A preferment is a portion of the dough made in advance. Modernist Pizza describes it as a head start: by the time you mix the final dough, the yeast in the preferment is already working, and its flour is already fully hydrated, which shortens mixing. The longer fermentation adds flavor from the acids it produces, and that acidity also helps the gluten develop.
The trade-off is planning. A preferment adds hours, sometimes days, to the schedule, depending on the type, how much yeast it gets and how warm it is.
The three kinds
| Preferment | Water to flour | Leavened by | Ready in | What it’s like |
|---|---|---|---|---|
| Poolish | Equal weights (100%) | A little commercial yeast | 12 to 16 hours at 70 to 75°F in Modernist Pizza’s recipes | Loose batter; mixes in easily |
| Biga | Stiffer; Forkish’s is 66% | A little commercial yeast | About 12 hours at 68°F in Forkish’s recipe | Firm dough; slower to mix in |
| Levain | Usually equal weights | Wild yeast and lactic acid bacteria | Hours after each feeding | A maintained culture; adds tang |
Modernist Pizza uses only poolish and levain in its recipes. It describes a biga as a stiffer poolish whose lower hydration means slower fermentation and a longer mix, and it doesn’t recommend stiff preferments because they’re hard to work into a dough. Ken Forkish, on the other hand, builds one of his favorite crusts on a biga: the 48- to 72-hour biga dough in The Elements of Pizza.
A poolish also tastes milder than a levain. Because it runs on commercial yeast, Modernist Pizza notes, it doesn’t have a levain’s tangy flavor.
Poolish: yeast, temperature and time
How fast a poolish ripens depends on how much yeast it gets and how warm it is, and Modernist Pizza adjusts the yeast to set the timing. The book’s own recipes give the poolish 12 to 16 hours at 70 to 75°F (21 to 24°C), and the authors note that an older poolish gives the dough more structure and fermentation flavor than a younger one.
The Pizza Planner uses its own adapted version: 0.1% instant yeast, as a share of the poolish’s own flour, and about 16 hours to ripen, with a window of 12 to 18. That’s the Planner’s route, not a universal dose. If you follow another published recipe, take its yeast, temperature and timing together.
These are tiny amounts. For 173 g of poolish flour, 0.1% is 0.17 g, which needs a scale that reads to 0.01 g.
Biga: Forkish’s version
Forkish’s biga is 250 g of flour, 165 g of water and 0.2 g of instant yeast, which is half of the recipe’s total flour. He mixes it in the evening; at 68°F (20°C) it should be ready in about 12 hours, when it has tripled and is visibly gassy, with what he calls “an alcoholic swoosh” of aroma when you open the container.
The next morning he mixes the remaining 250 g of flour with water and salt, then works the biga in. Because the two doughs have different consistencies, he warns it takes longer than usual to come together and suggests a 5- to 10-minute rest partway through. In total the dough has 70% water and 2.6% salt.
The Planner doesn’t model a biga. Its preferment option is a poolish (or a sourdough levain) at 100% hydration, so for a biga, follow Forkish’s recipe as written.
How to convert a straight dough
The principle: a preferment isn’t added to a recipe. It’s part of the recipe, fermented early. Total flour, total water and salt stay where they were; you move some of the flour and water into the preferment and take the same amounts out of the final mix.
The Pizza Planner states its preferment as a share of the recipe’s total flour. It supports 10 to 40%, at 100% hydration, and starts a poolish at 30%. Here is that conversion for four 12-inch Neapolitan-style pizzas for a home oven, the same dough as Formula 1 in our recipe by weight. The grams are the Planner’s own, rounded to whole grams above 10 g:
| Straight dough | With a 30% poolish | |
|---|---|---|
| Poolish: flour | — | 173 g |
| Poolish: water | — | 173 g |
| Poolish: instant yeast | — | 0.17 g |
| Final mix: flour | 577 g | 404 g |
| Final mix: water | 404 g | 231 g |
| Final mix: salt | 17 g | 17 g |
| Final mix: instant yeast | 1.7 g | 1.6 g |
| Total flour | 577 g | 577 g |
| Total water | 404 g (70%) | 404 g (70%) |
| Dough | 1,000 g | 1,000 g |
Step by step:
- Poolish flour: 30% of the total flour. 577 × 0.30 = 173 g.
- Poolish water: the same weight, because a poolish is 100% hydration. 173 g.
- Final mix: subtract them. 577 − 173 = 404 g of flour, and 404 − 173 = 231 g of water.
