Pre-ferments

Cooking Skills: Bread 2

Chapter 1 · Pre-ferments

Skill goal

Make and use a pre-ferment to give a loaf more flavour, a better crust and a longer life.

The basics

Flavour in bread comes from time. A pre-ferment is a small portion of the dough (a bit of the flour and water with a tiny amount of yeast) that you make the day before and let ferment slowly. It adds depth of flavour, a better crust and a loaf that stays fresh longer, without any extra effort on baking day.

Figure 1. A poolish day. The pre-ferment does the slow work overnight, and the dough itself takes only a few hours the next day.

The three pre-ferments in this chapter

Pre-ferment	What it is	Hydration	Time	Flavour
Old dough	A piece of a previous dough	As the original	Already fermented; use within 2 days	Mild, slightly sour
Poolish	Equal weights flour and water, pinch of yeast	100%	8 to 14 hours at cool room temperature	Sweet, creamy, open crumb
Biga	Stiff mix of flour, about half its weight in water, a little yeast	About 50%	12 to 16 hours	Chewy, nutty

Why they work

Flavour: a long slow ferment makes organic acids and aroma compounds that a quick rise can't.
Crust and crumb: the enzymes in a pre-ferment break starch into sugars that brown better, and the dough is stretchier.
Keeping: the acids in a pre-ferment slow staling, so the loaf keeps a little longer.
Little extra work: mixing a poolish takes 5 minutes.

Using a pre-ferment

Count it in the recipe: the flour and water in the pre-ferment are part of the total, so reduce the main dough to match.
Judge it by looks, not just time: a ripe poolish is bubbly, domed and just starting to sink back, smells of sweet yeast and beer, and may be a bit sour.
Mix it with the dough ingredients (the poolish into the water first, biga torn in pieces).
Reduce the yeast in the main dough, because the pre-ferment brings its own.

Pre-ferment safety

Try it

Level 1 · Start here

A loaf with old dough

2 hours 30 minutes1 loaf (12 slices)using a little leftover dough to deepen flavour

The simplest pre-ferment is a piece of dough saved from the last bake. It is already fermented, so it adds flavour and a slightly better crust. Tear it into small pieces so it mixes in.

Ingredients (12 portions)

150 g old dough (a plain dough made with flour, water, yeast and salt, from Cooking Skills: Bread 1, chapter 1 or 2)
400 g strong white bread flour
1 tsp fast-action dried yeast (about 1 tsp)
8 g fine salt
280 ml lukewarm water

Tear the old dough into small pieces and put it in a bowl with the water. Squeeze it with your fingers until it breaks down into a milky mixture.
Add the flour, yeast and salt and mix to a dough. Knead for 8 to 10 minutes until smooth and elastic.
Prove in an oiled bowl for about 1 hour, until doubled. Shape into a loaf and place in an oiled 900 g tin. Prove for 30 to 45 minutes.
Bake at 220°C (200°C fan) for 30 to 35 minutes until golden and hollow underneath. Cool on a rack. Save 150 g of your next dough for the next loaf.

Old dough

Keeping old dough: keep a piece of plain dough (flour, water, yeast and salt only) covered in the fridge for up to about 2 days, or freeze it in a bag for a few weeks and defrost it in the fridge. Don't use dough that has milk, egg or other perishable fillings.

Raw flour: flour is a raw ingredient and can carry bacteria such as E. coli, which are killed only by baking or cooking. Don't taste raw dough, don't let children eat or play with it, and wash your hands, bowls and surfaces after handling flour and dough.

Level 2 · Wet pre-ferment

A poolish white loaf

10 minutes the night before; 3 hours the next day1 loaf (12 slices)mixing a poolish and using it

A poolish is equal weights of flour and water with a pinch of yeast, left overnight until it is bubbly and smells slightly sweet and yeasty. It gives a more flavourful, open-crumbed loaf with a crisper crust.

Ingredients (12 portions)

200 g strong white bread flour (for the poolish)
200 ml cool water (for the poolish)
a pinch fast-action dried yeast (a good pinch, for the poolish)
300 g strong white bread flour (for the dough)
8 g fine salt
130 ml lukewarm water
½ tsp fast-action dried yeast (for the dough)

The night before: in a bowl, stir the 200 g flour, 200 ml water and pinch of yeast to a thick batter. Cover and leave at cool room temperature for 8 to 14 hours, until it is bubbly, domed and just beginning to sink back.
Add the dough flour, salt, lukewarm water and yeast to the poolish and mix to a dough. Knead for 8 minutes.
Prove for 1 hour to 1 hour 30 minutes, until nearly doubled. Shape and place in a tin or on a tray. Prove for 45 minutes.
Bake at 220°C (200°C fan) for 30 to 35 minutes. Cool on a rack.

Pre-ferment safety

Level 2 · Stiff pre-ferment

A biga loaf

10 minutes the day before; 4 hours the next day2 rustic loavesusing a stiff Italian pre-ferment

A biga is a stiff pre-ferment (about 50% water). It ferments more slowly than a poolish and gives a chewy crumb and a mild, nutty flavour. It is the traditional start for ciabatta.

Ingredients (8 portions)

250 g strong white bread flour (for the biga)
125 ml cool water (for the biga)
¼ tsp fast-action dried yeast (for the biga)
250 g strong white bread flour (for the dough)
10 g fine salt
250 ml lukewarm water
¼ tsp fast-action dried yeast (for the dough)

The day before: mix the biga flour, water and yeast to a stiff, shaggy dough (it won't be smooth). Cover and leave at cool room temperature for 12 to 16 hours, until it has risen, has a domed top and smells sweet and a little sour.
Tear the biga into pieces in a large bowl, add the dough flour, salt, water and yeast and mix. Rest for 30 minutes, then stretch and fold 3 times over the next 1 hour 30 minutes.
Flour the surface generously, tip the dough out gently and cut into 2 pieces. Stretch each into a rough oblong, place on floured baking paper and rest for 30 minutes.
Bake at 230°C (210°C fan) on a hot tray with a roasting tin of boiling water on the bottom shelf for 22 to 25 minutes. Cool on a rack.

