How to Tell When It's Ready to Bake With
Okay. This is the lesson people keep asking me about early, and I keep telling them it's too soon to worry about it, and now here we are, so let's do it right.
Your starter can be alive and bubbly and still not ready to make bread with. Those are two different questions. "Is it alive" just means it's eating and growing. "Is it ready" means it's strong enough to lift a loaf of dough on its own, with no help from commercial yeast. That second one takes longer than people want it to.
Here's how I actually check mine, in order.
The float test (do this one first)
Take a small spoonful of starter right after you've fed it and it's peaked, meaning it's puffed up as high as it's going to go. Drop it into a glass of room-temperature water.
If it floats, you're in business. That means there's enough gas trapped in there to make it buoyant, which is basically the same thing that's going to happen in your dough.
If it sinks, it's not ready yet. Feed it again and check back at peak next time.
I'll be honest, the float test gets more credit than it deserves. I use it, but I don't treat it as gospel. I've had starter sink and still bake a decent loaf, and I've had it float and give me a sad one. It's a data point, not a verdict.
The rise-and-fall pattern
This is the one I trust more. Feed your starter, mark the level on the jar with a rubber band, and watch it over the next several hours.
You want to see it roughly double, or close to it, within somewhere around 4 to 8 hours depending on your kitchen temperature. Ours runs cooler than people expect because of the dry air pulling heat off surfaces, so don't panic if you're on the long end of that.
Then — and this part matters just as much as the doubling — watch what happens after it peaks. It should fall back down some. That fall tells you the yeast ran out of food and started to slow. A starter that's ready to bake with should show you both halves of that curve: up, then down a little. Not just up and stalled at the top for a day.
Smell and texture
By now you know what your starter smells like day to day. Ready-to-bake starter smells sharp, a little like yogurt or beer, definitely tangy, not the flat flour smell from early on and not sharp-nail-polish sharp either — that's a starter that's gone too long past peak and is hungry.
Texture-wise you want it airy all the way through, not just bubbles on top. Stir a spoon down into the jar. If it's full of little bubbles clear to the bottom, that's a strong culture. If it's dense at the bottom with a bubbly crust on top, it's not distributed the way you want and probably needs another feed or two before you trust it with a loaf.
Put it on a schedule, not a guess
My opinion, and I'll say it plainly: I'd rather you feed your starter on a schedule you'll actually stick to than chase perfect readiness every single time. Twice a day if you're baking often, once a day if you're not, same time each day if you can manage it. Consistency does more for a starter's strength than any one clever test does. I learned that one the hard way, wanting to bake constantly and feeding on no pattern at all, and the starter just never got as strong as it should have.
A caution on timing
Don't start your loaf's bulk ferment late at night thinking you'll just deal with it in the morning. Dough doesn't pause for your schedule, and an active starter especially won't.
I brought a loaf to a ward party once, actually got it right that time, good crust, decent crumb, and set it down on the food table feeling pretty proud of myself. Then I spent the whole rest of the night resetting folding chairs because somebody had to, and by the time I got back to the table, some kid had eaten half my loaf before I'd had a single slice. I still count that as a win. People eating your bread before you get any is a pretty good sign it turned out fine. But it also taught me something about timing — I'd built that loaf around when I thought I'd have a quiet minute to eat it, and there wasn't one. Dough and parties both run on their own clock. Plan around that, not around what you wish would happen.
Before next time
Start marking your jar with a rubber band at every feed for the next few days and take a quick photo when it peaks. You'll start to see your own starter's rhythm instead of guessing at somebody else's timeline.