- Salt: work it out on the total flour, as before. 3% of 577 g is 17 g.
- Yeast: the Planner keeps the total at 0.3% of the flour (1.7 g) and subtracts the 0.17 g already in the poolish, leaving 1.6 g for the final mix.
Check the result by adding the flour and water back up: 173 + 404 = 577 g of flour, and 173 + 231 = 404 g of water, which is still 70%. If your totals change, something went in twice.
A ripe poolish gives the dough a head start, and Modernist Pizza notes that the more fermented flour a dough contains, the faster it moves. Go by how the dough looks at each stage rather than the clock.
Recipe: Neapolitan-style dough with poolish
Makes 4 dough balls of 250 g, for four 12-inch pizzas. Active time about 35 minutes. Elapsed time about 45 hours to the first pizza: about 16 for the poolish and 24 in the fridge. Bake 6 to 10 minutes per pizza.
- Make the poolish about 16 hours before you mix the dough: dissolve 0.17 g instant yeast in 173 g room-temperature water, add 173 g flour and stir until smooth. Cover airtight and leave at 70 to 75°F (21 to 24°C).
- Check the poolish: it is ready when it is domed and bubbly throughout and the bubbles start to burst when you gently move the container. If it has sunk back, see the notes on overripe poolish.
- Mix the dough: dissolve 17 g salt in 231 g water, then 1.6 g instant yeast. Add the poolish and loosen it in the water by hand, then add 404 g flour and mix until no dry flour is left. Rest 20 minutes, then knead for 30 seconds to a minute until smooth.
- First rise: cover and leave at room temperature for about 2 hours (1½ to 3), until the dough has expanded and feels aerated.
- Divide into four 250 g pieces and shape each gently into a ball.
- Refrigerate the covered balls at 34 to 41°F (1 to 5°C) for about 24 hours. Expect gradual expansion and small bubbles, not a doubling.
- Take the balls out about 2 hours (1½ to 3) before baking and keep them covered, until they are soft, airy and stretch without snapping back.
- Preheat a steel or stone at 500 to 550°F (260 to 288°C) for 45 to 60 minutes, then stretch each ball to 12 inches, top lightly and bake for 6 to 10 minutes, until the base is cooked through.
Is it ripe, or past it?
A ripe poolish. Modernist Pizza’s most important cue is visual: a ripe poolish has risen, is full of carbon dioxide bubbles, and its bubbles begin to rupture when you gently move the container. Its aroma is almost sweet, with what they describe as a hint of fresh milk. The Planner’s version of the same cue: bubbly throughout and expanded, with the surface just beginning to flatten. Warmth speeds this up and cold slows it down.
The float test. Drop a spoonful into water. If it floats, Modernist Pizza says, it holds enough gas to leaven the dough; if it sinks, it isn’t producing enough gas. They suggest pouring the dough’s water into the bowl first and dropping the preferment in, which saves a bowl and doubles as a final check.
An overripe poolish. Its volume has dropped because nearly all its bubbles have burst. Don’t throw it out: its leavening power is reduced but it has developed more flavor. Modernist Pizza suggests using it with some added commercial yeast in the dough, or freezing it to use later.
A ripe biga, in Forkish’s recipe, has tripled and is visibly gassy after about 12 hours at 68°F, with that alcoholic aroma.
Which one to start with
A poolish is the easiest place to start. It needs no maintenance, its timing can be set by the yeast dose, and its wet batter goes straight into the dough’s water. Modernist Pizza found it widely used by professional pizza makers in North America, though rarely by Italian pizzaioli, who mostly make direct doughs.
Try a biga if you want to follow Forkish’s biga recipe, and a levain if you already keep a sourdough starter; our sourdough pizza dough guide covers the levain side, including how the Planner accounts for it. Whichever you use, Modernist Pizza cautions against going overboard: too much preferment can make the crust overly sour, and past a point the preferment stops being an ingredient and becomes most of the dough.
For the wider family of preferments used in bread, including pâte fermentée, JayArr Bread has a guide to pre-ferments.
Sources
- Nathan Myhrvold and Francisco Migoya, Modernist Pizza (2021), volume 1, pages 298–301: fermented-flour preferments, biga and sponges, choosing a fermentation method, poolish timing and method, ripe and overripe poolish, and the float test.
- Ken Forkish, The Elements of Pizza (2016), chapter 6: the 48- to 72-Hour Biga Pizza Dough (biga formula, timing and ripeness, final mix) and the chapter introduction on his favorite doughs.