How to Revive an Old Sourdough Starter (Black Hooch and All)

That dark, almost-black liquid sitting on top of your forgotten starter looks alarming — like the jar gave up while you were busy. Take a breath: it's almost certainly not dead. What you're looking at is hooch, the by-product of a very hungry starter, and it's one of the easiest problems in sourdough to fix.

Most sourdough starters can be saved. This page walks you through reviving an old sourdough starter in about two days.

Help, my starter formed black liquid

When a starter is left in the fridge for weeks or months without food, the microbes keep fermenting until they exhaust the available sugars. What's left behind is a layer of hooch — grey, yellow, brown or that dramatic dark purple-black, depending on how long it's been. It can smell like nail-polish remover or acetone. Both are starvation, not spoilage.

The rule is simple: as long as there's no fuzz, the starter is fine. If you see fuzzy mold or pink/orange streaks, toss it entirely — that's a real problem (see the moldy starter guide). But plain hooch, even dark hooch, is just hunger.

How to revive an old sourdough starter

You'll need a clean jar, flour and water — nothing more.

1. Pour off the hooch. Discard as much of the dark liquid as you can.
2. Discard most of the starter. Keep only a small portion — say 50 g — in a clean jar. This rebalances the acid-diluted culture.
3. Feed it big. Add roughly 100 g of flour and 100 g of water to that 50 g, mix to a paste and leave it at room temperature for about 12 hours. This generous ~1:5:5 feed is what resets a neglected culture.
4. Feed again. Take 50 g from that jar, put it in a clean jar, and feed it another 100 g of flour and 100 g of water. Leave it another 12 hours.
5. Check for a double. After the second feed the starter should double and look bubbly. If it does, it's ready to use again. If not, repeat step 4 every 12 hours until it springs back.

In most cases one or two feeds is all it takes. A starter that was only mildly neglected might recover in a single feeding; one that's been ignored for months may need a couple of days.

Best tips for reviving a starter

• Pour off the hooch for a revival rather than stirring it in — a cleaner start means faster recovery.
• Add the water first and give the jar a shake before adding flour, to loosen the dried edges and wake the wild yeast.
• Keep it warm. Room temperature (about 75°F / 24°C) speeds recovery dramatically. A warm spot makes the difference between one feed and several.
• Make a backup once it's healthy. Once your starter doubles reliably again, dry a portion or keep a cold spare jar so this never costs you weeks.

A note on patience

A revived starter is often a little wobbly for the first feed or two, then gets strong quickly. Don't judge it on cake-like rise and fall — judge it on whether it's climbing toward double and smelling fresh rather than sharp. If you keep feeding it every 12 hours at room temperature, it will come back. And if you'd rather not wait or you're unsure about the jar, starting fresh with the sourdough starter guide is always an option.

If your problem is a starter that's alive but never rises, that's a different issue — work through the not-rising fix instead.