Sourdough Starter Guide: Ratios, Feeding & Maintenance

A sourdough starter is flour and water with wild yeast and bacteria living in it. It acts a bit like a pet. It needs a schedule, a feeding ratio, and a little understanding. This guide covers the math, the routines that actually work, and how to keep a starter healthy for years. For exact gram amounts at any ratio, use the starter feeding calculator.

What the feeding ratio means

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

• 1:1:1: equal parts. The standard daily feed. It peaks in 4 to 6 hours and is the easiest to remember.
• 1:2:2: one part starter with two parts flour and two parts water. A gentler feed that suits a fridge routine or a busy week.
• 1:5:5: one part starter with five parts flour and five parts water. A large feed that takes longer to peak and is good for a weekly fridge routine or a strength build before baking.

Higher ratios give the microbes more food, so fermentation is slower and the starter stays milder and less acidic. Lower ratios are faster, more sour, and need feeding more often. There is no single correct ratio, only the ratio that fits your schedule.

The feeding math

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

• Flour: 50 g times 2 = 100 g
• Water: 50 g times 2 = 100 g
• Total after feeding: 50 + 100 + 100 = 250 g

At 1:1:1 with 50 g of starter, that is 50 g flour and 50 g water, 150 g total. The pattern is simple once you see it. If you keep 40 g or want 300 g in the jar, the feeding calculator does the arithmetic for you.

Daily care at room temperature

• Keep 25 to 50 g of starter in a jar.
• Every 24 hours, discard everything except that keep amount, then feed at 1:1:1.
• Leave the lid sitting on the jar, not screwed tight, so gas can escape.
• Use the discard for crackers, pancakes, or anything that likes a bit of tang.

Weekly care in the fridge

• Feed at 1:5:5, leave the jar at room temperature for one to two hours, then refrigerate.
• Feed once a week. If you miss two weeks, pour off any dark liquid on top, stir, and feed.
• Before baking, take the starter out, feed at 1:2:2, and wait for it to double. That usually takes 4 to 8 hours at room temperature. That doubled starter is your levain.

Bringing a sleepy starter back

A starter that has sat in the fridge for months is not dead, it is sleeping. To wake it up:

1. Pour off any dark liquid. Stir the starter well.
2. Keep 25 to 50 g and feed at 1:1:1.
3. Leave it at room temperature. Feed again after 12 to 24 hours.
4. Repeat daily. It is ready when it reliably doubles within 6 to 8 hours after a feed, usually after two to four days.

Signs of real trouble: pink or orange streaks, a foul rotting smell that is very different from the usual sour or alcoholic tang, or no activity after a week of daily feeds. In those cases, discard and start fresh with a clean jar.

Starter hydration, the second thing to watch

Your starter has its own hydration. Most home starters are 100% hydration, meaning equal flour and water, and some are 200% liquid starters. This matters in two places:

1. Feeding math. A 200% starter at 1:2:2 is different from a 100% starter at 1:2:2. Pick a hydration and keep your ratios consistent.
2. Dough hydration. The starter carries flour and water into your dough. A 100 g starter at 100% hydration adds about 50 g flour and 50 g water. Recipes that ignore that are off by two to five points. Use the hydration calculator to get the true number, and compare levels on the hydration chart.

Simple rules that keep a starter happy

• Small jar, small discard, same ratio most days.
• Room temperature means feed daily. Fridge means feed weekly.
• Dark liquid on top means hungry, not dead.
• If it doubles, bake. If not, wait.
• Keep the lid loose and the jar clean.

If your bread is dense, gummy, or flat even though the starter looks good, the problem is usually fermentation or hydration. See the troubleshooting FAQ for practical fixes.