What is a Pre-ferment?
Teresa L Greenway all rights reserved worldwide April, 2015
A Pre-ferment is a pre-fermented dough (or leaven build) which is added to the final dough to impart certain characteristics.
Leavening is something you use to leaven or make the dough rise.
There are many words used to describe the different leavenings available for raising dough. Leavening can include commercial yeast, wild yeast or chemical leavening like baking soda/powder. We will leave out the chemical leavening in these descriptions. Confusion often happens when describing commercial and wild yeast leavens because of the similarities between them.
The names of some of the popular commercial baker’s yeasts are:
- Cake yeast – fresh yeast pressed into a small cake.
- Quick yeast – a yeast that was formulated to be twice as fast as fresh cake yeast
- Instant yeast – yeast formulated to be even faster than quick yeast and have the ability to activate directly in the dough. It is usually mixed in with the dry ingredients and activated with hot liquid.
The types of some of the popular natural or wild leavenings are:
- Sourdough Starter or culture – A stable water/flour mixture cultured with wild yeast and lactobacilli.
- Levain – a French word for leaven, usually a build in the mixing process.
- Desem – a Flemish starter made with whole wheat flour.
- Barm – a starter made from the foam from fermenting liquor.
- Natural Leaven – this sometimes means wild yeast culture or can mean old dough.
- Chef – is a French word which means a piece of old dough or starter used as a culture for building the next batch of dough or Levain.
- Sauerteig – German for sourdough starter.
A pre-ferment is a mixture of flour and water, and sometimes cracked grains or other ingredients that are mixed with a sourdough starter or commercial yeast, and left to ferment for several hours or overnight, usually at room temperature. When the pre-ferment is done fermenting, it is incorporated into the final dough.
Pre-ferments are called by different names and have different properties.
Some of the names for pre-ferments are:
- Sponge – a mixture of flour and water and/or other ingredients, which can have a hydration of 70 – 100 % and is made using only a portion of the recipe’s ingredients. It is allowed to ferment overnight, with the rest of the ingredients being incorporated the next day, into the final dough.
- Poolish – A preferment using flour and water, it usually does not contain salt and uses a small amount of commercial yeast. It is often around 100% hydration.
- Biga – which is an Italian type of preferment, uses commercial yeast and is thick dough of around 50 – 60 % hydration, it also usually uses a small amount of commercial yeast.
- “Old Dough”- also called Pate Fermente,is another kind of preferment and is a piece of dough from a former batch of dough saved and used for subsequent batches of dough, it usually contains salt and the hydration is whatever the original dough was. It will contain either commercial yeast or wild yeast.
- “Motherdough” meaning the original cultured dough which is used to produce all subsequent dough. I use it to mean a cold fermented starter at 50 – 80 % hydration and optimally kept refrigerated at around 42 – 48 degrees for several days before use. It contains wild yeast. I took the word “Motherdough” from a San Francisco bakery’s use of the term “Mother Dough,” describing their starter which is a cold ferment.
- Levain is a French word for a leaven or as a stage or build of dough. It is sometimes made from wild yeast and sometimes commercial yeast, it can be any hydration.
- Lievito Madre is a low hydration pre-ferment usually at 50% hydration which is made using a sourdough starter.
With the renewed interest and experimentation in Sourdough and Artisan breads, I hope that preferment names will come to include both wild yeasts and commercial yeasts interchangeably.
So a Biga may just mean a low hydration preferment with either commercial yeast or wild yeast used as the culture and a Poolish might be the higher hydration preferment using either commercial yeast or wild yeast. It is already common for the terms to be used interchangeably and can cause confusion when done so. It seems to make more sense to call pre-ferments by their hydration level or intended use and have their meanings more universal.
A pre-ferment is used as a “build” to bring to the final dough different desirable qualities. It brings acidity, which promotes flavor and strengthens the dough, it brings a larger amount of bacterial and yeast activity to the dough for leavening power. It is used as a tool to impart flavor characteristics depending upon the type of pre-ferment used. Pre-fermented dough also helps make the dough more digestible. Basically, it helps a baker to extract the optimum flavor and nutrients from the grain.