What feeding actually does.
Your sourdough starter is a living ecosystem of wild yeast and bacteria suspended in a flour-and-water medium. Feeding it means giving the population fresh food: more flour to consume, more water to live in. The microbes eat the flour, multiply, produce gas (which makes the starter rise) and acid (which gives sourdough its tang).
The ratio in a feed is shorthand for "how much old starter, how much fresh flour, how much fresh water." A 1:2:2 feed means for every 1 gram of existing starter, you add 2 grams of flour and 2 grams of water. Bigger ratios (more fresh food per old) mean a longer wait but a more vigorous peak. Smaller ratios mean a faster peak but less total growth.
Choosing the right ratio.
| Ratio | Best for | Peak at 22°C |
|---|---|---|
| 1:1:1 | Quick refresh, daily maintenance, small starter | 3–4 hours |
| 1:2:2 | Standard feed, predictable peak | 4–6 hours |
| 1:5:5 | Building before a bake, more dough | 6–8 hours |
| 1:10:10 | Long retard, fridge maintenance, vacation | 10–12 hours |
None of these is "right" or "wrong" — they're tools for different situations. A 1:1:1 is great when your starter is sluggish and needs a quick boost. A 1:5:5 is what you want the night before a bake so you have a fully active, peak starter ready in the morning. A 1:10:10 lets you feed Sunday and not feed again until Wednesday.
How temperature changes everything.
Yeast and bacteria are temperature-sensitive. The same 1:2:2 feed will peak in 4 hours in a warm summer kitchen at 26°C, but take 10 hours in a cool winter kitchen at 18°C. Bakers in cooler climates often switch to smaller ratios in winter and larger ratios in summer to keep their schedule consistent.
Bakebench's peak time estimates use a model that accounts for both ratio and temperature. Above 28°C, fermentation accelerates so much that timing windows shrink — you may need to set a timer rather than rely on visual cues. Below 18°C, fermentation slows enough that some bakers move their starter to a warmer spot (on top of the fridge, near a radiator) rather than wait.
Common starter feeding mistakes.
1. Feeding a sluggish starter the same way every time
If your starter peaks weakly or doubles slowly, a 1:1:1 feed for 2-3 cycles can wake it up faster than another 1:2:2. Match the feed to the starter's current vigor.
2. Using cold water
Cold water shocks the microbes. Use water at roughly room temperature, or slightly warm in a cool kitchen.
3. Mixing in a tall, narrow jar
You can't see the rise clearly. Use a wider container, or a glass jar with a rubber band marking the starting line.
4. Feeding at peak
If the starter is already at peak when you feed it, it has nothing left to grow on — the new food gets consumed slowly. Feed when the starter is past peak and starting to deflate, OR when it's at the bottom of its previous cycle.