Q. I remember my grandfather drinking a big glass of cold buttermilk, but it wasn't the same as the stuff we get now. Where can I find old-fashioned buttermilk?
Unfortunately, the short answer is that you can't. Traditional buttermilk, the soured liquid remnants of cream that was used to make butter, can't be made from pasteurized cream. The high-temperature process destroys the natural lactobacillus bacteria.
N.C. law prohibits the sale of raw milk products to consumers. Raw milk, butter made from unpasteurized cream and young cheese from raw milk are all illegal.
The loophole that allows raw-milk co-ops to survive is that sale for animal feed is not prohibited. As long as the farm posts a sign stating its milk is for feed, it is free to distribute raw milk.
So while you can find raw milk in North Carolina, the sale of unpasteurized butter is illegal. So you're unlikely to find traditional buttermilk unless you know a dairy farmer.
Cultured buttermilk is made by introducing a culture of bacteria to pasteurized milk and allowing that culture to ferment. Cultured buttermilk is more acidic than traditional buttermilk; this acidity denatures a portion of the milk's proteins and gives the milk a thick, clabbered appearance.
Cultured buttermilk can be made from milk pasteurized at a lower temperature. This buttermilk is more difficult to find, but has a more pleasing taste. Tom Trantham's Happy Cow Creamery, in Pelzer, S.C., sells buttermilk made from milk pasteurized at low temperature.