A dehydrated sourdough starter looks dead — but it almost never is. The wild yeast and lactic acid bacteria are simply dormant, suspended in a dry state until you give them warmth and food. With a few days of patient feeding, a dried starter reactivates completely. Here's exactly how to do it.
Is my dehydrated starter actually dead?
Dried flakes, a hard crust, or powder are all signs of dormancy, not death. The only time a starter truly can't be saved is when you see pink or orange streaks (bacterial contamination) or fuzzy mould. If your starter is just dry and smells neutral, sour, or slightly yeasty, it's almost certainly alive and ready to revive.
Not sure what you're looking at? Run it through our free Starter Revival Wizard — it diagnoses the problem in a few clicks.
What you'll need
- Your dehydrated starter (flakes or powder)
- Unbleached flour (bread flour, or a 50/50 bread + wholemeal blend)
- Warm water, around 30°C
- A clean glass jar with a loose lid
The 5–7 day rehydration method
- Day 1 — dissolve. Put 20g of dried starter into a clean jar. Add 40ml warm water (30°C) and stir until mostly dissolved. A few lumps are fine. Cover loosely and leave at room temperature for 12 hours.
- Day 1, later — first feed. Add 20g flour and 20g water. Stir well, cover, and wait another 12 hours. You may see a few early bubbles.
- Days 2–5 — daily feeds. Each day, discard about half, then feed 30g flour + 30g water. Keep it warm (24–26°C is ideal). Activity builds gradually — small bubbles first, then a reliable rise.
- Day 5–7 — strength test. When your starter doubles within about 6 hours of feeding and passes the float test, it's strong enough to bake with.
Want the warmth-and-timing details dialled in for your kitchen? Our Starter Care Guide has a feeding calculator and a peak-rise timeline.
How to know it's fully revived
A revived starter should:
- Double in volume within 4–6 hours of feeding
- Look domed and bubbly at its peak
- Smell pleasantly tangy, not sharp or acetone-like
- Float when a spoonful is dropped into water (the float test)
Troubleshooting a slow revival
If it's sluggish after a few days, it's usually temperature. Cold kitchens slow everything down — move the jar somewhere warmer (the top of the fridge, or inside the oven with just the light on). Adding 10–15% rye flour to your feed also gives wild yeast an extra boost. For a deeper diagnosis, see our revival instructions.
Skip the wait entirely
Reviving a dried starter takes patience. If you'd rather bake this week, our Organic Sourdough Starter is preserved at peak biological activity and activates in about 2 hours — no multi-day setup required.
Explore more free calculators and guides on our sourdough tools page.
