Glossary
Hooch
A layer of dark, alcoholic liquid that forms on top of a starter when it has gone a long time without fresh flour.
Hooch is the thin layer of liquid, often gray or brown and sharply alcoholic-smelling, that can form on top of a sourdough starter when it has been left too long between feedings. It is a natural byproduct of fermentation and simply means the yeast has run out of fresh food and is producing alcohol as it slows down.
Seeing hooch is not a sign that a starter is ruined, but it is a clear signal that it is hungry and overdue for a feeding. Depending on preference, some bakers pour the hooch off before feeding for a milder flavor, while others stir it back in for a sharper, more sour result; either approach works as long as a normal feeding follows soon after.
No special equipment is needed to deal with hooch beyond the jar the starter already lives in, though a jar with clear sides makes it easy to spot forming before it gets thick. A common mistake is treating regular hooch as a sign the starter has failed and starting over unnecessarily, when a feeding or two back on a regular schedule is usually all it takes to bring it back to normal activity.