Sourdough Starter Hooch and What to Do With It

A smooth liquid layer on a familiar, established sourdough starter can be hooch, a by-product of fermentation that may collect when a jar has been left unfed. In a new or weak starter, clear liquid can also be water separating out. Check the jar’s recent rise and feeding history. If you find mould, suspicious pink or orange streaks, or unusual growth you cannot identify, discard the whole culture. [1] [2] [3]

Keep, check or discard

Situation	Next step
Established starter rose and fell after its last feed. A smooth liquid layer appeared during a long gap.	Inspect for signs of contamination. If everything else looks familiar, refresh it using your normal routine.
New jar shows a clear layer but has yet to rise dependably.	Record where the liquid sits and what happened beforehand. Water separation is possible. Follow the creation method if there are no signs of spoilage.
Jar has fuzzy growth, suspicious coloured streaks, an unidentified film or a change that makes you suspect contamination.	Discard all the starter, then thoroughly clean and rinse the jar.

Look before stirring. Once the liquid is mixed in, you lose one of the easier observations. A smooth layer can have more than one cause, and a photograph has no record of what happened between feeds. Keep raw starter out of taste tests. [1] [4]

Why does a mature starter get liquid on top?

An established starter can develop a liquid layer after sitting unfed. It may smell alcoholic and can darken in a refrigerated jar. Note how long it has been since the last feed and whether you saw a familiar rise and fall beforehand. A clear layer in a jar that has barely risen has a different history from a dark layer on a mature starter that has been in the fridge for a while. [1] [2] [3]

Suppose you inspect a jar that rose after its last feed and was left in the fridge longer than planned. You find smooth grey liquid and no separate signs of spoilage. Hooch is plausible. Compare that with a new jar that has barely moved and shows a clear layer shortly after mixing. Keep the observation with that day’s feed rather than treating it as proof that the young starter needs an extra feed.

The three observations worth keeping

Write down the last feed time, the most recent rise you actually saw and where the liquid appeared. “Fed Sunday, rose and fell before refrigeration, smooth layer on Friday” gives you a clearer comparison than “liquid in jar”. If the starter has a suspicious patch, skip the logging experiment and discard the culture. [1] [3]

Should I pour off the hooch or stir it in?

For an otherwise normal established starter, Colorado State University Extension describes either option. Then feed the starter according to your usual method and watch for a familiar rise. Pouring off a liquid layer cannot salvage a jar with suspected contamination. If you see signs of spoilage or you remain unsure about an unusual patch, discard the whole starter. [1]

If the same change keeps appearing earlier than you expect, compare the dates, feed ratios and temperatures. Try one change to your routine and see whether it shifts the pattern. Crispy Crust’s planned starter history would let you record surface liquid beside those conditions. The useful bit is knowing what happened before it appeared.