ok. another stupid question from newbie here.
what is the difference between a biga and a poolish and a preferment? when does one become the other? inquiring minds and all... :D tia!
> what is the difference between a biga and
> a poolish and a preferment?
Preferment is any technique that combines a moderate percentage of the total flour for the recipe (20-30%) with a tiny amount of leavening (yeast or sourdough starter) and some of the total water and lets it develop for a period of time (usually overnight, but can be 1 hour to 1 week).
Biga and poolish are both types of preferment. Poolish is generally higher hydration (soupier); biga generally lower hydration (firmer). I don't have a book with definitions at hand, but off the top I would say poolish is 100% or more hydration; biga is 70% hydration. At least in Rose Levy's terms, a sponge is like a poolish but contains all of the water and is quite thin (I have seen other definitions of sponge).
Some recipes use one, some the other, some both. They generally accomplish the same purpose IMHO.
When a pate fermete is purpose-made (rather than saved from scrap dough), it is similar to a biga except it includes salt and is kneaded a bit then put in the fridge overnight (or for a few days).
The (Polish/Austrian) Poolish is the more or less official transition from the sourdough formulas ... always liquid and, as I understand it, mainly used to enhance the flavour of the later loaf. (More liquid results in more biochemical activity). Usually the poolish is fermented at room temperature and the amount of yeast depends on the time you want to ferment the poolish (less yeast, more time, different flavour due to increased acidicity and longer shelf life)
The main function of the (Italian) Biga is to enhance the strength of the dough - compromising the extensibility with that to a certain degree (you don't want that in every formula). Of course the Biga has also a positive influence on coaxing flavour out of the starches but Italian flours are said to be weak - that's were the prime use of the Biga originated. 'Biga' is actually a very vague term ...although commonly in the US we understand the 'firm' preferment without salt under this term.
The (French) Pate Fermentee is firm too, of course, but it's actually an aged miniture version of your later dough - and therefore greatly different from the Biga.
The (English) sponge is by the way similar to the Poolish, yet with less Hydration. This little firmer than poolish preferment builds more strenght for the later dough but still drives an increased amount of flavour out of the starches ... often used in sweeter dough, that are weakend from the sugar. (Sugar is counterproductive for gluten formation, just like salt)
Now, like with anything you read, take my words with a grain of salt and when you read something about preferment, check if my quick and incomplete summary holds some water.
If poolish adds flavor, and biga adds strength, may I conclude that one can mix both to get something even better? Sorry if the idea sounds absurd...
=== If poolish adds flavor, and biga adds strength, may I conclude that one can mix both to get something even better? Sorry if the idea sounds absurd... ===
A lesson that I learned the difficult way when I first started blending coffee was that mixing two good coffees might product a good result, might product a mediocre result, and might produce a very bad result depending on the variety and percentage mixed. I later observed this in various manufacturing processes as well: when you have two feedstocks approved as equivalent ingredients mixing them may or may not work.
The same applies to bread recipes in my experience: it all depends on the recipe and the blend. I have certainly seen recipes that call for both poolish and biga (RLB's baguette recipe comes to mind) but you either want to use a proven recipe or be willing to get some bad results on the way to developing your own.
IIRC this is what Floyd experienced when he was a tester for Peter Reinhart's _Whole Grains_ while Reinhart was developing his "epoxy" method: they had to get the mixtures and order of mixing correct because small changes were producing radically different results.
The San Francisco Baking Institute's Newsletter devoted a whole issue to the matter, including the question of whether a preferment was at all valuable, a few issues back. It was the cover article and is available online at http://www.sfbi.com click on "news". I'm not sure that any preferment is better than working a natural starter but they are all clearly better than a quick loaf using massive amounts of commercial yeast IMHO.
Baking in Ohio
Sorry ... Spring of 06 issue.
wow thank u for these awesome explanations! i appreciate yall's knowledge very much!
In one of their section, they discuss Direct and Indirect Methods of Bread Baking, which give you a general idea about biga and different formulas for different fermentation time. They also define what Poolish is.
