Hooch on Sourdough Starter: What It Means

Hooch is the thin layer of liquid that collects on top of a sourdough starter, usually clear to gray, sometimes dark brown. It often smells like beer, vinegar or nail polish remover. It forms when the yeast and bacteria have eaten through the available flour and the mixture separates, leaving alcohol and acids pooled above the paste.

On its own, hooch is not mold and does not mean the starter is ruined. It is a signal that the culture is hungry, kept too warm for its feeding schedule, or mixed too wet. This page explains what to do with the liquid, how to bring the starter back to full strength, and how to adjust feeding so you see less of it.

What hooch is made of

As yeast ferments sugars from flour, it produces carbon dioxide and alcohol, while bacteria make acids. When the food runs low, activity slows, the bubbles that held the starter up escape, and the heavier flour paste sinks. The liquid left on top carries much of that alcohol and acid, which explains the sharp smell.

The color depends on flour and time. White flour starters usually show clear to pale gray hooch; whole wheat and rye starters, or starters left a long time, can turn it brown or almost black. Dark color alone is not a reason to throw the starter away.

Pour it off or stir it in

Both are acceptable. Pouring it off removes some acid and alcohol and gives a milder bread flavor and a quicker recovery. Stirring it in keeps the acid in the culture, which some bakers like for a tangier loaf, though the starter may take an extra feeding to bounce back.

When the starter is very neglected and the hooch layer is thick, pour it off. Then discard most of the remaining starter before feeding, so the fresh flour is not overwhelmed by acid.

Bringing the starter back

Keep about 20 g of the paste from the bottom of the jar and discard the rest or use it in a discard recipe. Feed it with 100 g flour and 100 g water at around 24°C (75°F). Repeat every 12 hours, or as soon as it peaks.

Most starters regain full strength within one to three days. They are ready to bake with when they reliably double within 4 to 8 hours after feeding and smell pleasantly sour and yeasty rather than sharp.

Why it keeps coming back

Frequent hooch means the culture finishes its food long before the next feeding. The fix is to rebalance food, temperature and timing.

• Room-temperature starter fed once a day in a warm kitchen: feed twice a day or use a 1:5:5 ratio
• Refrigerated starter left for more than a week: hooch is expected; feed weekly or accept the extra recovery step
• Very wet starter above 100 percent hydration: reduce the water to 80 percent to slow fermentation
• Mostly whole grain or rye flour: these ferment fast; switch some feeds to white flour

When the liquid is not hooch

A separated starter with liquid on top is normal. Visible fuzz, raised spots of white, green, blue or black, or pink, orange or red streaks are signs of mold or unwanted bacteria. Do not pour those off and carry on; discard the whole starter and clean the jar thoroughly.

A dry, darkened crust on the surface of a refrigerated starter is just dried paste. Lift it off, take fresh starter from underneath, and feed.

Common questions

Is the alcohol in hooch a problem in baked bread?

No. The amount is small and evaporates during baking. Pouring hooch off simply gives a milder flavor and faster recovery.

Can I bake with a starter that just had hooch?

You can, but the bread may rise slowly and taste sharp. Give it at least one or two feedings and use it when it has doubled and still has a domed top.

How do I stop hooch forming in the refrigerator?

Feed it with a stiffer mix before chilling, about 60 to 70 g water per 100 g flour, and refresh it weekly. A firmer starter ferments more slowly and holds its food longer in the cold.