This is an adaptation of the whey recipe from Sally Fallon's Nourishing Traditions. Using this method, you get wonderful cream cheese and whey, which can be used to make sauerkraut, ginger ale, or many other lacto-fermented foods.
It couldn't be easier: Put plain yogurt in a dish towel or cheese cloth and let the whey drip out overnight. I tied my dish towel together with rubber bands, and suspended it from a cabinet knob over a pitcher. Once the cream cheese and whey are separated, just save the whey in a glass mason jar, or similar. Refrigerated whey will last for months. In the images, I used goat milk yogurt. Cow milk yogurt will work fine.