Feeding Your Sourdough Starter: Ratios, Schedules, and What Actually Matters
Everything you need to know about feeding sourdough starter: 1:1:1 vs 1:5:5 ratios, how often to feed, fridge storage, what to feed with, and the signs that tell you your starter needs attention.
A sourdough starter is a living culture, and like anything living, it needs regular feeding to stay healthy and active. But "feeding" is often presented as more complicated than it needs to be — ratios, schedules, timers, flour choices — and beginners can feel anxious about getting it wrong.
Here's the good news: starters are more resilient than they seem. The basics are simple, the flexibility is wide, and once you understand what's actually happening during a feeding, the decisions become intuitive rather than stressful.
This guide covers everything: what feeding does, how to choose a ratio, when to feed, what to feed with, how to store your starter long-term, and the signs that something needs attention.
What Feeding Actually Does
When you feed your starter, you're doing three things simultaneously:
1. Providing fresh food. Wild yeast and lactic acid bacteria consume the sugars and starches in flour. Feeding replenishes the food supply so fermentation can continue.
2. Diluting accumulated acid. As bacteria ferment, they produce lactic and acetic acid. These acids build up over time and eventually become inhibitory — too much acid slows and eventually stops fermentation. Discarding and refreshing with fresh flour dilutes the acid concentration, restoring a productive environment.
3. Selecting for the right microorganisms. Regular feeding at consistent ratios and temperatures selects for yeast and bacteria strains that thrive in those specific conditions. Over time, this makes your starter more predictable and more reliable.
The "discard" portion — the starter you remove before feeding — isn't waste. It's the old culture being replaced with a refreshed environment.
Feeding Ratios: The Numbers Explained
A feeding ratio is written as starter : flour : water by weight. All three numbers are always in relation to each other.
1:1:1 — The Standard Ratio
Equal parts starter, fresh flour, and water. If you keep 50g of starter, you add 50g flour and 50g water.
- Peak timing: 4–6 hours at 22–24°C
- Best for: Daily baking, active maintenance, building up starter for a bake
- Character: More active, more sour (higher inoculation = faster acid production)
The 1:1:1 ratio is what most beginner guides recommend because it's simple and produces a predictable peak within a convenient window.
1:2:2 — The Moderate Ratio
One part starter, two parts each of flour and water. A middle ground between standard and extended.
- Peak timing: 6–8 hours at 22–24°C
- Best for: When 1:1:1 peaks too fast for your schedule, or when you want slightly less sourness
- Character: Balanced — active enough to build well, mild enough to develop without over-fermenting overnight
1:5:5 — The Extended Ratio
One part starter, five parts each of flour and water. Preferred by many professional bakers.
- Peak timing: 8–12 hours at 22–24°C
- Best for: Overnight fermentation, less frequent feeding, building milder flavor, preparing for a morning bake with an evening feed
- Character: Milder, less sour, slower to peak — also slower to over-ferment past peak
The lower inoculation in 1:5:5 means there are fewer bacteria relative to the food supply, so acid builds more slowly. This is why bakers like Maurizio Leo (The Perfect Loaf) prefer higher ratios for starter maintenance: the longer, slower peak produces more complex flavor and is more forgiving.
Choosing Your Ratio
The right ratio depends on your schedule and kitchen temperature:
| Situation | Recommended ratio |
|---|---|
| Baking today, want peak in 4–6 hours | 1:1:1 |
| Want peak in 6–8 hours | 1:2:2 |
| Feeding tonight, baking tomorrow morning | 1:5:5 |
| Hot kitchen (above 26°C) | 1:5:5 or higher |
| Cold kitchen (below 18°C) | 1:1:1 |
When in doubt, a higher ratio (more flour, less starter) gives you more flexibility — the starter can sit at peak for longer before declining.
Temperature: The Variable That Overrides Everything
Temperature controls fermentation speed more than any other factor. The same 1:1:1 feeding will peak in 4 hours at 24°C or 8 hours at 18°C.
