This heirloom-variety buttermilk starter creates a traditional cultured buttermilk that is rich in nutrients. Homemade buttermilk can be used for baking, drinking or can be added to cream for makingcultured butterand is delicious in a variety ofrecipes. Eachbox contains 2 packets of starter culture. Activate1 packet using 1 quart pasteurized milk (store 2nd packet in the freezeras a back-up). Cultureson the countertop at 70-77F,no appliance required. Culturemay be used tomakeraw milk buttermilk, withspecial care. Avoidusing ultra-pasteurized or UHT milk. Reusableculture: a small amount of each batch can be used to make thenext batch and reculturesfrom batch to batch indefinitely.