Caring for Your Starter

What this is about

Your starter is alive and needs fresh flour and water on a regular basis. If you feed it on a fixed pattern and recognize when it is ripe, it will be ready on baking day.

How to do it

You still need the jar with the rubber band, the scale, and the thermometer. Feed it with the flour you used to start it, and do not switch flours.

Feeding at room temperature: Take 20 g starter, add 20 g flour and 20 g water, and stir until smooth. This is the ratio 1 : 1 : 1, meaning equal parts starter, flour, and water. Discard the rest before you feed, and always weigh; never guess. Put the rubber band at the height of the mixture and rest the lid on loosely.
Wait for the peak: At 24 °C, it takes 4 to 6 hours until the starter stands at its highest. The cooler the room, the longer it takes: at 18 °C it is 8 to 12 hours. Measure the temperature at the jar before you decide a sluggish starter is weak.
Feed again only after the peak: If you discard and feed before then, you weaken it. At 24 °C this usually means once a day.
Fridge: If you don't bake every day, the starter belongs in the cold. Feed it as in step 1, let it sit for one to two hours, and put it in the fridge at 4 °C with the lid loose. Once a week, take it out, discard all but 20 g, feed it as in step 1, let it sit again for one to two hours, and put it back.
Refresh twice before baking day: You don't bake straight from the fridge; the dough would turn sluggish and the bread sour. The weekend plan: On Friday at 8:00, take the starter out and feed it 1 : 1 : 1 with 20 g, 20 g, and 20 g. On Friday at 20:00, feed it a second time, this time with 10 g starter, 50 g flour, and 50 g water. With more flour and water, it takes longer to reach its peak, so it is ripe by the next morning.
Saturday at 8:00: Your starter is now at its peak. You start the levain, the build made for this one dough: 20 g starter, 90 g flour, 90 g water. This is the start of baking day.

Ripeness curve of one feeding cycle — One feeding cycle at 24 °C: steep rise, peak, collapse. The band shows when you use it.

Starter in a straight canning jar at its peak — The rubber band sits at the height of the freshly fed mixture. Above it you see the domed top and the network of bubbles along the glass wall: this is what the peak looks like. AI-generated.

How you know it is right

The starter is ripe when the dome flattens, bubbles sit on the surface and along the glass wall, the mass is as airy as mousse, and it smells sour with a trace of sweetness. What matters is the combination of these signs, not the height above the rubber band. Right after feeding, it is dense, without bubbles, and sweetish: never use it at that point.

If the middle has sunk and streaks remain on the glass wall above the fill level, it is overripe. It still works, but the bread will be more sour; it is better to feed it once and wait for the next peak. If it smells of acetone or alcohol, or gray liquid sits on top, it is hungry: pour off the liquid and feed. Mold, meaning fuzzy spots or pink and orange films, means throw it out and start a new one. If it does not rise after the second feeding, put the jar somewhere warmer, at 24 °C, feed it once more, and move the baking day back by one day.

Rules to remember

Always weigh when you feed, and feed only after the peak.
You recognize ripeness by dome, bubbles, and smell, not by height.
In the fridge, feed it once a week; before baking day, refresh it twice, Friday at 8:00 and 20:00.

In the Pro edition: a backup copy, drying and freezing, feeding ratios and hydration compared, starter diagnosis, and how to rescue a neglected starter.