# Sourdough Starter: A Microbiologist's Notes
I'm a microbiologist who bakes. These are the notes I wish someone had given me — the science behind what actually matters and what's ritual.
## What's actually happening
Your starter is an ecosystem of ~30 species competing for resources. Two groups dominate:
**Wild yeast** (*Saccharomyces* and *Kazachstania* species) — produce CO₂ (leavening) and ethanol. They prefer slightly acidic environments (pH 4–5) and thrive at 25–28°C.
**Lactic acid bacteria** (LAB, primarily *Lactobacillus* and *Leuconostoc*) — produce lactic acid and acetic acid. T
sourdough-science.md