The first step to make cultured buttermilk will be to order an heirloom buttermilk culture and follow the directions for getting this started. After this is going you can simply pour almost a quart of cold or fresh raw milk into a clean quart jar, add a 1/4 cup of yogurt from the previous day's buttermilk, whisk it well, put a lid on it, and let it sit at room temperature on the counter for 12 to 24 hours depending upon what temperature of your house is at. You will know it's done when it becomes thick. When you are getting started with the culture, it might not be as thick the first day, but it will get thicker by the second culturing. In order to preserve the culture, this will need to be cultured at least once per week. Doing this daily keeps the buttermilk tasting fresh and not sour.
