Standard sourdough maintenance protocols are inherently wasteful. The classic "1:1:1" feeding ratio—where you discard half your starter to feed the rest—is a relic of a time when flour was cheap and understanding of microbiology was poor. Over the course of a year, a conscientious home baker following these rules will throw away kilograms of high-quality grain.

While the terms are often used interchangeably, a "Starter" (or Mother) is the perpetual culture you maintain in a small jar, fed daily to keep it alive. A "Leaven" (or Levain) is an offshoot of that starter.