Preferments: Poolish, Biga and Pâte Fermentée

A preferment is a portion of a bread's flour, water and a little yeast mixed hours ahead and left to ferment before the final dough is made. That slow start builds flavor, improves the dough's strength and extensibility, and helps the finished loaf stay fresh longer. It is how many bakeries get complex, wheaty flavor in a same-day bread without sourdough.

The three most common commercial-yeast preferments differ mainly in hydration and form. A poolish is a wet batter, a biga is a stiff dough, and pâte fermentée is simply a piece of finished dough saved from an earlier batch. This guide covers how each is made, what it contributes, how to judge when it is ready, and how to work one into a recipe.

Poolish

Mix equal weights of flour and water with a very small amount of instant yeast, about 0.1 to 0.2% of the poolish flour weight for an overnight rest at room temperature. For 200 g flour and 200 g water, that is roughly a pinch, around 0.2 to 0.4 g. Cover and leave it at about 20 to 22°C (68 to 72°F) for 12 to 16 hours.

A ripe poolish is domed and covered with bubbles, smells sweet and slightly alcoholic, and has just begun to wrinkle or sink at the center. Use it then. If it has collapsed and smells sharply sour, it has gone past its peak and will weaken the dough.

• Common in baguettes, ciabatta and many French and Italian breads
• Gives extensibility: dough stretches easily and opens well in the oven
• Typically holds 20 to 40% of a recipe's total flour

Biga, the stiff preferment

A biga is a stiff preferment, usually 50 to 60% hydration, with a small amount of yeast. It is mixed into a firm, shaggy dough and left to ferment 12 to 16 hours at cool room temperature, or longer in the fridge. Because it is drier, fermentation is slower and the flavor stays milder and less acidic than a poolish.

Biga adds strength, which suits wet doughs such as ciabatta that need structure. It is traditional in many Italian breads. A ripe biga has roughly doubled, feels soft and domed, and shows a web of gluten strands when pulled apart.

Pâte fermentée

Pâte fermentée, sometimes called old dough, is a complete dough containing flour, water, salt and yeast. Bakers traditionally save a piece from one day's batch to add to the next. At home, you can mix a small dough the day before, let it rise for an hour, then refrigerate it overnight.

Because it contains salt, it ferments more slowly and contributes strength and flavor without making the dough slack. When you add it to the final dough, adjust the salt in the main mix so the total stays correct.

Adding a preferment to a recipe

Tear or spoon the ripe preferment into the bowl with the remaining water, then add the remaining flour, salt and yeast and mix as usual. Breaking it up in the water first helps it disperse evenly. The final dough needs less yeast because the preferment is already active; many recipes cut the final yeast by half or more.

To convert a straight dough, decide what share of the flour to preferment (20 to 30% is a good start), move that flour and the matching water into the preferment, and subtract both from the final dough. Keep the overall hydration and salt the same.

Timing and temperature

Temperature controls how fast a preferment ripens. A warm kitchen can push a poolish past its peak in 8 hours; a cool one may need 16. If your kitchen is warm, cut the yeast or chill the preferment for part of the time. If you need it sooner, use slightly more yeast and a warmer spot.

A preferment past peak is still usable in small amounts, but expect a weaker, stickier dough and a more sour taste. Planning the mix for the evening before a morning bake works for most schedules.

Common questions

Is a poolish the same as a sourdough starter?

No. A poolish uses commercial yeast and is made fresh for each batch. A sourdough starter is a maintained culture of wild yeast and bacteria that produces more acidity.

Can I refrigerate a ripe preferment?

Yes, briefly. Refrigerating a ripe poolish or biga for a few hours slows it down and can buy you time. Let it warm slightly before mixing so the dough is not too cold.

Which preferment should I start with?

A poolish is the most forgiving. It is easy to mix, easy to read when ripe and works in many lean breads, from baguettes to pizza.