk cubes, you'll have to whisk it a bit because the whey and the solids will have separated. Maybe I'll write that on my freezer bags, too.