Tell me how much fed starter you need and the ratio you feed at, and I'll tell you exactly how much old starter, flour, and water to mix. No waste, no over-thinking it.
| Old starter to keep | — |
|---|---|
| Flour to add | — |
| Water to add | — |
A higher ratio (more flour and water per part of starter) feeds your starter more and takes longer to peak — handy when you want to feed at night and bake in the morning.
I'll send you my simple feeding rhythm and the little rescue tricks for when it looks sad. We've all been there.
A sourdough starter is a living thing, and like anything living, it needs to be fed. When I first kept a starter going, the part that confused me most wasn't whether to feed it, it was how much, and how often, and what all those ratios people throw around actually meant. So I built this sourdough starter calculator to take the guesswork out of feeding. You tell it your ratio and how much starter you want, and it tells you exactly how much starter, flour, and water to combine.
At its heart, feeding is simple. You take a little of your existing starter, throw most of it away or set it aside (that's the discard), and mix what's left with fresh flour and water. That fresh food is what keeps the wild yeast and bacteria alive and active.
You'll see feeding ratios written as three numbers, like 1:1:1 or 1:5:5. Those numbers are, in order, the parts of existing starter, then flour, then water, all by weight.
Notice the flour and water match each other in these examples, which keeps the starter at 100% hydration, the standard most recipes assume. The first number, the amount of old starter, is the lever that changes how the whole thing behaves.
Here's the part that made starter care finally make sense to me. The more old starter you keep relative to the fresh food, the faster it peaks, because there's a bigger population of yeast already there to eat the new flour. A 1:1:1 feed has lots of active starter and not much food, so it rises and peaks quickly, often in just a few hours in a warm kitchen.
A 1:5:5 feed has a tiny bit of starter and a big meal in front of it. It takes much longer to peak because that small population has to multiply before it works through all that flour. That's not a bad thing, it's a tool.
Once I understood this, I stopped fighting my schedule and started feeding to match it. The ratio is how you line up "peak" with "when I actually want to bake."
It depends entirely on where you keep it. A starter living on the counter at room temperature is active and hungry, so it usually wants feeding once or twice a day. If you bake often, that's the rhythm to keep.
If you don't bake every day (and most of us don't), keep your starter in the fridge. The cold slows everything down, so a fridge starter only needs feeding about once a week. When you want to bake, pull it out, give it a feed or two at room temperature over a day to wake it back up, and it'll be lively again. I keep mine in the fridge during busy weeks without any drama.
Every time you feed, you remove some starter first so the jar doesn't overflow and so the fresh food isn't outnumbered. That removed portion is the discard. You don't have to waste it. Discard is wonderful in pancakes, crackers, waffles, and quick breads. It won't make those things rise much (it's not at its peak), but it adds a gentle tang and uses up what would otherwise go in the bin. I hate wasting food, so finding uses for discard felt like a small win every week.
A starter is forgiving. Miss a feeding and it won't die, it'll just get hungry, maybe form a dark liquid on top (that's called hooch, just stir it in or pour it off) and smell sharp. Feed it again and it bounces back. The main rules: keep it warm enough to be active when you're using it, cold when you're storing it, feed it fresh flour and water on a rhythm that suits your baking, and don't panic over a missed day.
Use the calculator to nail your exact amounts for any ratio, then go bake something. You'll find my sourdough and the rest of what comes out of my kitchen in my recipes, and if you're dialing in a loaf, my hydration calculator and the rest of my other free tools pair nicely with this one. All free, no sign-up.
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