Pre-ferments Explained: Poolish, Biga, and More

A pre-ferment gives part of a bread formula a head start. Mix and ferment that portion, then combine it with the remaining ingredients to make the final dough. Many recipes schedule the build overnight, but 12–16 hours is a common example, not part of the definition.

This separates some of the fermentation from the final dough’s production schedule. It can be useful when you want a ripe build ready for the next morning. Straight dough can also develop good flavor, including through a long, cool fermentation; a pre-ferment is one approach to organizing the process.

The Three Common Yeasted Pre-ferments

Poolish

A poolish normally contains equal weights of flour and water: 100% hydration. It uses commercial yeast and usually no salt. A ripe poolish is loose and well aerated. For a working method and readiness guidance, see how to make a poolish.

Poolish is common in baguettes and rustic wheat breads. It can contribute extensibility, but it does not single-handedly determine how open the finished crumb becomes. Final hydration, flour, mixing, fermentation and handling still matter. King Arthur’s preferment guide treats these bread-and-preferment pairings as useful starting points, rather than rules.

Watch for the activity and expansion described in your recipe. A bubbly surface and signs that the build has reached its rise are useful; substantial collapse and a high-water mark suggest it is past its best stage. A slightly late poolish does not automatically condemn the final loaf to flatness or excessive sourness. Its condition, amount in the dough and the rest of the formula affect the result.

Biga

Biga is an Italian preferment term often used for a stiff yeasted build. Its hydration is not fixed at 60%. Jeffrey Hamelman describes stiff versions at 50–60% and also notes wetter uses of the term in the publisher’s excerpt from Bread. Read the actual formula rather than assuming that the name specifies the water quantity.

A firm biga can be easier to divide into pieces than a liquid poolish, but it must be incorporated thoroughly in the final mix. Its hydration does not mean the finished bread must be tight-crumbed: King Arthur’s professional ciabatta uses a 60% hydration biga in a 76% hydration final formula. Those are two different flour-and-water calculations.

Biga is common in Italian breads, including ciabatta. Both biga and poolish are also used in pizza; see how they are adapted for pizza dough. Choose the build that belongs to the recipe and schedule you want to follow.

Pate Fermentee

Pâte fermentée means fermented dough, often called old dough. It can be a piece reserved from a previous batch or a small dough mixed specifically for the next bake. Unlike a conventional poolish or biga, it includes salt.

Its hydration, yeast and salt follow the dough formula. A lean dough at 65% hydration and 2% salt is one possibility, not the definition. Salt affects fermentation, but does not make old dough immune to overripening.

This method is convenient for regular baking when a compatible batch can supply the next one. Plan the reserved quantity so the first batch still yields the loaves you intend. Keep track of its flour, water and salt; adding old dough on top of a complete formula changes the formula.

Use a recipe written for old dough and follow its refrigeration schedule. A portion of sweet, buttery or egg-rich dough is not interchangeable with a lean flour-water-salt dough. It brings its other ingredients, allergens and storage needs into the next batch. Do not apply a lean preferment’s overnight room-temperature schedule to arbitrary leftovers.

Comparing Them in Practice

Yeast Dose, Temperature and Ripeness Belong Together

A small amount of yeast over a longer period is different from a larger dose over a short period. Warmer conditions usually advance the build faster. That is why a yeast percentage without the intended temperature, duration and yeast type is incomplete advice.

Fresh compressed yeast and instant dry yeast are not gram-for-gram equivalents. Hamelman’s published preferment discussion gives its professional yeast percentages as fresh yeast and treats instant yeast separately for the home formulas. Do not copy a fresh-yeast percentage into an instant-yeast build unchanged.

Weigh small amounts with a suitable scale when the recipe gives gram quantities. If it gives a small spoon measure, follow that recipe’s yeast product and schedule. Record actual maturity so you can adjust the next batch when your room is warmer or cooler.

Cooling a build slows its progress; it does not rewind fermentation already completed. Nor does freezing turn every preferment into an indefinitely dependable leavener. Freezing is possible for some doughs, but yeast performance can decline. A thawed portion requires planning and assessment, not an assumption of instant readiness or unchanged strength months later.

What Pre-fermentation Changes

Flavor: Fermentation changes the mixture of aroma and taste compounds. These reactions also occur in straight dough; they do not first appear only after an overnight build. Baking then changes that mixture further. An original dough-metabolite study found that changing yeast quantity and fermentation duration affected different compounds differently. More time is not a guarantee of more of every desirable flavor.

