A dormant sourdough starter is almost never dead — it's just hungry. Even after months in the fridge, weeks forgotten on a counter, or years tucked into a jar of dried flakes, you can usually revive it with three days of patient feeding and a warm spot on the kitchen counter. Here's how to wake yours up gently, whatever state you've found it in, and how to tell when it's safely back.
Is your starter actually dead? (the diagnosis)
Before you do anything else, pause. A sourdough starter is one of the most resilient things in your kitchen, and the chances are very good — very good — that what you're looking at is just a hungry starter that needs a feed. The next five minutes are about reading the jar.
The four things you're looking at — hooch, skin, mould, smell
What does a dead sourdough starter look like?
A truly dead sourdough starter has fuzzy mould — distinct fluffy spots of pink, orange, blue, green or black — growing on the surface or up the sides of the jar. A dormant starter, by contrast, looks unsettling but ordinary: dark brown liquid (hooch), a grey-tinged skin, a flat surface, and a sharp alcohol or vinegar smell. Mould is the only sign that means start again.
- The liquid on top (hooch). Clear to amber after a week, getting darker (stout-coloured to nearly black) the longer the starter has gone unfed. Hooch is alcohol — a sign of fermentation, not death. Stir it back in for a milder result, or pour it off if it's very dark.
- The skin or crust on top. Old starters develop a grey or beige skin, sometimes corrugated. Peel it off; the cream-coloured starter underneath is what you're working with.
- The smell. Sharp alcohol, vinegar, even a faint nail-polish whiff are all fine — those are fermentation by-products. Genuinely rotten, putrid, or sewage smells are different (and rare).
- Mould. Fuzzy spots of pink, orange, blue, green or black on the surface or up the sides. This is the only deal-breaker.
Pink, orange or fuzzy: when to bin it
How do I know if I've killed my sourdough starter?
A sourdough starter is dead only if it has visible mould — fuzzy patches in pink, orange, blue or green — or if it smells genuinely rotten rather than sharply alcoholic. Dark hooch, vinegar smells, a grey skin, or even a faint acetone whiff all mean the starter is starving, not dead. Bin a mouldy starter without trying to rescue it; feed any other state.
| Visual | What it is | What it means | What to do |
|---|---|---|---|
| Dark brown liquid on top | Hooch (alcohol) | Starving, very normal | Stir in or pour off; feed |
| Grey corrugated skin | Oxidised surface | Long fridge stint | Peel off; feed underneath |
| Fuzzy pink or orange patch | Mould | Contamination | Bin everything; sterilise jar |
| Fuzzy green / blue / black patch | Mould | Contamination | Bin everything; sterilise jar |
If you've ruled out mould, your starter can almost certainly be revived. The route depends on how it's been stored — and that's the next four sections. Or use the route selector below.
Revival Route Selector
Pick where your starter was kept and for how long. We'll give you the protocol and the expected timeline.
Reviving from the fridge (1–4 weeks of neglect)
How do I bring a sourdough starter back to life?
To bring a sourdough starter back to life, pour off any dark liquid on top, scoop 25 g into a clean jar, and feed it 100 g of warm water and 100 g of strong white bread flour. Leave it at 20–22°C for 12 hours. Repeat the feed. Most starters that have lived in the fridge for under six weeks revive after two feeds; older ones may need four or five.
If your starter has been in the fridge for a few weeks and you're feeling guilty — don't. The fridge is where most sourdough starters live, and a few weeks of neglect is well within what a healthy culture handles.
The two-feed protocol
How do I wake up my sourdough starter from the refrigerator?
Take the sourdough starter out of the fridge and let it warm up on the counter for an hour. Stir the hooch back in (or pour it off if it's blackish). Discard most of the jar, leaving 25 g. Feed with 100 g warm water (around 30°C) and 100 g flour. Wait 12 hours. Feed again at the same ratio. After the second feed, a healthy starter will double within 8 hours.
- Take the jar out of the fridge. Let it sit on the counter for an hour to warm up.
