Sourdough Starter Not Rising? A Repair Guide

A stalled starter feels mysterious and almost never is: yeast is a population, and populations grow when temperature, food and water are right. Run the five checks below in order - each one maps to a fix you can apply today. The feeding arithmetic is the starter calculator's job; the hydration guide covers why flour and water ratios matter so much to everything downstream.

1. Temperature: the top suspect

Wild yeast works happily at 24-28 °C and barely works below 18 °C. A winter kitchen at 17 °C can make a healthy starter look broken - the same slowdown the winter fermentation guide documents for every ferment. Move the jar somewhere warm (top of a fridge, oven with the light on, inside a microwave with a mug of just-boiled water) and watch the same jar double within hours.

2. Feeding ratio: food per yeast

The classic 1:1:1 feed (starter : flour : water, by weight) gives the culture a comfortable meal. A jar fed 1:5:5 gets fresher food per cell and rises slower but stronger - the right medicine for a sour, acidic, exhausted culture. The calculator turns any ratio into grams; the principle is that more fresh flour relative to starter wakes a sluggish jar, while less suits a vigorous one on a tight schedule.

3. Flour: food quality

All-purpose flour works, but whole grain flour - rye especially - carries more minerals and enzymes and reliably wakes a tired culture. If a starter refuses to rise on white flour, one or two feeds with 50% whole rye usually change the picture. Bleached flour is the only genuinely bad choice: the treatment strips the nutrients yeast feeds on.

4. Water: the quiet killer

Heavily chlorinated tap water can hold a culture back without ever killing it. Let tap water sit uncovered for a few hours so chlorine off-gasses, or use filtered water for a week and compare. This check costs nothing and solves a surprising share of "nothing works" cases.

5. Time: the honest reset

After any change, a starter needs 2-4 feeds at consistent warmth before judging the result. Switching flour, ratio and location all at once is fine; switching them every 12 hours makes diagnosis impossible. Pick warm, pick 1:1:1 with a rye component, feed twice a day, and read the jar on day three, not day one.