Pre-ferment and steam

Pre-ferments are safe to leave out overnight because they are only flour, water and a pinch of yeast: cover the bowl with a plate or a lid (not tight) and keep it somewhere cool to normal room temperature. Don't taste the raw mixture, and wash your hands and bowl after handling it. If a pre-ferment smells of anything other than yeast, beer or mild sourness, or has mould, throw it away and start again.

Hot ovens, trays and steam: use dry oven gloves, pull the shelf out rather than reaching in, and put hot trays and tins on a heatproof surface. If you put a tray of boiling water in the oven for steam, pour it carefully with the oven door open a little and your face well back: the steam is far hotter than the water.

Level 3 · Shaping

Poolish baguette-style sticks

10 minutes the night before; 3 hours 30 minutes the next day3 sticksshaping a long loaf from a pre-ferment dough

Combine the poolish with the shaping skills from Cooking Skills: Bread 1, chapter 3, and you get a long, crisp-crusted loaf with a lovely open crumb.

Ingredients (3 portions)

150 g strong white bread flour (for the poolish)
150 ml cool water (for the poolish)
a pinch fast-action dried yeast (a pinch, for the poolish)
350 g strong white bread flour (for the dough)
10 g fine salt
190 ml lukewarm water
½ tsp fast-action dried yeast (for the dough)
1 tbsp semolina or flour for the tray

The night before: mix the poolish (150 g flour, 150 ml water, a pinch of yeast), cover and leave for 10 to 14 hours.
Mix the poolish with the dough flour, salt, water and yeast. Knead for 8 minutes. Prove for about 1 hour.
Divide into 3, shape each into a stick about 30 cm long (see Cooking Skills: Bread 1, chapter 3) and place on a floured or semolina-dusted tray. Prove for 30 minutes.
Slash each stick. Bake at 230°C (210°C fan) with a roasting tin of boiling water for 20 to 25 minutes, until deep golden. Cool on a rack. Best the same day.

Pre-ferment, blades and steam

Experiments

Experiment

With or without

The pre-ferment effect.

Make the Cooking Skills: Bread 1, chapter 1 white tin loaf and the poolish white loaf on the same day, same flour, same oven. Taste both after cooling.

Look for: The poolish loaf has more flavour, a more open crumb and a crisper crust. The plain loaf is milder and more even.

Experiment

Poolish age

Young, ripe or old.

Make three small poolishes (50 g flour, 50 ml water, a tiny pinch of yeast) and use one after 4 hours, one after 12 and one after 24 hours at room temperature, each in a small loaf.

Look for: The young poolish adds little flavour. The ripe one is best. The 24-hour one is sour and may make a slack dough, because the gluten has been broken down.

Experiment

Poolish or biga

Wet or stiff.

Make the poolish loaf and the biga loaf with the same total flour and compare crumb.

Look for: The poolish gives a softer, more open crumb and the biga a chewier, slightly denser one.

Experiment

Fridge or room

Slowing the pre-ferment.

Keep one poolish at room temperature and another in the fridge overnight, then use them in two loaves.

Look for: The fridge poolish is less bubbly and milder; it rises less in the loaf, so give it extra time. Pre-ferments in the fridge are good for a weekday.

Tasting notes

What I tried	Method or amount	What I saw	What I thought	Will I do it again?
Loaf with old dough
Poolish white loaf
Biga loaf
Poolish sticks
With or without
Poolish age
Poolish or biga
Fridge or room

Troubleshooting

Problem	Likely cause	What to do
Poolish hasn't bubbled	Too cold, or old yeast	Give it longer somewhere warmer; check the yeast date
Poolish collapsed and smells sharp	Left too long	Use it sooner next time; use a little less yeast; keep it cooler
Dough too slack	Pre-ferment over-ripe, or water not reduced	Count the pre-ferment water; use a younger one
Loaf too sour	Over-long ferment	Shorten or cool the pre-ferment
Dense loaf	Not enough rise after mixing	Give the dough its full rise; use the poke test
No difference in flavour	Pre-ferment too young or too small	Ferment for 12 hours; use 30 to 40% of the flour in it

Flour, heat and allergens

Raw flour: flour is a raw ingredient and can carry bacteria such as E. coli, which are killed only by baking or cooking. Don't taste raw dough, don't let children eat or play with it, and wash your hands, bowls and surfaces after handling flour and dough.

Hot ovens, trays and steam: use dry oven gloves, pull the shelf out rather than reaching in, and put hot trays and tins on a heatproof surface. If you put a tray of boiling water in the oven for steam, pour it carefully with the oven door open a little and your face well back: the steam is far hotter than the water.

Allergens: bread contains wheat (gluten). Check the recipe for milk, butter, egg, sesame and other seeds, and nuts, and label them if you share the bread. Gluten-free bread uses different flours and methods and isn't covered in this course.

Checkpoint: can you do this now?

I can make and judge a poolish and a biga.
I can count the flour and water in a pre-ferment as part of the recipe.
I can use old dough to improve a loaf.
I know how to slow a pre-ferment in the fridge.
I can taste the difference a pre-ferment makes.

Next chapter

Cooking Skills: Bread 2, chapter 2 is Making a Sourdough Starter: growing, feeding and keeping your own wild yeast.