Making your own Buttermilk [split from LA]
The February issue of "Bon Appetit" has a simple method of making your own buttermilk. It entails culturing whole milk with a bit of commercial buttermilk. I did it with Trader Joe's buttermilk and organic whole milk (I find their organic dairy products to be excellent quality - especially the heavy cream) and the results were delightful. This won't help the OP with old school buttermilk, the leavings from churning butter, but it makes great biscuits.