Sourdough starter: make it, feed it, keep it healthy

Starter guides

Start at the top if you are making your first starter; jump to the problem if you have one. Each guide links the feeding calculator and the jar guide.

• What a starter isFlour, water, wild yeast and bacteria, and why it raises bread.
• Make a starter from scratchDay by day, with what each day looks like.
• Feeding and ratios1:1:1, 1:2:2, 1:5:5: what each ratio does to timing.
• When it is readyPeak, doubling, smell and the float test.
• Keeping it in the fridgeWeekly care and waking it up to bake.
• What is wrong with it?A few taps from what you see to what to do next.
• Not risingThe usual causes, from a cool kitchen to a missed peak.
• Reviving a neglected starterMissed feeds, sluggish rises and how to bring it back.
• Hooch: the liquid on topWhat it means and whether to pour it off.
• Mold: when to throw it outFuzz, pink streaks and the harmless look-alikes.
• Too sour, too weakHow to make a starter milder or stronger.
• Stiff vs liquid starter50% or 100% hydration, and how to switch.
• Less discard, smaller startersKeep 20 g and build only what you bake with.
• Drying, freezing and travelA backup in a jar, and how to bring it back.
• Starter, levain, poolish, bigaThe preferments, and which is which.
• Changing the flourRye, whole wheat or white, and switching over.
• Which waterTap, filtered, and the temperature that matters more.
• A starter someone gave youFirst steps in your kitchen.
• Jar and temperatureWhich jar, which lid, and where to keep it.

The routine in one paragraph

Keep a small amount of starter, say 20 to 50 g, in a clear jar. Feed it by stirring in fresh flour and water by weight, usually equal amounts (1:1:1), and discard the rest or use it. Watch it rise; when it has doubled and is domed and bubbly, it is ready to go into dough. If you will not bake for a few days, let it rise for an hour after feeding and put it in the fridge.

Temperature sets the pace

At 75 to 78°F (24 to 26°C) a 1:1:1 feed usually peaks in 4 to 8 hours; in a cool kitchen it can take most of a day. That one fact explains most "my starter is slow" questions. A warm spot, warmer water, or a jar warmer speeds it up; the fridge slows it almost to a stop.

Which flour

Whole wheat and rye flour carry more of the yeast, bacteria and nutrients a young starter needs, so they start faster. Once it is established, most bakers feed with bread flour or all-purpose, or a mix with some whole grain (10 to 20% is our starting point). Unbleached flour is the usual choice.