How to Tell When Your Sourdough Starter Is at Peak and Ready to Bake

One of the most common questions in sourdough baking is this:How do you know when your starter is ready to use and truly at peak activity?
Using a starter too early often leads to weak rise.
Waiting too long can cause the dough to lose strength.
And this can happen even when the recipe itself is perfect.
In this article, we’ll go through the key signs of peak activity —
without complicated tests or unnecessary theory.

What does “starter at peak” mean?

When bakers say a sourdough starter is “at peak,” they mean it has reached its maximum activity after feeding.
At this point, the yeast is strong, the bacteria are balanced, and the starter can properly leaven bread dough.
Using a starter too early or too late is one of the most common reasons sourdough bread fails.

Why baking at peak activity matters

A starter at peak:
provides good oven spring
creates a lighter crumb
prevents dense or gummy bread
If the starter is past its peak, the dough may rise poorly or collapse during fermentation.

Once your sourdough starter is at peak activity, the next crucial step is knowing when the dough itself is ready for shaping.
Shaping too early or too late can ruin the structure, even with a strong starter.
👉 Here’s how to tell when dough is ready for shaping.

Visual signs your starter is ready

The easiest way to tell is by watching how your starter behaves.
A starter at peak:
has doubled or tripled in size
shows a domed or slightly flattened top
is full of bubbles throughout, not just on the surface
Once it starts to sink or leave streaks on the jar, it is already past peak.

The float test: should you trust it?

Many bakers use the float test, dropping a small piece of starter into water.
If it floats, they assume it is ready.
This test can work, but it is unreliable.
A starter may float and still be too weak or already declining.
Visual signs and timing are more reliable than the float test alone.

Timing: how long after feeding is peak?

There is no universal number of hours.
Peak time depends on:
flour type
hydration
room temperature
starter strength
For many starters, peak occurs between 3 and 6 hours after feeding at room temperature.
The key is not the clock, but consistent behavior.

Using a starter at peak activity is only one part of successful sourdough baking.
Many loaves fail not because of the starter itself, but due to fermentation, hydration, or timing mistakes.

👉 Here are the most common reasons sourdough bread fails — and how to fix them.

Common mistakes when using a starter

baking before the starter reaches peak
waiting too long and missing peak
using a weak or recently revived starter
relying only on the float test
These mistakes often lead to poor rise and dense crumb.

Final thoughts

A sourdough starter does not need to be perfect — it needs to be predictable.
Once you learn how your starter behaves and when it reaches peak activity, baking becomes much easier and more consistent.