Feeding Your Starter: Ratios, Timing, and the Float Test

Once your starter is alive, feeding becomes a rhythm rather than a chore. But the details — how much to feed, how often, and how to tell when it is ready — decide whether your bread rises like a dream or sits flat. Let us decode the three levers you control: ratio, timing, and temperature.

Reading a Feeding Ratio

A feeding ratio is written as three numbers: starter, flour, water. A 1:1:1 feeding means equal parts of each — take 50 grams of starter, add 50 grams flour and 50 grams water. This is a small, fast feed that peaks quickly, ideal when you bake frequently and keep your starter on the counter.

A larger ratio like 1:5:5 means one part starter to five parts flour and five parts water. There is far more fresh food relative to existing culture, so it ferments slower and peaks later. Bigger ratios are your friend when you want to feed once and walk away for the day, or before an overnight build.

Why Discard at All

Every feed usually starts by discarding most of the starter. This is not waste — it is population control. If you only ever added flour and water without removing any, the volume would balloon and the acidity would climb until the yeast could no longer thrive. Discarding keeps the culture young, vigorous, and manageable. Save that discard for pancakes and crackers rather than binning it.

Timing: Chasing the Peak

A starter follows a predictable arc after feeding. It rises, domes, reaches a peak where it has roughly doubled, then deflates as the food runs out. You want to use it at or just before that peak, when it is at maximum strength.

The peak might arrive in four hours or twelve, depending mostly on temperature and ratio. The best thing you can do is learn your starter. Mark the jar with a rubber band at feeding time and watch how long it takes to double.

Temperature Changes Everything

Warmth accelerates fermentation; cold slows it to a crawl. A starter at 26°C (79°F) may peak in four to five hours, while the same starter at 18°C (65°F) could take twice as long. This is a tool, not a problem. Use a bigger ratio or a cooler spot to stretch timing to fit your schedule, or a warm oven with the light on to speed things up.

The Float Test, Honestly

The float test — dropping a spoonful of starter in water to see if it floats — is a useful quick check, not gospel. A floating starter is well aerated and usually ready. But a very wet or very stiff starter can fool the test in either direction. Treat the float test as one data point alongside the two that matter more: visible doming and a clean, tangy aroma.

Building a Feeding Habit

If you bake weekly, keep a small starter in the fridge and feed it the day before you bake. If you bake most days, a counter starter fed on a consistent schedule will reward you with predictable, powerful rises. Either way, consistency beats precision. A starter fed roughly the same way at roughly the same time becomes astonishingly reliable — and reliability is what turns baking from a gamble into a craft.

Storing a Starter You Are Not Using

Life happens, and sometimes you will not bake for weeks. A sourdough starter is remarkably forgiving. Feed it, let it start to rise, then park it in the fridge with the lid snug. The cold slows the microbes to a near standstill, and a healthy starter can sit for two to three weeks between feedings without complaint. To wake it up, pull it out, discard most of it, and feed it on the counter. It may take two or three feedings over a day or two to return to full strength — do not rush it back into a loaf while it is still groggy. For longer breaks, dry a thin layer of starter on parchment, crumble it into flakes, and store it in a jar almost indefinitely. A pinch of those flakes, fed and coaxed, will rebuild the whole culture.