How to Feed Sourdough Starter: Ratios, Tips & Common Mistakes

Anyone who’s kept a sourdough starter for more than a few days knows that feeding day can feel like a small ritual—or an afterthought that comes back to haunt your bake. The truth is, nailing the ratio matters more than most recipes let on. Getting it right means your starter doubles predictably, rises on schedule, and gives you that tangy, complex flavor that commercial yeast just can’t replicate. This guide covers exactly how to feed your starter with confidence, whether it’s sitting on the counter or waking up from the fridge.

Standard Feeding Ratio: 1:1:1 (starter:flour:water by weight) ·
Daily Feed Example: 40g flour + 40g water ·
Initial Mix: 50g flour + 50g tepid water ·
Fridge Wait: 2-6 hours to activate

How do you feed your sourdough starter?

The basic move is straightforward: add equal parts flour and water to your existing starter, stir until blended, and let it do its thing. The key is doing it by weight, not volume. A digital kitchen scale gives you the accuracy that cups simply can’t match (The Clever Carrot). If you have 40g of starter sitting in your jar, you add 40g of flour and 40g of water—that’s the 1:1:1 ratio in action.

Basic steps for feeding

• Weigh your starter jar. Note the weight.
• Add equal weight of room-temperature water. Swirl to dissolve the starter.
• Add equal weight of flour. Stir until no dry spots remain.
• Cover loosely and let rise at room temperature until doubled (4-8 hours for 1:1:1).

Water or flour first?

Most bakers add water first, then flour. This helps break up the starter more evenly and prevents clumps. The order doesn’t dramatically affect the final result, but adding water first makes stirring easier, especially with thicker starters.

Using the same jar

You can feed your starter directly in the same jar you’re storing it in—there’s no need to transfer it to a clean vessel each time. Simply weigh your jar with the starter, do the math, add your flour and water, stir, and you’re done. The only exception: if you’re combining discard from a separate jar with your active starter, you might want a larger container.

What ratio should you use to feed sourdough starter?

The 1:1:1 ratio—equal parts starter, flour, and water by weight—is the standard that most recipes default to. But it’s not the only option. Breadtopia notes that you should almost always feed at least 1:1:1 and let the starter ripen before feeding again. The ratio you choose affects how quickly your starter ferments and how tangy it becomes.

1:1:1 rule explained

Equal parts by weight means if you have 50g of starter, you add 50g of flour and 50g of water. This ratio gives you a moderate fermentation speed—typically peaking in 4-6 hours at room temperature. The Clever Carrot emphasizes that feeding by ratio rather than specific amounts lets you scale up or down based on how much starter you need for your next bake.

Feeding without a scale or in cups

If you don’t have a scale, volume measurements work in a pinch. Roughly ½ cup flour plus ½ cup water per tablespoon of starter gets you close. But be aware: measuring cups introduce variability because flour density changes with humidity and how you scoop. A scale costs under $15 and removes the guesswork entirely.

King Arthur method

King Arthur Baking Company recommends starting with 50g of starter, discarding the rest, then feeding with 50g of flour and 50g of water. This maintains a consistent 1:1:1 ratio and keeps your starter at a manageable size. For a smaller batch, scale down proportionally—25g starter, 25g flour, 25g water.

How often should you feed sourdough starter?

At room temperature, daily feeding keeps your starter active and predictable. Feed once every 24 hours if you’re baking once a week, or twice daily if you’re baking frequently and want faster fermentation. The goal, according to Sourdough Explained, is to have a starter ready to use within 8-10 hours from feeding.

Daily feeding routine

• Feed at the same time each day for consistency
• Wait until the starter has peaked (doubled, bubbly) before feeding again
• If it hasn’t doubled in 12 hours, your starter may be sluggish or your ratio needs adjusting

Zero-discard frequency

Traditional methods involve discarding half your starter before each feed, which creates waste. The zero-discard approach uses smaller, more frequent feeds to keep starter volume stable. Breadtopia describes a method where you feed at 1:1:1 but use the discard in recipes rather than throwing it away. This works well if you bake often enough to use the discard.

Maintenance schedule

If you’re not baking for a few days, move your starter to the fridge. Cold temperatures slow fermentation dramatically—you only need to feed every 1-2 weeks in the refrigerator. Before your next bake, take it out, discard most of it, and feed it fresh. Within 2-6 hours at room temperature, it should be active and ready.

How to feed sourdough starter from the fridge?

Pull your starter from the refrigerator and let it wake up at room temperature for about 30 minutes. Then discard down to 1-2 tablespoons—this removes old feed and gives the fresh flour and water room to work. Feed with equal parts flour and water by weight, using the same 1:1:1 ratio. Alexandra Cooks recommends discarding most of the jar down to a tablespoon or two, then feeding with equal parts.

Fed vs unfed before fridge

There’s ongoing debate about whether to store your starter fed or unfed. Most experts recommend storing it fed—it has more nutrients to draw from during the cold rest. However, storing unfed means less volume in the fridge and less waste when you discard. Either approach works if you’re feeding weekly; the starter survives either way.

Activation after fridge

After feeding from the fridge, wait 2-6 hours for activation. The exact time depends on your kitchen temperature and how active your starter was before refrigeration. You’ll know it’s ready when it has visibly risen, looks bubbly throughout, and passes the float test (a spoonful should float in water).

Discard amount

When waking up a cold starter, discard most of it. Keeping 1-2 tablespoons is enough to restart the culture with fresh flour and water. This might feel wasteful, but the small amount you keep carries all the beneficial bacteria and wild yeast. The discard can go into pancakes, crackers, or flatbreads.

What mistakes ruin your sourdough starter?

Most starter problems come down to three issues: wrong ratios, temperature extremes, or plain neglect. Breadtopia notes that repeated low-ratio feeds can cause the starter to starve, even though an occasional “snack” like 1:0.5:0.5 is acceptable. Temperature plays a huge role too—Sourdough Explained recommends lower ratios (1:2:2 or 1:3:3) in cold kitchens and higher ratios (1:4:4 or 1:5:5) in hot ones.

Biggest errors to avoid

• Over-discarding: Throwing away too much starter weakens the colony
• Under-feeding: Too little flour means the culture runs out of food before the next feed
• Using cold water: Tap-cold water slows fermentation significantly
• Neglecting: An unfed starter on the counter dies within a week

1/3/3 rule details

The 1/3/3 rule refers to a feeding ratio of 1 part starter to 3 parts flour to 3 parts water (or 1:3:3). This is similar to 1:1:1 but scaled up—it produces more starter while maintaining the same relative proportions. Some bakers prefer it because it gives them discard for recipes without sacrificing the ratio relationship.

Common problems and fixes

• Starter smells like acetone: Needs feeding, produces alcohol as it feeds itself
• Gray liquid on top (hooch): Sign of neglect, pour off and feed immediately
• Mold: If fuzzy, pink, or orange spots appear, start fresh—this is rare with regular feeding
• Not rising: Check temperature, ratio, and flour quality; older starters may need refreshing

The key specs table above shows how timing varies by ratio, giving you a baseline for planning feeds around your bake schedule.

Related reading: Edible Cookie Dough Recipe · How to Hard Boil Eggs

Frequently asked questions