Ideal maintenance temperature: 21–26°C (70–78°F)
Below 18°C (65°F): Fermentation slows dramatically. A 1:1:1 feeding might take 10–14 hours to peak. This isn't harmful — the starter is just cold and slow. Either move it somewhere warmer, switch to a lower ratio (1:1:1), or use the fridge for storage.
Above 26°C (79°F): Fermentation accelerates. At 28–30°C, a 1:1:1 starter can peak in 2–3 hours and decline quickly. In hot weather, use a higher ratio (1:5:5 or even 1:10:10), feed less frequently, or switch to the fridge for primary storage.
Above 35°C (95°F): Most yeast strains begin to struggle. Wild yeast dies above about 48°C. Prolonged exposure to temperatures above 35°C can permanently damage a starter.
Feeding Frequency: How Often Is Right?
Room Temperature Storage
A starter kept at room temperature needs feeding once or twice daily, depending on the temperature and ratio.
Once daily: Works well at 20–22°C with 1:5:5 ratio. Feed in the morning and use or refrigerate in the evening.
Twice daily: Necessary at warmer temperatures (24°C+) or with 1:1:1 ratio. Feed morning and evening, roughly 10–12 hours apart.
The right frequency is determined by observing your starter: it should be fed before it collapses completely from the previous feeding. Feeding at peak (when it's just domed and at maximum height) gives the best results. Feeding a deflated, acidic starter works, but consistency improves with feeding at or just before peak.
Refrigerator Storage
For most home bakers, the fridge is the right default.
A refrigerated starter needs feeding approximately once a week. The cold dramatically slows yeast and bacterial activity, extending the interval between feedings from 12 hours to 1–2 weeks without harming the culture.
How fridge storage works:
- Feed your starter at your normal ratio
- Let it sit at room temperature for 1–2 hours until you see some signs of activity (small bubbles forming)
- Refrigerate — do not wait for it to peak
- It will continue fermenting slowly in the fridge for 2–3 days, then settle into dormancy
Before baking: Remove from the fridge and give 2–3 feedings at room temperature, spaced 8–12 hours apart, before using in a recipe. This reactivation period restores full strength and predictability. The first feeding after cold storage often shows modest activity; by the second or third, the starter should be rising reliably again.
What to Feed With
Flour Choice
Almost any flour works for feeding. The choice affects your starter's behavior and flavor profile over time.
White bread flour or W700 glatt: The neutral choice. Produces a mild, balanced starter with reliable activity. Most recipes are calibrated for a white-flour starter.
Whole wheat or spelt: Adds complexity and slightly faster fermentation (more wild yeast and minerals in the bran). The starter will be more active and slightly more sour. A blend of 80% white + 20% whole wheat is a popular combination.
Whole rye (R960 or Roggenvollkornmehl): The most activating flour you can feed. Rye restarts sluggish starters, increases sourness, and dramatically speeds up fermentation. Use it to revive a neglected starter, or add a small percentage (10–20%) permanently for a more active, pungent culture.
Note: Changing flour gradually over several feedings is gentler than a sudden switch. The microbial community adapts to consistent inputs.
Water
Use unchlorinated water. Chlorine can inhibit the bacteria that make sourdough work. In most cities, filling a glass and leaving it uncovered for 30–60 minutes is sufficient for chlorine to dissipate. Filtered water is the most reliable option.
Water temperature affects peak timing: warmer water = faster fermentation. Room-temperature water is fine for most situations. If you want to control the process precisely, use water at the same temperature as your target fermentation environment.
How to Know When to Feed
Signs Your Starter Is Ready to Feed
- Peaked and just beginning to fall: The dome at the surface has flattened or slightly concaved. This is the ideal feeding moment for maximum activity.
- Hooch has appeared: A dark, liquid layer (alcohol + liquid waste from over-fermented bacteria) on top means the starter is very hungry. Stir it in or pour it off, then feed. Hooch is not dangerous — it's just a hunger signal.
- Smell has shifted to acetone or sharp vinegar: Indicates significant over-fermentation. The culture is still alive but needs feeding.
