Preferment formulas: poolish, biga, pâte fermentée and levain percentages

A preferment is just part of tomorrow's flour, water and leavening fermented ahead of the final mix. Bakers reach for them because hours of slow fermentation buy flavour, dough strength, crust colour and shelf life that a fast straight dough cannot match. This article is the formula companion to the concept guide (A2 Preferments): it gives you the numbers — in baker's percentage, with worked examples at bakery scale — for the four preferments worth knowing by heart, plus a one-step shortcut for the days there is no time to build one.

The one number that runs everything: prefermented-flour percentage (PFF)

Forget grams for a moment. The number that controls a preferment formula — independent of batch size — is the prefermented-flour percentage: the share of the total formula flour that you ferment ahead of time.

PFF = (flour in the preferment ÷ total formula flour) × 100

Raise PFF and you get more fermentation flavour, more dough strength and tang, faster final proof and a deeper crust. Lower it for a milder, quicker bake. The practical ceiling is set by acidity, not taste: yeasted preferments live happily at 25–40% PFF (commonly 30–33%), levains at 10–25%, and past about 35% PFF the dough can become acidic enough to fissure during proof and bake (a single-source caution worth respecting). See the PFF-ranges table below for the family-by-family guidance.

Two housekeeping rules make the maths behave:

1. Flour always equals 100%. Each ingredient percentage = (its weight ÷ flour weight) × 100; the formula total is the sum of all the percentages.
2. Use overall baker's percent when a preferment is involved — sum all the flour and all the water (preferment + final dough) and base your percentages on the totals. Quote percentages against only the final-dough flour and your hydration line lies to you (it reads "40% water" when the dough is really at 70%).

The master method: turn any straight dough into a preferment formula

Every formula below is built the same way, so learn the move once. Pick a PFF, lift that share of flour out of the recipe, give it matching water for the preferment's hydration and a pinch of yeast, then subtract those same amounts from the final dough so the total flour, water and salt never change. Because the preferment ferments for hours and carries leavening forward, you also halve the total yeast.

The conversion-method formula card below works a full example: a straight baguette (100% flour, 68% water, 2% salt, 1.0% fresh yeast) becomes a 30% poolish version where the poolish takes 300 g of flour + 300 g water + 1 g yeast (per 1,000 g flour), and the final dough keeps the remaining 700 g flour, 380 g water, all the salt and a 4 g yeast top-up. Totals reconcile exactly — only the route changed, and total yeast drops from 1.0% to 0.5%.

Poolish — the extensible all-rounder

Poolish is equal weights of flour and water (100% hydration) with no salt and a whisper of yeast — about 0.08–0.1% on the poolish flour for a 12–18 hour build. Its high water content favours enzyme activity, so it leans lactic and mild and makes dough notably extensible: ideal for baguettes, white rolls, pizza and laminated doughs.

The poolish-baguette formula card below is a 30% poolish at 70% total hydration. Read as overall baker's percent: poolish flour 30% + water 30% + fresh yeast 0.10%; final dough flour 70% + water 40% + salt 2% + fresh yeast 0.30%. The 20 kg-flour worked example scales it to a real batch (poolish 6 kg flour / 6 kg water / 20 g yeast; final dough 14 kg flour / 8 kg water / 400 g salt / 60 g yeast) — water 6 + 8 = 14 kg = 70%, yeast 80 g = 0.40%. Build the flour from a T550 or a UK strong white (Domson Type 550, Komplexmłyn Type 550, or Windrush/Coniston strong white) and leaven with Benevia fresh yeast (or Fermipan Red instant at one-third the dose).

If timing is tight you can drive a poolish in ~4 hours with much more yeast (~1.5% fresh on poolish flour), but you trade away flavour; the time-versus-yeast ladder is in the yeast-conversion table's sibling guidance and the Weekend Bakery dosing in the data file.

Biga — strength and an open, irregular crumb

Biga is the Italian stiff preferment: 50–60% hydration, no salt, fermented cooler (16–18°C) for 8–16 hours. Being drier it turns more acetic — sharper, more complex — and builds elasticity and strength, which is exactly what an open ciabatta or focaccia crumb needs.

The biga-ciabatta formula card below is a 35% biga at 80% total hydration. Biga flour 35% + water 19.25% (that's 55% hydration on the biga flour) + fresh yeast 0.10%; final dough flour 65% + water 60.75% + salt 2% + fresh yeast 0.20%. At 10 kg flour: biga 3.5 kg flour / 1.925 kg water / 10 g yeast; final dough 6.5 kg flour / 6.075 kg water / 200 g salt / 20 g yeast — water 1.925 + 6.075 = 8.0 kg = 80%. Use a stronger flour here (≥12% protein: Windrush Strong White at 12.0–12.5%, or Italian Tipo 00 / Belle Or T65 for character) to carry the high hydration.

Pâte fermentée — yesterday's dough, and the only one with salt

Pâte fermentée ("old dough") is simply a piece of fully mixed bread dough — flour, water, yeast and salt — pinched off before bulk proof and kept for the next batch. It is the only yeasted preferment that contains salt, which changes the arithmetic: the salt and water it carries must be subtracted from the fresh additions so the loaf still finishes at 2% salt and your target hydration.

