I always understood that buttermilk refers to the milk left over from making butter. However, these days I see buttermilk culture. Are they both called buttermilk? Or do you sometimes culture the cream with the buttermilk culture before making butter?
Just as background, I'm use to making butter with the pure agitation (churning) method, and have recently started making butter with Fil Mjolk starter culture (you culture the cream like yoghurt, then churn the butter). However, the buttermilk culture is something completely different than these two methods.
If it's not for making butter, what's the buttermilk culture for?