Starter Feeding Ratios, from 1:1:1 to 1:5:5

A sourdough feeding ratio is a recipe for the jar, written as three numbers: starter : water : flour, by weight. The first number is the ripe starter you keep. The second is the water you add. The third is the flour you add. A 1:2:2 feeding means each gram of starter is joined by two grams of water and two grams of flour.

The sourdough calculator on this site turns that ratio into amounts. This page is about choosing the ratio.

Read the numbers in order

Always read the ratio as starter, then water, then flour. People sometimes flip the last two, or treat the first number as flour. If your results look twice as large or twice as small as you expected, check the order before you blame the scale.

The numbers are parts, not percentages. 1:2:2 and 2:4:4 are the same relationship. 1:1:1 is equal parts of each. A custom ratio such as 1:2:3 adds more flour than water, which builds a stiffer starter.

Because the parts are weights, 50 g of starter at 1:2:2 takes 100 g water and 100 g flour. 20 g of starter at 1:5:5 takes 100 g water and 100 g flour. The small starter in the second case is being asked to lift a much larger feeding.

What changes when the ratio gets larger

A tighter ratio, such as 1:1:1, keeps a lot of ripe starter in the jar relative to the new flour and water. The new mixture starts with a higher proportion of already-active culture. It will typically rise and smell mature sooner than a leaner feed of the same starter, in the same room, with the same flour.

A wider ratio, such as 1:5:5, dilutes that ripe starter in a larger meal of fresh flour and water. The culture usually takes longer to come back to a peak. Bakers often use a wide feeding when they want more ripe starter for a dough, or a milder jar than a tight feeding would produce in the same time window.

These are tendencies, not timers. Flour, temperature, and the health of the starter will move the clock more than the ratio alone. Do not treat a ratio as a promise that the starter will peak in a set number of hours.

Everyday choices

1:1:1. Useful when you are maintaining a small jar and want it ready again without a large buildup. It uses less flour. The tradeoff is that more of the previous feeding remains, so the jar can taste more acidic if it sits a long time after the peak.

1:2:2. A common all-purpose feeding: twice the starter’s weight in water and twice its weight in flour. For 50 g of starter, that is 100 g water and 100 g flour, and a 250 g jar afterward.

1:3:3 and 1:4:4. Middle steps when 1:2:2 is coming ready sooner than you need, or when you want more starter than a 1:2:2 of your usual leftover will make.

1:5:5. A larger buildup. Starting with 20 g of starter, you add 100 g water and 100 g flour and finish with 220 g. This turns a small leftover into enough starter for a dough, and it generally needs more time than 1:2:2 in the same conditions.

You can go wider still, or use an uneven ratio such as 1:2:3 if you want a slightly thicker starter.

Match the feeding to the amount you will use

Before you pick a ratio, decide how much ripe starter the dough needs, and how much you want to leave in the jar for next time. Work backwards.

If the dough needs 100 g of starter and you want 20 g left over, you need about 120 g ripe starter. A 1:2:2 feeding from 24 g of starter yields 120 g; a 1:5:5 from about 11 g also yields about 120 g, but usually takes longer to ripen. Make a little extra rather than scraping the jar bare.

Keep water and flour in the same unit

The ratio only works if starter, water, and flour are weighed in the same unit. Grams or ounces are fine; cups are not, because flour volume varies too much. If you change the flour, for example from white to whole-grain, the same ratio can still behave differently. Whole-grain feedings often move faster. That is a flour effect, not a failure of the ratio.

Put the ratio into the calculator

On the home page, enter the starter you will feed, choose a preset ratio or Custom, and read the flour and water to add. Then, when that starter goes into a dough, use the hydration panel so the new feeding is counted correctly. A starter you just built with equal weights of water and flour is a 100% hydration starter, even if the leftover you started from was stiffer, once the new flour and water dominate the jar.

For a worked 1:2:2 example and the default hydration numbers, see how to use this simple sourdough calculator. For scale and leftover habits, see using the calculator with your starter.