The signs, from most to least reliable
- It grows. Mark the level on the jar after feeding. A ready starter rises clearly, and in a warm kitchen it doubles within a few hours.
- It is full of bubbles. Look at the glass from the side. A ready starter has bubbles of different sizes all the way through, not only on top.
- It smells good. Pleasantly sour, yeasty or fruity. A sharp, stinging smell means hungry or in trouble.
- The dome. A firm starter shows a small dome at its peak. When the dome falls in, it is hungry.
- The float test. A spoonful that floats in water holds a lot of gas. It is a quick check, but not a guarantee.
What the float test can and cannot tell you
Floating usually means the starter is full of gas and active. But a spoonful can sink and still raise bread, for example when it was stirred and lost gas. And a very runny starter can float while it is not ready. Treat the float test as one clue and rely on growth and bubbles first.
Ready to bake is not the same as ready to feed. Use the starter when it is at or just before its peak, when it is full of gas. After the peak, when it sinks back, it is hungry. Feed it first.
Common mistakes
- Using the starter long after the peak, when it has already collapsed
- Judging by the clock and not by what the jar shows
- Using a young starter that does not reliably double yet
- Skipping the mark on the jar
The complete refresh plan, the dome test and the float test explained step by step are in the Starter Kit. The Starter Colleague tells you each day whether your starter is on track.
Get the Starter Kit — €16