Pâte fermentée

Pâte fermentée is old dough used as a Preferment: a piece of already mixed bread dough, held and then returned to a new Mixing. Calvel treats it as one of the preferment methods of technical breadmaking ¹. Because it is leftover dough, it already contains Salt, and usually the yeast or leaven of the previous batch. That is the distinction.

It is not Poolish (a liquid flour-and-water yeast sponge) and not Levain (a build from sourdough starter). It is closer in stiffness to a dough than to a batter. Do not invent a hydration for it: it is the hydration of the bread it came from.

How to read it in baker's percent #

King Arthur Baking's preferment arithmetic still applies. As one line, old dough inflates the preferment percentage and makes water and salt look wrong. Split it into flour, water, salt, and yeast, add those weights into the new dough, and recompute overall baker's percent ². The flour that already fermented is Prefermented flour.

What to notice #

Ripe old dough is still extensible, not a gray, alcoholic paste. Salt in the piece means it ferments differently from a saltless sponge: slower, tighter gluten. Too much of it in the new mix and you taste yesterday's acid more than today's bread. Too little and you have only renamed a straight dough.

A stiff yeast sponge built on purpose, without that salt history, is the Biga family — a neighbor, not a synonym.