Step 1

Clean and sanitize both the jar, the lid, and any utensils that will come in contact with the cream.

Step 2

Pour the cream into the sanitized jar. Using a sanitized spoon, stir in ½ teaspoon of the powdered mesophilic culture or 2 tablespoons of the active cultured buttermilk, and 2 tablespoons of yogurt OR omit the mesophilic culture and yogurt and just add 2 tablespoons of kefir. Stir well. Put the lid on the jar.

Step 3

Create a warm environment to culture the sour cream, as you would if you were culturing yogurt.  I place a 2-quart glass measuring cup in the oven and put about 1 liter of hot tap water into it. Place the covered jar in this and put it in the oven on the middle rack. Turn the oven light on and close the door. The oven maintains a temperature around 95 to 115 F which is ideal for dairy ferments.

Step 4

Leave the sour cream to ferment overnight – 8 to 12 hours. As it ferments it will thicken and the flavor will improve.

Step 5

Refrigerate the finished sour cream.