Levain
The portion built from a sourdough starter specifically for one bake, at a chosen hydration, flour and quantity — a stage in a method rather than a culture kept indefinitely.
Also called leaven (UK); build (TRADE); elaboration (TRADE)
In careful usage a levain is not the same thing as a starter, and the distinction is useful rather than pedantic. The starter is the population kept alive continuously; the levain is the quantity built from it for a particular loaf, often at a different hydration or with a different flour, timed so that it reaches peak when the dough needs it.
Separating the two solves a practical problem. A baker who mixes dough directly from the maintained starter has to keep that starter at the hydration, flour and volume the formula requires, which forces the maintenance schedule to serve the bake. Building a levain instead lets the starter be kept however suits the baker, and the levain be built to whatever the loaf needs. It also means the accumulated acidity of the maintained culture is diluted, which is why levain-built loaves are often milder than their starter suggests.
When to throw it away
A levain is built from a starter and used within hours, so it carries the same safety position as its parent culture and no additional one. If the starter it came from showed mould or unusual colour, the levain built from it must be discarded too — building from a compromised culture does not dilute the problem away.
What is living in it
Microbiology
The same population as the starter it was built from, at an earlier point in its fermentation and at a lower accumulated acidity. A levain is not a different culture; it is the same culture diluted and given fresh substrate.
Follows directly from what a levain is. No independent microbiological claim is made here beyond the parent culture’s.
RecordedFollows from evidence recorded elsewhere on BakeHQ
Hydration
Typical hydration
50–125% (typically 100%)
Chosen per bake rather than characteristic. A stiff levain is used where a milder, more acetic result is wanted; a slack one ferments faster.
RecordedEstablished practice, not a measured result
How it is kept
It is not maintained
A levain is built and used up. This is the practical difference from a starter: nothing is kept back from it, and no schedule attaches to it. Where a baker does keep a portion back, what they have kept is a starter.
A definitional statement about how the terms are used, not a claim about the world.
RecordedTrue by definition rather than by measurement
How to tell it is ready
These are observations, not a schedule. Time to peak depends on temperature, refreshment ratio and flour, and those interact — so the clock tells you roughly when to look, and the list below tells you what you are looking for.
- Sign 1
- Peaked and just beginning to recede — a levain used past its peak has already spent much of its gas-producing capacity.
- Sign 2
- Domed and visibly aerated through the body, not only at the surface.
- Sign 3
- Floats when a spoonful is dropped into water — a rough indicator that works for slack levains and misleads for stiff ones.
Why the terms are used loosely
In most English-language home baking the two words are used interchangeably, and BakeHQ records that as a fact about usage rather than correcting it. The alias on the starter record carries the note. Where the distinction matters — in a formula that specifies a levain build separately from the maintained culture — the difference is the one described above.
Related
Built and refreshed from
A levain is built from the starter plus fresh flour and water, at whatever hydration the loaf needs rather than whatever the maintained culture is kept at.