1:1:1 by weight
Starter, ferment, bake
A sourdough starter is a live culture of wild yeast and lactobacillus bacteria that leavens bread and sours it at the same time. This page walks through feeding the starter, reading fermentation time against flavor and keeping quality, and correcting the mistakes that flatten a first loaf.
1:1:1 by weight
Wait for the dome
24 h vs 48 h
Trap the gas
Covered pot
Wait before slicing
It is a maintained culture of wild yeast and lactobacillus bacteria living in a flour-and-water paste.
A starter is the leavening agent itself, not a flavoring added to dough. Wild yeast produce carbon dioxide that lifts the bread, while lactobacillus bacteria produce lactic acid, which is what makes the crumb taste sour.
Because both organisms live in the same paste, the starter has to be refreshed — fed — on a regular schedule. Skipping feeds lets acid build up until the culture turns sluggish and the bread stops rising.
The starter is also the reason sourdough keeps better than yeasted bread: the acid environment created during fermentation slows the spoilage that normally stales a loaf within a day or two.
Discard most of the culture, then add fresh flour and water in equal weights and let it rise until domed.
A working routine is simple: keep a small amount of starter, add an equal weight of flour and an equal weight of water, stir, and leave it at room temperature until it doubles and domes. That peak is when the culture is strongest.
Timing depends on room temperature. At around 24 °C a 1:1:1 feed typically peaks in 4–8 hours; in a cooler kitchen it can take 12 hours or more. The schedule matters less than catching the starter near its peak.
If the starter is kept in the fridge between bakes, take it out a day ahead and give it two or three feeds before mixing dough. A cold, unfed starter is the single most common reason a first loaf comes out dense.
Longer fermentation produces more lactic acid, which sharpens the sour taste and slows staling.
Fermentation time is the main dial a home baker can turn. A short ferment — roughly 12 to 24 hours total — gives a mild tang and a tender crumb. A long ferment of 36 to 48 hours pushes the acid further and the loaf stays fresh noticeably longer.
The trade-off is dough strength. Past a certain point the acid starts breaking down gluten, so an over-fermented dough spreads instead of holding shape. The table below maps the practical windows.
Keeping quality follows the same curve: the more acid developed during fermentation, the slower the crumb dries and molds, because the acid environment is hostile to spoilage organisms.
Three stages, one loop: each one sets the conditions for the next.
Dense, flat, or gummy results almost always trace to a weak starter or a misjudged proof.
A dense loaf usually means the starter was not at peak activity when it went into the dough, so there was not enough yeast to raise it. The fix is more feeds and a warmer spot, not more flour.
A flat loaf that spreads rather than rises usually means the dough was over-proofed: the gluten network was already breaking down before baking. Shortening the bulk ferment or chilling the dough restores structure.
A gummy crumb is often a slicing problem rather than a baking problem — cutting into a hot loaf smears the interior. Waiting until the loaf is fully cool gives a cleaner crumb.
| Fermentation time | Sourness | Keeping quality | Best for |
|---|---|---|---|
| 12 h | Mild | 1–2 days | First bakes, tender crumb |
| 24 h | Moderate | 2–3 days | Everyday loaf |
| 36 h | Pronounced | 3–4 days | Deeper tang, sturdier dough |
| 48 h | Strong | 4–5 days | Long-keeping rustic loaf |
| Over 48 h | Sharp, sometimes harsh | Variable | Only with strong flour and cool temperatures |
Background facts on sourdough as a leavening agent, its starter culture, lactic acid, and keeping qualities follow the Wikipedia article on sourdough (fetched 2026-10-28).