Don't Panic — A Flat Starter Is Rarely a Dead Starter
One of the most common concerns new sourdough bakers face is a starter that refuses to rise. You fed it, you waited, and... nothing. Before you toss it out, take a breath. In the vast majority of cases, a sluggish or flat starter can be revived with a few simple adjustments.
Let's walk through the most common causes and exactly how to fix each one.
1. Your Starter Is Too Cold
Symptoms: Little to no rise, minimal bubbles, sluggish activity.
Wild yeast is highly sensitive to temperature. Below 65°F (18°C), fermentation slows dramatically. Below 50°F (10°C), it can nearly stop altogether.
Fix: Move your starter to a warmer spot — the top of your refrigerator, inside your oven with just the light on, or near a warm appliance. Aim for 70–78°F (21–26°C). Use warm (not hot) water when feeding; water above 100°F can harm the culture.
2. Your Water Has Chlorine or Fluoride
Symptoms: Starter was active before, now seems sluggish after a water change.
Chlorine and chloramine in tap water can inhibit or kill the wild yeast and bacteria in your starter.
Fix: Switch to filtered water, bottled spring water, or tap water that has been left uncovered on the counter for several hours (this allows chlorine to off-gas).
3. You're Using the Wrong Flour
Symptoms: Starter has never been very active, or became sluggish after switching flours.
Heavily bleached, bromated, or low-protein flours can struggle to support a healthy culture. Whole grain flours (whole wheat, rye) are rich in natural yeasts and nutrients and can dramatically speed up activity.
Fix: Add a tablespoon of whole wheat or rye flour to your next feeding. For a gluten-free starter, make sure you're using the correct gluten-free feeding instructions.
4. Your Starter Is Hungry (Not Fed Frequently Enough)
Symptoms: Starter smells very acidic or like nail polish remover (acetone). Has liquid ("hooch") on top.
That dark liquid on top is a sign your starter has run out of food. The alcohol produced by over-fermentation is perfectly normal — it just means it's time to feed.
Fix: Pour off (or stir in) the liquid and feed your starter. If kept at room temperature, feed once or twice daily. If refrigerated, feed at least once per week. Learn more in our Troubleshooting Feeding guide.
5. You're Not Waiting Long Enough
Symptoms: You check your starter 2 hours after feeding and see no rise yet.
Depending on temperature and starter health, peak activity can take 4–8 hours (or longer in a cool kitchen). New starters that are still establishing their culture may take even longer.
Fix: Be patient. Mark the side of your jar with a rubber band after feeding and check back every hour. Track the rise and fall pattern — you want to use the starter when it's at or near its peak.
6. Your Starter Is New and Still Establishing
Symptoms: Starter arrived or was created recently and activity seems inconsistent.
Even our active, live Heritage starters may need a few days to adjust to a new environment, water, and flour. The microbial community goes through a settling-in period as the culture adapts.
Fix: Follow our Traditional Starter Feeding Instructions closely for the first week. Feed consistently, keep it warm, and give it time. Most starters normalize within 3–5 feedings.
When Should You Actually Worry?
If your starter has pink, orange, or fuzzy mold, discard it immediately and start fresh. Some dark discoloration is normal (oxidation), but bright or fuzzy growth is not.
A healthy starter should smell like: tangy yogurt, beer, vinegar, or yeasty dough. If it smells like those things, it's almost certainly alive — just in need of some TLC.
Start Fresh with a Living Heritage Starter
If you've truly given up on your current starter and want a fresh, guaranteed-active culture, explore our collection of living heritage sourdough starters. Our 233-Year-Old San Francisco Starter and 900-Year-Old Dutch Heritage Starter arrive active and ready to bake — and they've survived far worse than a cold kitchen.