Poolish-- Is French for a mixture of flour and water and a littlebakers yeast. The ratio of flour to water is 50 - 50 by weight.Biga-- Italian for the same thing except the biga can be like apoolish or very firm.The above are both yeasted.Chef-- a dough-like starter that is either an unrefreshed levain or apiece of dough saved from the previous day's bake.Levain-- a chef that has been refreshed with flour and water.Biga Natural-- same as levain, but in Italian.Mother-- this is a batter like starter of flour and water that is unrefreshedSour-- a mother that has been refreshed with flour and water.Mother = chef - it only depends on the consistency (chef dough-like,mother batter-like). Most people here in the US call this just plainstarter.Sour = levain - again it depends on the consistency of the starter.(Sour batter-like, levain dough-like) - The difference between theseterms and the ones above is that they represent the term thatindicates that the starter is activated.Chef, levain, biga natural, mother, and sour contain only naturalyeast cultures.All of the above are often referred to as either starters or sponges.
They are also preferments.
wow! thanks for this willard!!!!
so a question...natural yeast cultures mean a "sourdough" culture?
or does it include using an active dry yeast or an instant yeast?
is there a name for when you use active dry or instant yeast?
I have seen "commerical yeast" or "processed yeast" for stuff you buy rather than grow yourself. But as Rose Levy likes to say, all yeast is natural. The yeast we buy in jars has been cultivated from brewers yeast for 150 years or so, but it is just the most common of what we call "wild yeasts" today and can be found in the soil of any wheat farm.
sPh are you sure about that? Isn't that the same as saying that chihuahuas are the same as their wild wolf ancestors? But I don't think any of us imply that commercial yeast is unnatural, just not wild because as you say it's domesticated. Now I'm not being facetious. Is this a fact? Is there an article you can link?
there is less difference between dogs and wolves than between frogs in a single pond.
The Wikipedia article is fairly good I think. It leads among other places to a BBC special on yeast:
=== Yeast became more standardised when distillation of baking yeast was first developed in the mid-19th Century. This provided sufficient yeast for the rapidly-increasing population of the western European Industrial Revolution. The basis of the distillation was originally a wort, or infusion of grain, made up of wheat, rye and malted barley. Sometimes an infusion of potatoes and sugar was used ===
Well, when discussing sourdough versus preferments, which is I think what bluezebra was asking about, there most certainly is a difference between commercial and wild yeast. Specifically:
1) commercial yeast will churn away quite happily at a neutral ph
2) commercial yeast can consume maltose
The end result is that a blend of flour and water, innoculated with commercial yeast, will not develop that characteristic sour flavour of a wild starter because the commercial yeast basically starves out the acid-producing bacterial (which feed on maltose).
So, yes, there is a big big difference between a wild yeast sourdough culture and a commercial yeast preferment. The former will never include commercial yeast (though many will use a small amount of commercial yeast in a sourdough loaf in order to decrease rise times... of course, such a bread won't have the same level of sourness as one made exclusively with a wild culture).
Which implicitely gets back to bluezebra's question: a biga/poolish/etc, which use commercial yeast, are collectively referred to as preferments. But a sourdough starter is just that, a sourdough starter.
Willard was heard to mutter....
Biga-- Italian for the same thing except the biga can be like apoolish or very firm.
The only source I have seen that agrees with that is Reinhart. All other sources indicate that a biga is quite firm, around 55 to 60% hydration.
All in all, until I see other sources corroborating the it can be firm or liquid hypothesis, I will continue to believe the defintion of a biga as a firmer preferment is correct.
I have read that bread is enhanced by a complex of factors, some of which grow best in warmth, others that produce better in cold. So I have been allowing my poolish an afternoon and overnight in warm. Then I refresh it and let it sit for the same period in the fridge. I then give it a few hours to warm prior to use. I think that it really enhances the flavor of the bread.
i put my pate fermente int eh fridge for about 10 hours and it hadn't risen and without thinking picked it up - did I ruin it? or can i put back in the fridge another 10 hours?
thanks for all your help!