Signs It's Not Time Yet
- The starter is still rising (domed and climbing) — it hasn't peaked yet
- It was fed recently (within the last 4 hours at room temperature) and shows only early bubbling
Warning Signs: When Something Is Wrong
Hooch (dark liquid): Hunger. Feed more frequently or use a higher ratio. Not dangerous.
Sharp acetone smell: Over-fermentation. Feed sooner and consider a higher ratio or cooler location.
Pink or orange tinge: Contamination — discard completely and start over with a clean jar. Do not attempt to salvage.
Fuzzy mold growth: Discard and start over. Mold can penetrate below visible growth. Pink and orange molds are particularly hazardous.
No activity after 7+ days unfed at room temperature: The culture may have died. Try feeding twice a day for 3–4 days with rye flour added (10–20%). If no activity after that, start fresh.
Sour smell but no rise after 3 days of regular feeding: May be temperature-related (too cold), water quality issue (chlorine), or weak flour. Try feeding with a small amount of rye flour, using filtered water, and moving somewhere warmer.
Practical Maintenance: The Two Main Routines
Routine A: Daily Baker (Counter Storage)
Best for: baking 3–5 times per week
- Keep 50–100g starter in a jar on the counter
- Feed once or twice daily depending on temperature
- Use directly at peak — no reactivation needed
- Higher flour consumption but maximum convenience
Routine B: Weekend Baker (Fridge Storage)
Best for: baking once or twice a week
- Keep 100–200g starter in the fridge
- Feed once a week minimum (can go 2 weeks, but activity diminishes)
- Before a bake: 2–3 room-temperature feedings to reactivate
- Less flour consumption, more planning required
Most home bakers naturally gravitate toward Routine B as life gets busy. The fridge method is more forgiving and completely reliable with the reactivation protocol.
Use starter tracking directly in the proofit app — baking made simple.
See the sourdough app →Frequently Asked Questions
How much starter should I keep? For most home bakers, 100–150g is ideal. It's enough to maintain a healthy culture and have sufficient starter for a bake (most recipes use 50–100g) while minimizing waste at each feeding. There's no benefit to keeping large quantities unless you're baking at high volume.
Do I have to discard every time I feed? Yes, unless you're intentionally building up starter for a large bake. Without discarding, the ratio of fresh food to existing culture (and accumulated acid) shifts unfavorably. The culture becomes increasingly sour and eventually the acid concentration inhibits fermentation entirely. If you hate discarding, collect it in a separate jar in the fridge for sourdough discard recipes.
My starter hasn't risen after a feeding. Is it dead? Probably not. Check the temperature first — if your kitchen is below 18°C, the starter may simply be too cold to show visible activity. Move it somewhere warmer and wait. If temperature isn't the issue, try feeding with a small amount of whole rye flour (10–20% of total flour). Give it 2–3 feedings before concluding it's dead.
Can I use whole rye flour for all feedings? You can, but it produces a very active, quite sour starter that may not suit all recipes. Many bakers use rye permanently in small amounts (10–20%) to maintain high activity while keeping flavor manageable. Full rye maintenance works well for rye-focused baking.
What ratio should I use before baking? Build up to your bake. If your recipe needs 100g of starter at peak, use a feeding that produces at least that much plus your maintenance amount. For example, keep 20g starter and feed with 100g flour + 100g water (1:5:5), then use 100g at peak for the recipe and keep 20g as maintenance for the next feeding.
How long can I leave starter in the fridge without feeding? Up to 2 weeks reliably. Beyond 2 weeks, the culture begins to weaken and may need an extra reactivation feeding. Beyond 4–6 weeks without feeding, recovery becomes uncertain. Monthly feeding is the minimum for long-term fridge storage.
Can I freeze my starter? Yes, for long-term backup storage. Feed the starter, let it peak, then freeze in small portions (50–100g each). Thaw in the refrigerator overnight, then give 3–5 room-temperature feedings to restore full activity. Frozen starters can remain viable for 1–2 years. This is worth doing before a long holiday or as a backup of a well-established culture.