The pâte-fermentée formula card below uses 20% prefermented flour. The old dough (per its own flour) is ~100% flour / 65% water / 1.9% salt / 0.5% yeast; expressed overall it contributes flour 20% + water 13% + salt 0.38% + yeast 0.10%, and the fresh additions make up flour 80% + water 52% + salt 1.62% (reduced) + yeast 0.50%. At 10 kg flour the old dough is ~3.35 kg and the loaf still lands at 65% hydration and 2% salt. Keep old dough up to 2 weeks refrigerated (quality is best in the first 6–24 h as acidity builds gradually; do not exceed 2 weeks); freeze for longer-term storage (~3 months, general professional practice). It is usually "spiked" with a little fresh yeast because the carried-over yeast alone tends to under-leaven.

Levain — the sourdough preferment

A levain is an offshoot of your sourdough starter: fresh flour, water and a little ripe starter, built to be used whole in one bake. Two dials set its behaviour — hydration and seed (inoculation) percentage.

• Hydration: a liquid levain is ~100%; a stiff levain is 50–75% (Andrew Janjigian builds stiff levains at 70% for white flour, 75% for whole-grain). Liquid ripens faster and milder; stiff ripens slower, leans acetic, and tolerates a wider window.
• Seed %: less seed = slower, sharper. At ~21°C: 5–10% seed → 16+ h; 20% → 12–14 h; 50% → 5–6 h; 100% (a 1:1:1 build) → 3–4 h at 25–26°C (see the levain-inoculation table below).

The levain-build formula card below gives both versions; the worked liquid build (250 g flour + 250 g water + 50 g ripe starter → ~550 g levain, ripe in ~12 h at 21°C) feeds the country loaf below. Start or maintain the culture from a pure sourdough starter (Böcker Reinzucht-Sauerteig, Lesaffre Saf-Levain LV1 / Livendo LV-2) or a ready wheat sourdough (Puratos Sapore Fidelio).

The country-sourdough-levain formula card below is the canonical Tartine-style loaf: 90% white + 10% whole wheat flour, 75% water, 20% liquid levain and 2% salt. Bakers quote the levain at 20% of the recipe flour by convention; counting the levain's own flour and water in, the true hydration is ~77% and the PFF is ~9%. One key food-safety/handling note: a young levain (just doubled) needs roughly 30% more prefermented flour than a mature one to proof at the same rate.

When there's no time to build: the one-step shortcut

The O-tentic shortcut formula card below uses Puratos O-tentic Durum, an active dried sourdough component that both acidifies and leavens, at the manufacturer's 4% on flour with added water and salt — no separate preferment, no overnight wait. It will not match a mature levain's depth, but it is repeatable and fast. For pure flavour without leavening, Zeelandia "Sourdough Dry" (Superkwas) is a dried wheat-rye acidifier dosed around 1.3% on flour alongside your normal yeast.

Allergen and food-safety flags: every wheat and rye flour here contains gluten; Domson Type 550 also carries a trace soy/lupine/mustard risk; Windrush carries a soya-contamination risk. Benevia declares no allergens, but sulphites are present in the molasses used in its production (below the labelling threshold — actual ppm undisclosed; request quantified data from Lesaffre before use with allergen-sensitive customers). O-tentic Durum contains gluten (wheat), with possible mustard cross-contamination and is made on a line that also handles tartrazine (E102) — confirm with Puratos whether cross-contamination levels require an E102 declaration and the children's attention advisory under Regulation 1333/2008 Annex V. Superkwas contains gluten (wheat, rye) and may contain barley/oat/spelt, egg, soya, milk and sesame — the spec on file is dated January 2019; sesame became a mandatory EU allergen (Regulation 2021/571) from February 2023, so a current post-2023 Superkwas spec is required before including the sesame 'may contain' statement in customer allergen declarations. Fermipan Red is declared gluten-free; confirm against the current delivery certificate before use in a certified gluten-free production environment. Flour must be heat-treated — never tasted raw. Confirm all allergen statements against the current delivery documentation before use.

Choosing and converting yeast

All formulas quote fresh compressed yeast. To switch format: fresh = instant dry × 3 (so instant = fresh ÷ 3), and active dry needs ~20% more than instant and must be rehydrated in warm water (35–40°C) first (see the yeast-conversion table below). Benevia keeps 35 days at 1–10°C; Fermipan Red instant keeps up to two years at ambient and goes straight into the mix.

Fixing a formula that fights you

Most preferment problems are number problems, not technique problems — too much or too little leavening for the time, the wrong PFF, salt double-counted in old dough, or percentages quoted against the wrong flour base. The fault table below maps the common symptoms (flat sour loaf, bland dense loaf, dough that fissures, a sourdough that crawls) to the formula cause and the fix.

Buy the ingredients

• Poolish / pâte fermentée flour (T550, ~11.5–12.5% protein): Domson Wheat Flour Type 550, Komplexmłyn Type 550, Domson Bread Flour Type 750.
• Biga / strong-crumb flour (≥12% protein): Windrush Strong White, Coniston Strong White, Italian Tipo 00, Belle Or T65.
• Yeast: Benevia / NG & SF / DCL Craftbake (fresh); Fermipan Red / DCL Levure Premium (instant); Pakmaya (active dry).
• Salt: Sea Salt Extra Fine, Polish Fine Iodised Salt.
• Sourdough cultures & components: Böcker Reinzucht-Sauerteig and Lesaffre Saf-Levain / Livendo starters; Puratos Sapore Fidelio; Puratos O-tentic Durum (one-step) and Zeelandia Superkwas (flavour acidifier).