The Library / Myths, tested
“It has to double before you can use it”
Doubling is a useful sign for a liquid wheat starter. For others it's the wrong test.
Why
How high a starter climbs depends on how much gluten it has to hold the gas and how thick it is. A stiff starter barely moves but swells and domes. A rye starter has little gluten, so it rises less and then cracks. A very liquid one can triple. All of them can be at their best when they look quite different from each other.
Further down
Better signs that travel across starters: a domed top that's just starting to flatten, bubbles through the whole jar and not only on the surface, a smell that's ripe and a little sharp, and timing that matches its usual rhythm. The app's peak prediction is built on that rhythm.
Updated 7 October 2026