How often should you feed a sourdough starter

Counter or fridge: the two standard schedules

Almost every published schedule starts with one question: where does the jar live? South Dakota State University Extension puts it plainly. A starter stored at room temperature should be fed twice a day, and one stored in the refrigerator should be fed once a week. Clemson Cooperative Extension's Sourdough 101 guide gives the same split with a looser counter rhythm, recommending daily feeding for a starter kept at room temperature and weekly feeding for one in the refrigerator.

King Arthur Baking's sourdough maintenance guide lands in the same place: feed a room-temperature starter every 12 hours, twice a day, and a refrigerated starter at least once a week. The same guide says regular feeding can mean anything from twice a day to once a week, depending on your schedule and how often you bake.

Why temperature sets the pace

A starter is a small ecosystem of wild yeast and lactic acid bacteria, and both feed on the fresh flour you add. How fast they get through it depends on temperature. Colorado State University Extension says the microbes are most comfortable at a warm room temperature of around 70°F, that fermentation slows at colder temperatures, and that it can run too fast or even stop when it is too hot. The University of Illinois Extension suggests 70 to 82°F as the range that keeps the yeast active.

That is why a counter starter in a warm summer kitchen drifts toward the twice-a-day end, and why the cold of a refrigerator stretches the gap to a week. The microbes do not all prefer the same temperature, either. In a 1998 study in Applied and Environmental Microbiology, Michael Gänzle and colleagues at the University of Hohenheim found that the sourdough yeast Candida milleri grew best at about 27°C (81°F), a lower optimum than the Lactobacillus sanfranciscensis bacteria tested alongside it, both of which the authors describe as representative of sourdough.

The Illinois guide's advice for a sluggish starter that is not rising is to move it somewhere warmer or switch its flour to rye. The reverse holds too: a warm spot speeds everything up, including how soon the starter is hungry again.

Match the schedule to how often you bake

The University of Illinois Extension's Sourdough Bread 101 guide ties the schedule directly to baking frequency. If you bake every day or three to four times a week, feed the starter daily and keep it on the counter or somewhere warm. If you bake weekly, keep it in the refrigerator and take it out the day before you start a loaf. If you bake monthly, keep it refrigerated too, take it out the day before, and expect to feed it a couple of times 12 hours apart to get it going.

Colorado State's Sourdough Basics guide takes the fridge route as its default: keep the starter covered and refrigerated when not in use, and ideally feed and use it weekly. Its routine is to take the jar out, let it warm at room temperature for one to two hours, keep half a cup, feed it, and let it ferment at room temperature until it doubles, which it says can take anywhere from five to eight hours, before it goes back into the fridge.

Sources differ on that warming step. The Illinois guide says you do not need to bring a refrigerated starter to room temperature before feeding it, while Colorado State and the University of Alaska Fairbanks Cooperative Extension both have you let it warm first. Either way, the feeding is the part that counts.

What counts as a feeding

A feeding is more than adding flour. Clemson and Illinois both recommend a minimum ratio of 1:1:1, meaning equal weights of starter, flour and water. King Arthur's routine keeps 113 grams of starter and feeds it 113 grams each of water and flour. Colorado State explains why the rest gets removed: taking some starter out at each feeding stabilizes the population of microbes and makes sure there is enough food for the ones that remain.

The ratio also changes the timing. Illinois notes that feeding a higher ratio of flour and water slows the starter down, and suggests a 1:10:10 feeding the night before a morning bake, 10 grams of starter with 100 grams of flour and 100 grams of water, so that it peaks in the morning. A bigger meal buys more time before the starter is hungry again.

How to tell the schedule fits

A starter on a schedule that suits it rises and falls predictably. Clemson and Illinois both describe a healthy, active starter as one that doubles within four to six hours of a feeding, with bubbles throughout and a yeasty, pleasant smell. Illinois recommends using it at that peak, once it has at least doubled and before it falls back down.

A layer of liquid on top is the clearest sign that the gap between feedings has been long. Illinois explains that the yeast produce alcohol as well as carbon dioxide, and that it collects as a dark liquid at the top when the starter hasn't been fed in a while. Bakers call it hooch, and you can pour it off or stir it in. If you keep finding it on a counter starter, that is a hint to feed more often or to give a larger meal.

Common feeding schedule mistakes

Refrigerating a starter that is too young. South Dakota State advises against storing a starter in the refrigerator until its microbiome is established, which it puts at 7 to 10 days. Illinois has a brand-new starter fed daily, and twice daily from day four, before it is anywhere near the fridge.

Treating 12 hours as a deadline. King Arthur's guide points out that feeding every 12 hours does not mean a 4 p.m. feeding forces you up at 4 a.m.; 7 a.m. will be fine. A steady rhythm matters more than the exact minute.

Feeding without removing any. Skipping the discard makes the jar grow at every feeding and leaves less food for each microbe, which is exactly what Colorado State's removal step is meant to prevent.

Losing track of the day. With a weekly fridge rhythm, the hard part is often remembering when the last feeding was. Doughmi, a sourdough starter care app, keeps that for you: you pick a counter rhythm of every 12 hours, a fridge rhythm of every 7 days, or your own number of hours, and it reminds you one full rhythm after the feeding you last logged.

Frequently asked questions

Can I feed my sourdough starter once a day instead of twice?

Many bakers do. Clemson Cooperative Extension recommends daily feeding for a starter kept at room temperature, and a King Arthur Baking article says a counter starter is happiest fed once a day, while South Dakota State and King Arthur's maintenance guide say twice. A cooler kitchen or a larger feeding ratio slows the starter and makes once a day easier to sustain.

How long can a sourdough starter go without feeding in the fridge?

Weekly is the standard. King Arthur Baking says a refrigerated starter should be fed at least once a week, and that one forgotten for months can probably still be brought back, though it can take nearly as long as making a new starter. The University of Illinois Extension notes that the longer a starter goes without food, the more acidic it becomes.

Do I need to warm a refrigerated starter before feeding it?

Guides disagree. The University of Illinois Extension says it is not necessary. Colorado State University Extension lets the jar warm at room temperature for one to two hours first, and the University of Alaska Fairbanks Cooperative Extension also has you let it come to room temperature before adding flour and water.

Do I have to discard every time I feed?

For routine maintenance, yes. Colorado State University Extension calls regular removal an important step that stabilizes the population of microbes, and the University of Illinois Extension says it is necessary to keep the volume down. When you need extra starter for a recipe, King Arthur Baking suggests feeding without discarding until you have enough.