How Sourdough Feeding Ratios Work
A feeding ratio is written as starter : flour : water. A 1:1:1 feed means for every gram of starter you keep, you add one gram of flour and one gram of water. So 50 grams of starter fed 1:1:1 gets 50 grams of flour and 50 grams of water, ending at 150 grams total. Bump it to 1:5:5 and that same 50 grams of starter takes 250 grams of flour and 250 grams of water, finishing at 550 grams. The bigger the flour and water numbers, the more you dilute the old, acidic starter with fresh food, which slows the rise and keeps the flavor milder.
flour = starter x ratio_part | water = flour x (hydration / 100) | total = starter + flour + water
Hydration Is Separate From the Ratio
Most starters run at 100% hydration, meaning equal flour and water by weight. That is the default here, so 1:2:2 gives you a balanced paste. If you keep a stiff starter at 60% hydration, the water drops to 60% of the flour weight, so 100 grams of flour pairs with just 60 grams of water. A stiffer starter peaks more slowly and tastes less sharp, which is why some bakers use it for sweet doughs and panettone.
Why the Ratio Changes Your Timeline
The amount of fresh flour controls how long the yeast and bacteria have to feast before they exhaust the sugars and collapse. A small 1:1:1 feed at 72F can peak in roughly 4 to 6 hours and then go flat and sour. A heavy 1:5:5 feed gives the same starting microbes far more to eat, so it climbs slowly and can take 10 to 14 hours to peak, staying mild the whole way. Temperature swings this hard: every drop of about 9F roughly doubles the time, which is why a 65F kitchen behaves nothing like an 80F one. Use the estimated peak time as a planning guide, but always confirm by eye, your starter should double or triple and dome before it sinks.
Frequently Asked Questions
What ratio should I feed my starter?
For a starter you bake with often, 1:1:1 or 1:2:2 keeps it strong and active on a daily rhythm. If you bake less or want a milder loaf, a larger feed like 1:4:4 or 1:5:5 buys you more time between feedings and produces a gentler, less sour flavor.
How much flour and water do I add to 50 grams of starter?
At 1:1:1 you add 50 grams of flour and 50 grams of water, ending at 150 grams total. At 1:2:2 it is 100 grams of each, and at 1:5:5 it is 250 grams of each. The flour amount always equals your starter weight times the ratio number, and at 100% hydration the water matches the flour.
Does a bigger feed make my starter less sour?
Yes. A larger feed dilutes the acid and bacteria already in the jar with a lot of fresh flour, so the starter has to multiply more before the pH drops. That extra runway means a milder, sweeter result, which is why bakers chasing a tangy loaf stick to small 1:1:1 feeds and let them sit longer.
Why does my peak time estimate change with temperature?
Fermentation is driven by enzyme and microbe activity that speeds up in heat and slows in cold. As a rule of thumb, every roughly 9 degrees Fahrenheit cooler doubles the time to peak. The calculator uses that doubling rule alongside your feed size, but your flour, starter age, and jar shape all matter, so treat the time as a starting estimate and watch the rise.
Practical Guide for Sourdough Starter Feeding Calculator
The discard step is where most ratio confusion starts. Before you feed, you scoop out and set aside most of your starter so you are only feeding a small amount, like the 50 grams in this calculator. Feeding the whole jar 1:1:1 would balloon it into a bucket within a few cycles, so keeping a small base and giving it a generous feed is how you maintain a lively starter without wasting flour by the bag.
Match the ratio to your schedule, not the other way around. If you feed in the morning and want to bake that evening, a 1:2:2 or 1:3:3 feed at room temperature lands the peak right when you need it. If you feed at night and bake the next afternoon, go bigger with 1:4:4 or 1:5:5 so it does not peak and collapse while you sleep. The estimated peak time here is meant to help you reverse-engineer the feed that finishes on your timeline.
Hydration is your texture and tang dial once the ratio is set. A 100% hydration starter is pourable, peaks faster, and tastes brighter. Drop to 60 to 70% and you get a stiff dough-like starter that rises more slowly, resists going sour, and stores longer in the fridge. Many bakers keep a 100% liquid starter for everyday loaves and a stiff one for enriched and sweet bakes, feeding each with the same ratio logic but a different water number.
Quick Checklist
- Weigh starter, flour, and water in grams with a scale, never by volume.
- Pick a ratio that peaks when you plan to bake, then confirm by the rise, not the clock.
- Use a bigger feed (1:4:4 or higher) before a fridge rest or to mellow the sourness.
- Mark the jar at feed time so you can see when it has doubled and domed at peak.