The basic ingredients of yogurt consist of the desired type or combination of milks and a starter culture. Some recipes call for dried milk along with the liquid variety, with the ratio being 1 rounded teaspoon of powdered yogurt culture, 1 quart of liquid milk and 1/3 cup dried milk.
There is no specific type of milk required for yogurt. It can be raw or pasteurized, fat or non-fat, dairy or non-dairy. However, the preparer should consider the desired type of yogurt and adjust the steps of preparation in accordance with the milk selection. While freeze-dried varieties of starter cultures are readily available, the preparer can also use a store-bought yogurt to initiate the process. Criteria to take into account when purchasing starter include culturing method, flavor, consistency and bacteria count.
In addition to the perishable ingredients of milk and culture, the preparer needs several pieces of equipment. A quality, plastic container serves as an incubator for the yogurt, accompanied by an airtight cover, coffee filter or tightly weaved cloth that can be affixed to the container with a rubber band. The preparer also needs a thermometer, a pot to heat the milk and an insulator of some form. A crock pot or a thick towel can function as the latter.