I have made my own yogurt and creme fraiche with no difficulties. But with buttermilk I've had problems. I do it the way I'm instructed to: add some live cultured buttermilk to a quart of milk, let it sit in a warm place, and voila - buttermilk.
The product is definitely clabbered. It's thick and tastes as good as the milk I make it with. But the consistency is dreadful - in my opinion. How to describe? It is thick and doesn't pour well. It comes out of the container in a glob. If I put a clean finger in it, I can literally pull up a rope of goo. The mouth feel is slimey. (No other word to describe it.) The original buttermilk from which this is made is not slimey or ropey or gooey - it's thin and curdled.
Does anyone have any idea what is going on, here? Should I disregard the instructions and go ahead and heat the milk, thus denaturing the proteins, as one does in yogurt-making? Or should I spring for a non-homogenized brand of milk? I am using the usual supermarket pasteurized, homogenized milk. Whole milk, not low-fat (the buttermilk is low fat, but that should have nothing to do with this. I think.)