- Stir the hooch back in, or pour it off if it's very dark. Don't worry which.
- Tip most of the starter out (compost it, or set aside for discard recipes). Leave about 25 g in the jar.
- Add 100 g of warm water (around 30°C, no hotter — hot water will harm the yeast) and 100 g of strong white bread flour. Stir. Cover loosely.
- Leave on the counter at 20–22°C for 12 hours.
- Repeat the feed: discard down to 25 g, add 100 g warm water and 100 g flour.
- After this second feed, watch for it to double within 8–12 hours.
Why warm water matters in a 16°C UK kitchen
A February kitchen in the north of England can sit at 13–15°C, which slows yeast recovery sharply. Warm feed water (around body temperature, 30°C) gives the culture a temporary lift. Vanessa Kimbell at The Sourdough School — the UK authority on starter care — recommends 35°C feed water for white starters, slightly warmer than our 30°C suggestion; both work, and if your kitchen is cooler, push toward her number.
Reviving from longer neglect (1–6 months in the fridge)
Three months. Six months. We've seen worse. A slightly bigger rescue feed, same shape, but three feeds expected.
The three-feed protocol
Same setup as the two-feed version — pour off dark hooch, leave 25 g, feed with 100 g warm water and 100 g flour. The difference is repetition: feed at 12-hour intervals, three times, before judging.
The first feed will look like nothing's happened. That's normal. Gänzle and Vogel's lactobacilli review explains why: yeasts wake faster than the lactic bacteria, so bubbles arrive before smell does. Two more feeds and the smell shifts.
What hooch the colour of stout means
Dark almost-black hooch is just oxidised alcohol — old fermentation by-products. Pour it off, don't stir it in. The starter's pH at this point is likely below 3.5; the first big feed dilutes the acidity and lets bacteria reproduce again. Buehler's Bread Science Chapter 4 maps the pH recovery curve in detail.
Clara: a customer named Helen sent us a jar nine months out of her fridge for diagnosis. She'd named the starter Gerald and was ready to bin him. We gave him three feeds in our Somerset kitchen at 22°C and on day four Gerald rose by 80% in seven hours. We posted him back. Gerald lived.
Reviving from dried or dehydrated starter
Can a sourdough starter dry out and come back?
Yes — a dried sourdough starter can come back to full activity, and dried flakes stored airtight stay viable for years. Crumble 10 g of flakes into 50 g of warm water, leave for an hour to rehydrate, then add 25 g of flour. From there, feed it 1:1:1 every 12 hours. Expect first signs of bubbling within 48 hours and a fully bakeable starter in 5–7 days.
Rehydrating the flakes
- Crumble 10 g of flakes into a clean jar.
- Pour 50 g of warm water (30°C) over them. Stir gently to break up clumps. Cover loosely. Leave for 1 hour.
- Stir in 25 g of strong white bread flour. Cover. Leave at 20–22°C.
- After 24 hours, feed with 25 g flour + 25 g water.
- Continue 12-hourly feeds at 1:1:1 for 4–6 more days.
The 5–7 day timeline
By Day 5–7, the starter should double within 8 hours of a feed. That's bakeable. If you'd like to dry a portion of your active starter as backup, our guide to dehydrating sourdough starter shows you how.
Reviving from frozen
Frozen starter is a strange middle ground — colder than fridge, more dormant than dried. Most people freeze a portion as a backup. Reviving from frozen is gentler than from dried, but slower than from fridge.
Thawing without shocking the yeast
- Take the frozen portion out and place it on the counter — never in the microwave or warm oven. Let it thaw at room temperature for 4–6 hours.
- Stir it well. It will look watery. That's normal — ice crystals damage some cell walls.
- Feed at 1:1:1 (25 g starter + 25 g water + 25 g flour). Leave 12 hours.
- Repeat 12-hourly feeds for 3–5 days.
- Expect first visible bubbles by 36 hours, full doubling by day 4 or 5.
