Here is a simple, economical way to make yogurt and kefir at home using fresh ingredients, without the additives, preservatives or sugars found in many store-bought options. The insulated maker is designed to maintain the consistent temperature needed for the yogurt or kefir to culture and requires only two ingredients – milk and a starter (use a small amount of store-bought plain yogurt/kefir, a powder starter or kefir granules).