Sourdough Starter Guide: Ratios, Feeding & Maintenance

A sourdough starter is just flour and water hosting wild yeast and bacteria, but it behaves like a pet. It needs a schedule, a ratio, and a bit of understanding. This guide covers the feeding math, the schedules, and how to keep a starter healthy for years. For the grams at any ratio, use the starter feeding calculator.

What the feeding ratio means

Every feeding is written as three numbers: starter : flour : water, measured by weight.

• 1:1:1: equal parts. The standard maintenance feed. Fast, predictable.
• 1:2:2: one part starter, two parts flour, two parts water. A gentler feed for every-other-day schedules.
• 1:5:5: one part starter, five parts flour, five parts water. A large feed that takes longer to peak, ideal for a fridge schedule or a pre-bake strength build.

Higher ratios = more food per microbe = slower fermentation and a milder, less acidic starter. Lower ratios = faster, more sour, and needier. There is no “correct” ratio; there is only the ratio that fits your schedule.

The feeding math

At 1:2:2 with 50 g of starter, you add:

• Flour = 50 g × 2 = 100 g
• Water = 50 g × 2 = 100 g
• Total after feed = 50 + 100 + 100 = 250 g

At 1:1:1 with 50 g of starter: 50 g flour, 50 g water, 150 g total. The pattern is trivial once you see it, but if you keep a 40 g starter or want a 300 g jar, the feeding calculator saves you the arithmetic at 7 am.

Daily maintenance (room temperature)

• Keep 25–50 g of starter in a jar.
• Every 24 hours: discard everything except the keep amount, then feed at 1:1:1.
• Keep the jar loosely covered (the lid sits on top, not screwed shut) so gases escape.
• Use the discard for crackers, pancakes, or anything that asks for buttermilk.

Weekly maintenance (fridge)

• Feed at 1:5:5, wait 1–2 hours at room temperature, then refrigerate.
• Feed once a week. If you go two weeks, pour off the hooch (the dark liquid on top), stir, and feed.
• Before baking: take the starter out, feed at 1:2:2, and wait for it to double (4–8 hours at room temperature); that is your levain.

Reviving a dormant starter

A starter that has been in the fridge for months is not dead; it is hibernating. The revival schedule:

1. Pour off the hooch. Stir the starter well.
2. Discard down to 25–50 g and feed at 1:1:1.
3. Leave at room temperature. Feed again after 12–24 hours.
4. Repeat daily. The starter is ready when it reliably doubles within 6–8 hours after a feed, usually 2–4 days.

Signs of actual trouble: pink or orange streaks (discard and start over), a foul rotting smell (different from the pleasant sour/alcoholic tang), or no activity after a week of feeds.

Starter hydration: the second dial

Your starter has its own hydration, usually 100% (equal flour and water), sometimes 200% (liquid). This matters for two reasons:

1. Feeding math. A 200%-hydrated starter at “1:2:2” means something different than a 100% one. Keep your ratios and your starter hydration consistent.
2. Dough hydration. The starter carries hidden flour and water into your dough. A 100 g, 100%-hydrated starter adds 50 g flour and 50 g water to your totals. Recipes that ignore this are wrong by 2–5 hydration points; use the hydration calculator to get the true number.

The keep-it-simple rules

• Small jar, small discard, consistent ratio.
• Room temperature = daily feed. Fridge = weekly feed.
• Hooch means hungry, not dead.
• The starter doubles, you bake; it doesn’t double, you wait.
• Keep the lid loose and the jar clean.

When the bake itself misbehaves (dense loaves, gummy crumbs, no oven spring), the answers are usually in the troubleshooting FAQ.