Part of: Fermentation School
A sourdough starter is a living culture. Like any living thing, it needs regular attention. But “regular” doesn’t have to mean “rigid.”
This guide gives you a maintenance system that works with your schedule—not against it.
The Core Concept: Feed Before It Starves
Your starter is a colony of wild yeast and bacteria. They eat flour and water. When they run out of food, they slow down, weaken, and eventually die.
The rule: Feed your starter before it exhausts its food supply.
That’s it. Everything else is detail.
The Simple System
If You Bake Weekly (Room Temperature)
Keep your starter at room temperature. Feed it once a day, or every 24 hours.
The process:
- Discard most of the starter (keep about 25g or 2 tablespoons)
- Add equal parts flour and water by weight (typically 100g each)
- Mix until no dry flour remains
- Cover loosely (cloth, lid askew, or plastic wrap with holes)
- Wait 12-24 hours before the next feed
Signs it’s ready to feed:
- Bubbles throughout
- Doubled in size (or more)
- Pleasant sour smell
- Starts to deflate or form a “dome” on top
If You Bake Occasionally (Refrigerator Storage)
Keep your starter in the fridge. Feed it once a week.
The process:
- Remove from fridge
- Discard most (keep 25g)
- Feed with fresh flour and water (100g each)
- Let sit at room temperature for 2-4 hours (until it shows activity)
- Return to fridge
Before baking:
- Take the starter out
- Feed it 1-2 times at room temperature (12-24 hours apart)
- Use when it’s at peak activity (doubled, bubbly, domed)
The Flexible Approach
What If I Miss a Feed?
Room temperature starter:
- Missed 1 day: Feed as normal. It may smell extra sour. That’s fine.
- Missed 2-3 days: Feed 2-3 times over 24 hours to revive.
- Longer: See the revival section below.
Refrigerated starter:
- Missed a week: Feed as normal.
- Missed 2-3 weeks: Feed 2-3 times at room temperature before returning to fridge.
- Longer: See the revival section below.
Can I Change My Routine?
Yes. You can switch between room temperature and fridge storage anytime.
To move to fridge:
- Feed your starter
- Let it sit at room temperature for 2-4 hours
- Refrigerate
To move to room temperature:
- Take starter out of fridge
- Feed immediately
- Keep at room temperature
The Flour Question
What Flour Should I Use?
Best: A mix of bread flour and whole grain (rye or whole wheat).
Why:
- Bread flour provides structure and food
- Whole grain adds minerals and enzymes that yeast love
Ratio: 80% bread flour + 20% whole grain works well.
Acceptable: All-purpose flour. It works, just slightly less vigorous.
Avoid: Bleached flour (less nutrients for yeast).
Does It Have to Be Exact?
No. Your starter is resilient. Approximate measurements are fine.
By weight (preferred):
- 100g flour + 100g water
By volume (rough):
- ½ cup flour + ½ cup water
The texture should be like thick pancake batter. Add more flour or water to adjust.
The Jar Question
What Kind of Jar?
Any clean glass jar works. Wide-mouth is easier for cleaning.
Size: At least 500ml (2 cups). Your starter will double.
Covering:
- Cloth with rubber band (breathable)
- Lid set loosely on top (allows gas to escape)
- Plastic wrap with holes poked
Don’t: Seal it airtight. The fermentation produces gas that needs to escape.
How Often to Clean?
Every 1-2 weeks, or when the jar gets messy.
Process:
- Transfer starter to a bowl
- Wash the jar with hot water (soap optional)
- Return starter to clean jar
- Feed as normal
Signs of a Healthy Starter
Visual Cues
- Bubbles: Small bubbles throughout, not just on top
- Rise: Doubles (or more) within 4-8 hours of feeding
- Texture: Spongy, airy, not dense or flat
- Color: Creamy white to light tan (not pink, orange, or black)
Smell Cues
- Healthy: Pleasantly sour, yeasty, like yogurt or beer
- Concerning: Nail polish remover, extremely sharp acid (needs more frequent feeds)
- Bad: Rotting, moldy, foul (discard and start over)
Taste (Optional)
- Healthy: Mildly sour, pleasant tang
- Over-fermented: Extremely sour, almost painful
Reviving a Neglected Starter
The Process
- Examine: Check for mold (fuzzy, colored patches). If moldy, discard.
- Smell: Should be sour but not rotten. If rotten, discard.
- Feed: Take a small amount (even 5g) and feed with fresh flour and water
- Wait: 12-24 hours at room temperature
- Repeat: Feed 2-3 more times over 2-3 days
- Assess: If it bubbles and rises, it’s revived
When to Give Up
- Visible mold (not just liquid on top)
- Foul, rotting smell that doesn’t improve after 2-3 feeds
- No activity after 3+ days of regular feeding
It’s okay to start over. A new starter takes 5-7 days.
Common Questions
What Is the Liquid on Top?
That’s “hooch”—alcohol produced by fermentation. It’s normal.
Options:
- Pour it off (for a milder starter)
- Stir it in (for a more sour starter)
Either is fine.
Why Is My Starter So Slow?
Possible reasons:
- Too cold: Move to a warmer spot (70-75°F / 21-24°C is ideal)
- Not enough food: Increase the flour-to-starter ratio
- Young starter: New starters take time to strengthen
- Water quality: Try filtered or spring water
Can I Use Whole Grain Flour Only?
Yes, but the starter will be more acidic and may rise less predictably. A mix works better for most bakers.
Do I Really Have to Discard?
Yes, for two reasons:
- Volume control: Without discarding, you’d have exponential growth
- Fresh food: Removing old starter makes room for fresh flour and water
But don’t throw it away: Use discard in pancakes, flatbreads, crackers, or other recipes. See our Sourdough Discard Flatbreads guide.
The Bottom Line
Your sourdough starter is more resilient than you think.
- Feed it before it starves
- Keep it at a comfortable temperature
- Watch for bubbles and rise
- Don’t stress about exact timing
Once you get the rhythm, maintenance becomes second nature. And the reward—fresh, naturally leavened bread—is worth every feed.
Next Steps
- Sourdough Starter Recipe — Create your starter from scratch
- Sourdough Discard Flatbreads — Use your discard deliciously
- Fermentation School Hub — Explore all fermentation topics