Handling: A ripe pre-ferment can alter extensibility and strength. More extensibility means the dough stretches more readily; it is not synonymous with stronger gluten. Excessively mature dough can lose useful structure, so more pre-fermentation is not always better.

Keeping quality: Some fermentation processes improve freshness or delay mold, but those are different outcomes. Research on selected sourdough cultures and organic acids found antifungal effects under its test conditions. It does not establish that every poolish loaf lasts four or five days or every sourdough loaf five or six.

Ingredients, baking, cooling, contamination and storage all affect how long bread keeps. Use the bread storage guide for practical handling, and freeze bread you will not use promptly. If bread becomes moldy, USDA advises discarding it, rather than trimming off the visible patch.

Sourdough Levains

A levain is a sourdough build prepared for a dough, using an established starter culture with yeasts and bacteria. The starter can be maintained for future bakes while the levain is used in the current one. The terms sometimes overlap; a suitably ripe starter can supply the recipe directly when its composition and quantity match.

Levains can be liquid or stiff. Choose hydration, flour and seed quantity for the recipe and schedule, rather than treating every levain as a fixed overnight build. Maurizio Leo’s beginner formula gives an example of a build taking about five to six hours under its stated conditions.

Hydration and temperature influence fermentation, but “wet equals lactic” and “stiff equals acetic” are too simple as predictions of taste. The organisms present, flour, feeding schedule and maturity also matter. An original study of 500 sourdough starters documents substantial variation in their microbial communities and functions.

Judge maturity through the recipe’s expansion and activity cues. Floating in water is not proof of peak readiness: King Arthur’s comparison found that immature starter could float. The beginner sourdough guide explains the wider process.

Hybrid Doughs

A recipe can combine a sourdough levain with commercial yeast, including a separate poolish. This gives the baker another way to manage flavor and timing. It does not imply that sourdough alone is inherently too acidic for baguettes or too weak for enriched dough.

Use a complete hybrid formula before experimenting with the balance. Adding a second build changes both ingredient accounting and fermentation; it is not just an extra flavor ingredient.

The Detmolder Three-Stage Rye Method

Multi-stage rye sourdough methods build a culture through successive additions of flour and water. The three stages are commonly called freshening sour (Anfrischsauer), basic sour (Grundsauer) and full sour (Vollsauer).

The IREKS technical guide explains how temperature, dough yield, maturity and stage quantities work together, and describes more than one schedule. A list of three times and hydrations is not enough to reproduce the method: the amount carried forward and each addition are essential.

This is an established way to coordinate rye acidification and leavening, not an objectively superior flavor ranking for every rye bread. Follow a complete formula rather than assigning each stage a single acid or flavor outcome.

Long Fermentation Without a Separate Build

A straight dough can undergo a long bulk fermentation, including a controlled cold schedule. Pointage en bac refers to bulk fermentation in a container; it does not inherently mean a particular refrigerator temperature or a guaranteed non-sour flavor.

A dough fermented as one batch has different practical demands from a separate pre-ferment. Compare schedules that use the flour, yeast quantity and cooling conditions you can reproduce. Do not assume that an 8–10°C bakery holding schedule is interchangeable with a normal home refrigerator, or apply a lean-dough schedule to a perishable enriched mixture.

Count Flour and Water Once

Prefermented flour percentage, or PFF, is the flour in the ripe build divided by the total flour in the dough, multiplied by 100. It is different from the weight of the entire build expressed as a percentage of flour.

For an accounting example, suppose a formula contains 500g total flour and 350g water. Putting 100g flour and 100g water into a poolish means:

• The poolish contains 20% of the formula’s flour.
• Its flour-and-water mass is 200g, equivalent to 40% of total flour weight.
• The final mix needs the remaining 400g flour and 250g water, plus the formula’s other ingredients.
• Total dough hydration stays at 70%.

This illustrates arithmetic, not a complete recipe: yeast, salt, ripeness and the remaining method still need specification. For levain, include flour and water carried in with the seed starter when doing a full mass balance. For old dough, also subtract its salt and account for any other ingredients. Check whether a recipe’s displayed total already includes those contributions before adding them again.

The baker’s percentages guide explains these calculations. The bulk fermentation guide covers the subsequent rise, and the desired dough temperature guide explains why a build’s actual temperature matters when choosing mixing-water temperature.