Dough Dough 24-Hour Sourdough and Kefir Starter Kit – Artisan Bread and Probiotic Drink Mix. Comparison chart for Dough Dough dual-life starter vs standard sourdough and kefir grains. While standard sourdough and kefir grains can take up to a week to revive and require high maintenance, our bio-diverse formula is ready in just 24–48 hours.