Why frozen revival is a longer wait than fridge revival
Freezing damages some Lactobacillus cells, so the bacterial population has to rebuild. The yeasts handle freezing better than the bacteria do. That's why a frozen starter bubbles fairly quickly but takes longer to smell properly yoghurty.
Signs of recovery — Day 1, Day 2, Day 3
Day 0 — just fed
Loose, smooth, slightly cloudy. Smells of flour and water with whatever yeasty/vinegary note carried over.
No bubbles yet.Day 1 — after first feed
Surface flat or with a few isolated bubbles. Volume unchanged. Smell turns sharper — sometimes a brief nail-polish note as alcohol releases.
This is good.Day 2 — after second feed
Surface visibly bubbly, possibly a small dome. Volume up 30–50%. Smell shifts: less alcohol, more vinegar-yoghurty.
Almost there.Day 3 — after third feed
Domed top, surface a network of bubbles big and small, volume doubled within 8–12 hours of feeding. Smell sweet-yoghurty.
Bakeable.When you see the Day 3 signs, your starter is back. Give it one more feed before baking with it — a freshly-fed, just-peaked starter is what every good loaf wants.
UK kitchen temperature and revival timing
Doubling times approximate, based on Sourdough Hub bake logs and Met Office UK regional climate data.
When to give up and start over
After three or four full days of twice-daily feeds, if there are no bubbles, no smell change, no movement at all — it's time to let go. This is rare, but it happens, particularly with very old dried starter that wasn't stored airtight, or with a frozen portion that thawed and refroze in a freezer that drops out of routine. Start fresh.
Our Express Sourdough Starter Kit ships a live, active starter that's ready within hours of arrival, so you can be baking by the weekend.
Frequently asked questions
How long does it take to revive a dormant sourdough starter?
Two to three days for a starter from the fridge, five to seven days for a dried one, three to five for a frozen portion. The most reliable signal is doubling within 8–12 hours of a feed — when you see that, the starter is ready to bake with.
Is dark or black liquid on top of my sourdough starter a sign it's dead?
No. That's hooch — alcohol from fermentation that's gone darker as it oxidises. It looks alarming and smells sharp, but it just means the starter is hungry. Stir it back in or pour it off, then feed your starter.
What does dead sourdough starter look like?
A dead sourdough starter has visible mould — fuzzy patches of pink, orange, blue, green or black on the surface or up the sides of the jar. Dark liquid, a grey skin, or strong alcohol/vinegar smells are not signs of death; they're signs of hunger.
Can a sourdough starter dry out and come back to life?
Yes. Properly dried sourdough starter, stored airtight, stays viable for years. To revive it, crumble 10 g of flakes into 50 g of warm water, rest for an hour, then feed with 25 g of flour. Continue twice-daily 1:1:1 feeds for five to seven days.
What temperature does a sourdough starter need to revive at?
20–22°C is ideal. Below 16°C — common in UK kitchens in winter — slows revival by roughly 30–50%. If your kitchen is cool, use warm feed water (around 30°C, no hotter) and stand the jar on top of a fridge or near a radiator, never on it.
Should I throw away the discard when reviving a sourdough starter?
The first discard from a long-neglected starter is best composted — it's likely over-acidic and old. From the second feed onward, the discard is fine to save in the fridge and use in pancakes, crackers or flatbreads. We have a guide to sourdough discard recipes you can browse.
Why isn't my revived starter rising even after three feeds?
Usually one of three things — your kitchen is too cool (under 18°C), your flour is very white and low in microbes, or the starter needs more feeds than three. Switch to stoneground wholemeal or rye for one or two feeds; the extra microbes accelerate recovery. If after seven days there is no visible activity, see our "when to give up" section.
What's next
Once your starter is back, the feeding schedule takes over. If it's wobbly and you can't tell why, the troubleshooter walks ten reasons starters go quiet. Want to dry a portion as backup? Our guide to dehydrating and storing covers it. And the complete UK guide to sourdough starters is the pillar that ties everything together.
