My first starter had a name — Bubbles — and she deserved a better baker than me. For three months she sat on my Portland counter while I completely winged it. A scoop of flour whenever I remembered. A splash of water. No discard, no scale, no clue. What I got was a grayish, sour-smelling paste that rose about as enthusiastically as I do on a Monday morning. Barely. Grudgingly.
Learning how to feed sourdough starter properly changed everything. Dense, gummy loaves turned into the open, chewy crumb you see on this site’s homepage. The whole ritual? Three minutes. Tops. If you’ve already worked through my guide to getting a starter going, this is the maintenance routine that keeps it alive for years. No drama required.
What Feeding a Sourdough Starter Actually Means
Feeding a sourdough starter means removing a portion of the old culture (the discard), then adding fresh flour and water so the wild yeast and Lactobacillus have new food to ferment. A standard feed keeps all three parts equal by weight — 30 grams of starter, 30 grams of flour, 30 grams of water. The culture then rises over several hours, peaks, and is ready to use or feed again.
Think of your starter like a tiny farm in a jar. The wild yeast (Saccharomyces exiguus) and lactic acid bacteria are the livestock; flour is their feed. They eat, the jar goes quiet, and then — if you’ve done it right — the whole thing doubles like it’s showing off. Your job is simple: keep the pantry stocked and don’t let the animals starve. It’s closer to feeding chickens than chemistry. I use a cheap kitchen scale instead of a pitchfork.
Maurizio Leo of The Perfect Loaf, whose maintenance method I’ve borrowed heavily from, watches for what he calls the peak: the moment the starter stops rising and the domed top just begins to flatten. That’s your green light. Feed before it, and you’re interrupting dinner. Feed long after, and the yeast is already rummaging through the trash for crumbs.
How to Feed Sourdough Starter, Step by Step
A standard maintenance feed has five steps: weigh your empty jar’s tare or use a clean one, keep 30 grams of mature starter, add 30 grams of flour and 30 grams of room-temperature water, stir until no dry pockets remain, then mark the level and wait for the peak.
Here it is in detail, exactly as I do it in my kitchen:
- Grab a clean jar and your scale. I keep two Weck jars in rotation — one always clean, because I am not a person who washes jars promptly. Set the jar on the scale and zero it out.
- Add 30 grams of mature starter. Scoop it in with a spoon or pour it straight from the old jar. Precision matters less than consistency; being within a few grams is fine.
- Add 30 grams of flour. I use unbleached all-purpose — King Arthur flour most weeks, Bob’s Red Mill when it’s on sale. A spoonful of whole wheat or rye mixed in gives the microbes extra nutrients, which is nice if your starter seems sluggish.
- Add 30 grams of room-temperature water. Filtered is ideal if your tap water is heavily chlorinated, but honestly, my Portland tap water has never caused a problem. Aim for roughly 75°F — comfortable to the touch, not warm.
- Stir, mark, cover. Stir until there are no dry pockets. Mark the level with a rubber band so you can see the rise. Cover loosely — a lid set ajar, not screwed tight. The culture needs to breathe out CO2.
- Wait for the peak. In my kitchen at 68–70°F, a 1:1:1 feed peaks in about 6 hours. Watch for the dome flattening, the surface turning bubbly and slightly concave. That’s when it’s strongest — use it or feed it again.
That 30/30/30 example is my everyday feed. If I’m baking the next morning and need more starter, I scale up: keep 25g, feed 50g flour and 50g water (a 1:2:2). The bigger meal takes longer to peak — about 8–10 hours — which times perfectly with an overnight rise. I break down all the ratios in my feeding ratio guide.
Why You Have to Discard
You discard before feeding because without it, the starter grows exponentially and you’d need ever-larger amounts of flour to keep the ratio balanced. Removing most of the old culture keeps the feeding ratio consistent and prevents acidity from building up.
Here’s the math that finally convinced me. Skip the discard and feed 1:1:1: 100 grams becomes 300 after one feed, 900 after the next. Within a week you’d be feeding it a whole bag of flour. Hence the title of this post. Discarding feels wasteful until you do the arithmetic — then it feels like the only sane option.
The discard isn’t waste, either. It’s the same fermented flour you’d throw out, and it goes beautifully into pancakes, crackers, and flatbreads. I keep a running jar in the fridge for exactly this purpose. My sourdough discard hub, and the pillar guide to recipes using sourdough starter has the full recipe list.
One more reason to discard: acid balance. As Lactobacillus bacteria work, they produce acetic and lactic acid. A little acid is flavor. Too much — from a starter that’s been fed without discarding for weeks — and the gluten structure weakens, the yeast struggles, and your bread tastes like vinegar with regret. Regular discarding keeps the ecosystem balanced.
How to Know When It’s Time to Feed
Feed your starter when it has peaked and just started to fall — the dome flattens, the surface shows bubbles popping, and it may have slid down a centimeter from its high mark. For a room-temperature starter, that’s usually 8–12 hours after the last feed; refrigerated starters need it weekly.
The rubber band trick is your best friend here. Mark the level right after feeding. When the starter has clearly risen and the top has gone from domed to flat or slightly sunken, it’s hungry. Feed it now and it’ll peak again, stronger.
