As for the two ingredients, look for milk and yogurt sourced from grass-fed cows that have never been treated with hormones or antibiotics. The reason you use pre-made yogurt in creating your own is because it contains good-for-you bacteria that will culture and ferment the milk. Once you’ve made your own, there’s no need to buy more yogurt to start another batch—just use ¼ cup of your homemade one to get the next going.
