A pre-ferment and a longer fermentation in the bread-making process have several benefits: there is more time for yeast, enzyme and, if sourdough, bacterial actions on the starch and proteins in the dough; this in turn improves the keeping time of the baked bread, and it creates greater complexities of flavor. Though pre-ferments have declined in popularity as direct additions of yeast in bread recipes have streamlined the process on a commercial level, pre-ferments of various forms are widely used in artisanal bread recipes and formulas.
In general, there are two pre-ferment varieties: sponges, based on baker's yeast, and the starters of sourdough, based on wild yeasts and lactic-acid bacteria.[note 1] There are several kinds of pre-ferment commonly named and used in bread baking. They all fall on a varying process and time spectrum, from a mature mother dough of many generations of age to a first-generation sponge based on a fresh batch of baker's yeast:
- Biga and poolish or pouliche are terms used in Italian and French baking, respectively, for sponges made with domestic baker's yeast. Poolish is a fairly wet sponge (typically one-to-one, this is, made with a one-part-flour-to-one-part-water ratio by weight), whereas biga is usually drier. Bigas can be held longer at their peak than wetter sponges, while a poolish is one known technique to increase a dough's extensibility.
- Old dough (pâte fermentée) may be made with yeast or sourdough cultures, and in essence consists of a piece of dough reserved from a previous batch, with more flour and water added to feed the remaining flora. Because this is a piece of old dough, it has the typical ingredient of salt to distinguish it from other pre-ferments.[note 2] Once old dough had rested for an additional 10 hours of age, the French named it Levain de Chef
On the third day, I made my bread dough using my friend's recipe. There are posts online that give mathematical formula's for adapting recipes so that one can produce a quality loaf without a lot of guesswork. I simply followed a recipe that my friend had posted on her Facebook page for making bread with poolish/old dough.
Again, I found that the cool draft in our house didn't allow the bread to rise like I wanted, so I moved the dough to the mantle in our bedroom where we keep a fire going when it is cold outdoors. It might seem a little strange to have dough rising in the bedroom until one considers that our early American history includes many one room cabins and dwellings where it would not have been unusual to have bread rising in close proximity to where the family might sleep. I love any connection with the past and having this century old starter growing in the bread on my mantel was such a treat.
Then I also have my sour dough that I keep always in the fridge. I feed it 1 cup of milk, 1 cup flour, 1 heaping tsp sugar. Feed it every several days if you use it & leave it out on the counter...If you leave it in the fridge feed it once a week if you want it more sour leave it out on the counter covered. If it comes inactive from little use, add 1/8 tsp yeast to 2 tbs warm water & stir that into your sourdough & it will make it smell better, taster better & give it pizzazz.
I always wondered why sourdough did not go bad...it is because it is preserved...The liquid at the top of sourdough when left undisturbed for a time is called HOOCH this is slightly less volatile than high test aviation gasoline & will give someone a hangover of gigantic proportions! HA!"
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