I've never used buttermilk for baking before (it's not very common in the UK, although I believe it was in the past), but I found this great recipe for chocolate brownie cake for my brother's 15th birthday (pics here)- and it had buttermilk it (it also had sour cream, which is like buttermilk made from cream which I substituted with 3/4 buttermilk and 1/4 butter), previously I have just used milk with a little lemon juice left for 15 mins 'til it sours, but I thought that as it was such a crucial part of the cake. It's not too hard to find in where I live - I just picked some up in Tescos.
I had a little bit of buttermilk left over and when looking up what to do with it, I found out that modern 'buttermilk' is not really buttermilk at all (as in the slightly sour milk left over from churning butter), but it is a cultured product similar to yogurt. Even better was that you can 'make' your own buttermilk using a bit of bought buttermilk as a starter, I just put the leftover buttermilk in a container, topped it up with milk and left it in a cupboard for about 15 hours, until it thickened and smelled a bit like yogurt. Not sure why it doesn't go bad, like milk usually would being left on the side, but it didn't!
My buttermilk didn't come out as thick as the store-bought kind that I used as a starter, but that may be because they used something else to help thicken it, next time I'll add a little powdered milk, as I have read online that people use this to make homemade yogurt thicker. I am a bit confused tho' as PrayzGod says on her blog that homemade buttermilk generally comes out thicker than the stuff from the store, so I don't know where I went wrong! The white 'blobs' on the side of the container and left on the spoon are where the lactic acid in the milk has caused it to clabber, which is what makes it into buttermilk.
Of course once I'd made it I wanted to make something with it - I made some super yummy buttermilk oat scones and added dried cranberries and sultanas to the mixture - so yummy. I'd recommend making scones with buttermilk, it really does make them lighter.
