Keeping a Sourdough Starter Alive
A sourdough starter is a living colony of wild yeast and bacteria. It's not fragile, but it does need a rhythm. Get the rhythm right and it runs itself for years.
What you're managing, not babying
A sourdough starter is forgiving. It can survive neglect, temperature swings, and a missed feeding. What it needs is a predictable pattern you can actually keep. That matters more than perfection.
- A glass jar or clear container (at least 1 quart)
- A kitchen scale (optional but useful)
- A spoon for stirring
- Cloth or coffee filter to cover the jar (not airtight)
What goes in.
- 1 partactive starter
- 1 partwhole wheat or all-purpose flour
- 1 partfiltered or tap water
Feed-to-bake cycle matching
The single thing that keeps a starter alive long-term is feeding it on a schedule that aligns with your actual baking. If you bake weekly, feed weekly. If you bake monthly, refrigerate it and feed monthly. A starter fed every other day when you only bake quarterly will exhaust you. Match the feeding schedule to your life, not to some ideal.
The method.
Establish a feeding schedule that matches your baking frequency
If you bake weekly, feed your starter once a week. If you bake every two weeks, feed every two weeks. If you bake once a month, store it in the fridge and feed once a month. Write the schedule down or set a phone reminder. Consistency matters; frequency doesn't.
Remove the starter from the fridge (if stored cold) and let it come to room temperature
If your starter has been refrigerated, take it out 30 minutes before feeding. You don't need to wait until it's exactly room temperature—30 minutes is enough. Cold starter will still work; room temperature just speeds up the process.
Discard half the starter before each feeding
Scoop out and throw away half of what's in the jar. This step prevents the jar from overflowing and resets the ratio. You're always feeding a manageable amount. (Save the discard for pancakes, crackers, or other recipes if you want to avoid waste.)
Feed with equal parts flour and water
Add roughly equal weights of flour and water to what remains. If you have 100g of starter, add 100g flour and 100g water. Stir until there are no dry pockets. The texture should be thick but pourable, like thick batter. You don't need a scale—use volume if that's easier (one part starter, one part flour, one part water works fine).
Cover loosely and leave at room temperature
Cover the jar with a cloth, coffee filter, or paper towel secured with a rubber band. Don't seal it; the starter needs air. Leave it at room temperature (65–75°F is ideal, but 60–80°F works). Within a few hours you'll see bubbles. By the next day it should show a dome or a slight separation on top—that's the yeast and bacteria at work.
Use the starter when it's at peak or store it for later
Peak activity is 4–8 hours after feeding when the surface is bubbly and it smells sharp and sour. Use it for baking at this point. If you're not baking immediately, cover it and refrigerate after it peaks. It will sleep in the cold and stay alive for weeks between feedings.
Return the starter to the fridge if you're not baking soon
Refrigerated starter can sit for 2–4 weeks before the next feeding. When you're ready to bake again, pull it out, let it warm to room temperature, feed it, and proceed. It may look sad in the fridge—a thin brown liquid on top is normal. Stir it back in or pour it off; either way the starter is fine.
Other turns to take.
Room-temperature maintenance (frequent baker)
If you bake 2–3 times a week, keep the starter at room temperature and feed it daily or every other day. This is simpler in terms of scheduling (same time each day) but requires more attention. Use the starter at peak, feed again, repeat.
Cold storage (occasional baker)
If you bake once a month or less, keep the starter in the fridge permanently. Feed it once a month or whenever you plan to bake. Pull it out, feed it, let it peak at room temperature (4–12 hours), then use it. Return to the fridge after baking.
The dry starter backup
Spread a thin layer of healthy, active starter on parchment paper and dry it completely at room temperature (1–2 weeks). Once fully dry, break it into pieces and store in an airtight container. Dried starter lasts for months and can be rehydrated with water and flour if your liquid starter fails or if you want a backup.
When it doesn't go to plan.
A starter that looks neglected—brown liquid on top, sparse bubbles—often just needs a feeding. Brown liquid is normal and not a sign of failure.
If your starter hasn't bubbled after 24 hours, the room might be too cold. Move it to a warmer spot or wait another 12 hours. 65°F is the minimum; 70–75°F is ideal.
The white, fluffy 'hooch' (liquid) that appears is alcohol from fermentation. You can pour it off or stir it back in—both are fine. Some cooks prefer to stir it in for extra strength.
If mold appears (fuzzy, colored growth), discard the starter and start over. A bit of pink or orange tinge can sometimes be saved by discarding the affected portion and feeding well, but mold is not salvageable.
Feeding with whole wheat or rye flour occasionally (once a month) can boost a sluggish starter. These flours have more bran, which feeds the microbes. But all-purpose works fine long-term.
A starter can survive in the fridge for 2–3 months without feeding. It might look terrible when you open the jar. Feed it well twice before trusting it to bake again.
Use chlorine-free water if possible—chlorine can slow fermentation. Tap water that's sat for a few hours works. Filtered water is safest.
Don't refrigerate immediately after feeding. Let it sit at room temperature for 2–4 hours so it can ferment and build strength before the cold slows it down.
The ones that keep coming up.
How long does a sourdough starter actually last?
Decades, if you keep feeding it. Starters have been passed down for generations. The microbes regenerate with each feeding, so as long as you feed it, it lives.
What if I forget to feed my starter for a month?
It may look grim—thin, brown, smelly—but it's usually alive. Feed it, wait 12 hours, feed again, and check for bubbles by the third feeding. Most starters recover. If after three or four feedings there are still no bubbles, it's dead and you start fresh.
Can I use tap water or does it have to be filtered?
Tap water usually works fine, especially if it's been sitting for a few hours (chlorine evaporates). If your tap water is heavily chlorinated or treated, filtered water is safer. Bottled or boiled water both work.
My starter smells like nail polish remover. Is it bad?
No. That's acetone from fermentation—a sign of hungry bacteria. Feed it and the smell should fade. If it persists and smells rotten (not sour), that's a bad sign, but pure solvent smell is normal.
Do I have to discard half before each feeding?
Not technically, but your jar will overflow and you'll waste flour. Discarding half keeps the ratio manageable. Or use the discard in other recipes—pancakes, crackers, waffles—and waste nothing.
How do I know if my starter is ready to use for baking?
Look for bubbles throughout, a dome shape on top, or a slightly puffed surface. Smell it—sour and yeasty is good. Doubled in size or showing signs of fall (bubbles on the way down) is also ready. Peak is within 4–8 hours of feeding at room temperature.
Can I store my starter in a plastic container instead of glass?
Yes, but glass is better. Plastic can scratch over time and harbor bacteria in the cracks. Glass is easier to see through and lasts forever.
What ratio of starter to flour to water should I use?
Equal parts by weight (1:1:1) is the simplest and most reliable. If you have a scale, use it. If not, a visual ratio of equal volumes works—one part starter, one part flour, one part water.