So, you’re familiar with fermentation but what about a preferment? And why use one?
Whilst a preferment is an optional step, it’s essentially your ticket to baking better artisan bread. Not only do you unlock more flavour, you will achieve a chewier and glossier crumb and it will keep for longer. It’s essential when making ciabatta and will give you the best baguettes in town!
Preferments are simple and easy to set up and give you a head start on fermentation. They are a good option for beginners as they are less effort than a sourdough starter that needs daily feeding and discarding. Plus, commercial yeast is more consistent in its results.
The only downside to using preferments is that they require a little advance planning. Whether your preferment takes a few hours to ferment or it needs to be made the day before you bake, think ahead. The good news is any of these options will still come together more quickly than a sourdough starter!
What is a preferment?
Preferments are made with flour, water and commercial yeast and fall into three main types - Biga, Poolish and Pâte fermentée. Essentially, it’s a portion of your bread dough, which ferments on its own, that is made several hours or more in advance of mixing the final dough. They can be of a stiff texture, quite loose or it can simply be a piece of mixed bread dough. Once it is bubbly and full of yeast, acid and bacteria, it is incorporated with the remaining ingredients of flour, water, salt and yeast. The dough then has its bulk rise, it shaping and final proof. Unlike a straight dough in which all of the ingredients for the final dough are combined at once, bread made with a preferment is mixed in these two stages.
Sometimes preferments are mixed the day before, fermenting slowly overnight and others are mixed only an hour or two before mixing the final dough. All preferments are made with commercial yeast in the range of 0.1% to 1% of the total weight of flour in the dough and can be up to 40% of the loaf weight.
What’s the difference between preferment and a sourdough starter (levain)?
A sourdough starter/levain is made with wild yeast and bacteria and doesn’t contain any commercial yeast, whereas a preferment is made with commercial yeast. Unlike a starter, you do not refresh a preferment multiple times. Starters can live for a long time, treated correctly; preferments do their job just once. Yeasted preferments are less acidic than a sourdough starter so lend a milder flavour.
For the purposes of this article, we will concentrate on the Poolish method but here’s a summary of all three:
Biga – is made up of two parts flour to one part water and a small amount of yeast, so a ratio of 100% flour to 55% water to 0.25% yeast. Its consistency is more like dough as it is a stiff preferment with only 50 – 60% hyrdration. It is custom to add more yeast than a Poolish due to the stiffer dough taking longer to expand. Biga is an Italian term and used in many popular Italian breads such as ciabatta and focaccia. Unlike a Pâte fermentée, the Biga contains no salt. This usually ferments for 14 – 20 hours.
Effect – a biga gives your dough a lot of strength and is a good choice for weak flour or enriched bread.
Poolish – is made up of one part flour, one part water and yeast, so a ratio of 100% flour to 100% water and 0.25% yeast. Its 1:1 ratio make it a handy, simple preferment to use which is why Risen has chosen it. Again, like the Biga, no salt is used. A Poolish is a wet preferment and will have a batter-like quality due to its 100% hydration. It is Polish in origin and ferments at room temperature ideally for around 15 – 18 hours.
Effect – a poolish helps create a very extensible dough and a sweet, nutty flavour.
Pâte fermentée – is the French word for ‘old dough’ as it is a piece of fermented dough separated from the final dough after bulk fermentation and used for the next bake. These preferments are usually 60% hydration so have a ratio of 100% flour to 60% water, 1% yeast and 2% salt. It is the only preferment that contains salt. It’s a thick type of sponge commonly used in french baking. A Pâte fermentée can be stored up to 8 – 12 hours at room temperature or up to several days in the fridge. It’s an easy preferment to produce as you just reserve a piece of scrap dough and use it the next day.
Effect – a Pâte fermentée builds strength and elasticity as well as adding buttery tones to your bread.
How can you tell when it is ready?
As all three preferments have varying hydration levels, and therefore texture, signs of readiness can also vary. Essentially, you are looking for signs of peak fermentation activity – those tell-tell bubbles and a good rise.
A Poolish, a 100% hydration preferment, will have multiple small bubbles on the surface. You want to use it at its peak and not when it has fallen, as it will be over ripe.
A stiffer preferment, such as a Biga with hydration below 100%, and a Pâte fermentée tend to dome in the middle as it is rising and once it is ripe, the centre of the dome will slowly recede. This is when to use it.
Flavour – this is one of the main purposes of a preferment. An extended fermentation time means more a complex taste thanks to the organic acids. You’ll achieve a wheaty aroma and a glossy crumb.
Stronger dough – due to the development of acidity from the fermentation, this strengthens the gluten structure. Your dough will be more extensible and elastic.
Longer-lasting bread – higher levels of acidity means your bread will have an extended shelf life, sometimes lasting for up to a week.
Less time - taking 10 minutes the day before to make a preferment will save you time on the bulk fermentation the next day. As a preferment adds acidity into the dough at the beginning, less time is needed for fermentation than for a straight dough. The more preferment you use, the less time is needed for the first and second rise. The less you use, the longer the fermentation time but you get fully flavour development.
How to bake with a preferment
You can adapt any bread recipe with nearly any preferment by using baker's percentages. The Poolish method is the most common mainly because it is the easiest due to the high hydration and 1:1 ratio of flour to water with a small amount of yeast. But how much?
Based on baker’s percentages, where the weight of the flour is 100%, a poolish will have 0.2% yeast. It’s simpler to see using 500g of flour:
- 500g Risen Mighty White Bread Flour – 100%
- 500g water – 100%
- 1g yeast – 0.2%
- This will make a fairly large amount of polish so reduce these measurements by half and you’ll get a more practically-sized preferment:
- 250g Risen Mighty White Bread Flour – 100%
- 250g water – 100%
- 0.5g yeast – 0.2%
If you don’t have scales that can measure to the 10th of a gram then simply use a finger pinch of either active or instant dry yeast. If using fresh yeast, you will need to increase the percentage from 0.2% to 1% as it is less dense with yeast microbes. So, using the above measurements, add 2.5g of fresh yeast to 250g of flour and water.
In general, 1/4 to 1/2 of a bread recipe’s total flour will be used to make a Poolish. Remember to reduce your bulk fermentation time once everything is incorporated. If half of the dough’s flour comes from the Poolish, your bulk fermentation would be around 2 – 4 hours and your proof 1- 2.
To mix the preferment, stir your dry ingredients together first, then add warm water. You can also use a Kitchen aid to do this with the dough handle attachment. It will be messy and shaggy at first but continue mixing until a smoother texture is achieved. Cover with cling film and leave at room temperature for 12 – 14 hours, preferably the night before you bake.
Most preferments are added at the beginning of mixing along with the other ingredients or you can add the preferment after a short autolyse, once the dough has started to come together.
Tips for success
- You can make a Poolish or Biga from another type of flour than the one you are using for the actual bread. Why not give Risen’s Wholemeal or Spelt flour a try?
- Don’t use more than 50% of the final dough to make your preferment because this will raise the amount of sugars in the dough making the gluten network less strong due to the yeast being more active.
- Reduce the amount of yeast for a longer fermentation time.
- For recipes using a Poolish, head over to our recipes section