Don’t feed just because it doubled, though. A starter can double while still climbing. Wait for the peak — the flattening dome — because that’s when the yeast population is at its maximum and the acids haven’t yet taken over. This is the single biggest timing upgrade most beginners can make, and it costs nothing. My feeding schedule guide for the weekly routine.
Feed amounts by starter size
| Seed starter kept | Flour added | Water added | Ratio | Total after feed | Best for |
|---|---|---|---|---|---|
| 20 g | 20 g | 20 g | 1:1:1 | 60 g | Minimal waste, weekly bakers |
| 30 g | 30 g | 30 g | 1:1:1 | 90 g | Everyday maintenance |
| 50 g | 50 g | 50 g | 1:1:1 | 150 g | Frequent bakers |
| 25 g | 50 g | 50 g | 1:2:2 | 125 g | Building for a bake day |
| 20 g | 100 g | 100 g | 1:5:5 | 220 g | Warm kitchens, long intervals |
Feeding Mistakes That Stall a Starter
The most common feeding mistakes are using volume instead of weight, feeding on a clock instead of by the peak, skipping the discard, using water that’s too hot or too cold, and switching flours every feed.
Volume instead of weight. A cup of flour can weigh anywhere from 120 to 160 grams depending on how you scoop. That inconsistency compounds hydration percentage feed after feed. A $15 kitchen scale fixed this for me overnight.
Feeding by the clock. “Feed every 12 hours” is fine as a starting point, but your kitchen isn’t a laboratory. In summer my starter peaks in 5 hours; in winter it takes 10. Watch the starter, not the clock.
Skipping the discard. Covered above — the jar grows, the acid builds, and the yeast suffers. I did this for a month with Bubbles and wondered why my loaves tasted like battery acid.
Extreme water temperatures. Hot water can kill the microbes outright. Ice-cold water just slows everything to a crawl. Room temperature — comfortable on your wrist — is the target.
Switching flours constantly. Whole wheat, rye, and all-purpose have different protein content and mineral levels, and your culture adapts to its diet. Changing flour every feed keeps it in perpetual adjustment mode. Pick one for maintenance and stick with it; use the fancy stuff for the levain you build for baking.
What Happens If You Miss a Feed?
If you miss a single feeding, nothing bad happens — just feed at the next opportunity, possibly at a slightly higher ratio to dilute accumulated acids. Starters are resilient; a week of neglect on the counter is recoverable, and a month in the fridge usually is too.
This is the question I get most in workshops, usually whispered like a confession. Last spring a woman told me she’d abandoned her starter for ten days during a family emergency and was sure she’d killed it. We fed it twice at 1:5:5 and by day three it was doubling like nothing had happened. These cultures survived the Oregon Trail in covered wagons. Your long weekend won’t finish them.
Missing one feed means the culture sits past peak for a while, builds up some extra acid, and develops that dark liquid (hooch) on top. The fix scales with the neglect:
- 12–24 hours late: feed normally at 1:1:1. It’ll bounce back within one cycle. Don’t double-feed to “make up” for it — that’s like eating two dinners because you skipped lunch.
- 24–48 hours late: pour off any hooch, then feed at 1:2:2. The bigger ratio dilutes the accumulated acids. Expect the next peak to be a little sluggish.
- 3–7 days late on the counter: treat it like a mini-revival — discard hard (keep 20g), feed 1:5:5 twice daily for two days. It should be doubling reliably again. If it came from the fridge, see my revival protocol.
The pattern to notice: the fix is always food, never drama. Starters evolved as some of the toughest microbial communities on earth — they can handle your vacation. One habit that prevents most missed feeds: tie feeding to an existing routine. Mine is morning coffee: kettle on, starter fed, day begins. The feeding schedule guide has calendar versions if you want something more structured.
FAQ
How much starter do I discard each time I feed?
Discard all but the seed amount you want to keep — typically 20 to 50 grams. So if your jar holds 150g and you’re keeping 30g, discard 120g. That discard goes in the fridge jar for pancakes, not the trash.
Can I feed my starter without discarding?
Occasionally, yes — when you need to build up volume for a big bake day, feed without discarding to multiply the culture. Just don’t make it a habit, or the acid load climbs and the jar overflows.
What flour is best for feeding a sourdough starter?
Unbleached all-purpose flour works for everyday maintenance — King Arthur or Bob’s Red Mill are both reliable. Adding a spoonful of whole wheat or rye gives extra nutrients if your starter seems sluggish.
Should I stir the hooch back in or pour it off?
Hooch — that dark liquid on top — is alcohol, a byproduct of fermentation and a sign your starter is hungry. For a mild flavor, pour it off; for a tangier loaf, stir it in. Either way, feed right after.
How long after feeding is sourdough starter ready to bake with?
When it peaks — typically 4 to 8 hours after a 1:1:1 feed at room temperature, longer in a cool kitchen. Look for the domed-then-flattened top and a surface full of bubbles, then mix your dough and start bulk fermentation.
Can I feed my starter twice a day?
Yes, and vigorous starters in warm kitchens often need it. Maurizio Leo of The Perfect Loaf feeds his starter twice daily at room temperature. Just keep the ratio consistent and watch the peak, not the clock.
Leave a Reply