Buttermilk substitute in baking?

My favourite chocolate mudcake recipe calls for buttermilk. Not a lot - just enough to make me buy a huge carton (because that is the only way it comes here), use 1/5 of it and then let it sit in the fridge until it has little buttermilk babies of its own!

I am so over wasting and am just not game to use old buttermilk in what I regard as a relatively expensive cake to make (and potentially ruin!).

I am really not convinced about using milk with a bit of lemon or vinegar added (though I stand advised if you ladies have had success with it).

I am wondering if I could just use Greek yoghurt or sour cream? I imagine these would be a closer substitute? Again, what do you all think?

Do you think I could freeze the buttermilk into portions? Can you freeze buttermilk?

TIA

not sure about using other things, id just use the vinegar recipe, ive done that before without any issues

You can freeze buttermilk. I have some frozen, but am yet to see if it works the same when defrosted.

I know Christy uses a combination of ricemilk and tofu blended together....probably not what you're after but there are alternatives.
And yes milk freezes well just takes ages to thaw.

You can also make your own buttermilk with milk and vinegar or lemon juice. But like Astrid says I freeze my buttermilk in ziplock bags in 125ml lots.

Perfect excuse for buttermilk pancakes on the weekend! :D

I have used milk and vinegar in the past - works fine.

As already stated, buttermilk makes amazing pancakes/pikelets - whick also freeze well.

I've never frozen buttermilk, so can't help you on that one.
I've used low fat sour cream or plain yohurt as a substitute before with excellent results.
You can also get powdered buttermilk, I think. I've never tried it myself, but my MIL uses it. That would prevent waste - you could just reconstitute the amount you need, and the rest would keep without issues. But, like I said, I haven't tried it myself. :)
All the best!

I usually do some kind of sour cream & milk mix. Never tried the vinegar option... sounds a bit too chem-class for my liking! ;)

Thank you for all of your suggestions. I am making a mudcake this week and plan to use the milk / vinegar combo. Failing that I will try the frozen buttermilk option.

I like to think that I am fairly "well-versed" in the kitchen, but the buttermilk pancakes that I made a couple of months back made me feel like I should be banned from all things cooking! They were TERRIBLE - like little rubber door stops! So yeah - until I work out how to make good ones, pancakes aren't really an option :D

I read the title as "Breastmilk Substitute in baking" and was going to suggest using cows milk:lol:

Ahem, sorry not much help am I? As you were...

to get the best light & fluffy pancakes, separate the eggs, mix the yolks in as per normal, but with the white - whip them until soft peaks form, then fold them into the batter at the end. OMG... so simple, and the result is amazing! Hasn't failed me yet!