Biga v. Poolish

> 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).

sPh

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.

BROTKUNST

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.

Paul Kobulnicky

Baking in Ohio

Sorry ... Spring of 06 issue. 

Paul Kobulnicky

Baking in Ohio

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 little
bakers yeast. The ratio of flour to water is 50 - 50 by weight.

Biga-- Italian for the same thing except the biga can be like a
poolish or very firm.

The above are both yeasted.

Chef-- a dough-like starter that is either an unrefreshed levain or a
piece 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 unrefreshed

Sour-- 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 plain
starter.

Sour = levain - again it depends on the consistency of the starter.
(Sour batter-like, levain dough-like) - The difference between these
terms and the ones above is that they represent the term that
indicates that the starter is activated.

Chef, levain, biga natural, mother, and sour contain only natural
yeast cultures.

All of the above are often referred to as either starters or sponges.

They are also preferments.

Hello everyone! I’m new to this forum, and new to baking. As I get deeper into the science and art of bread, it’s becoming increasingly clear to me that preferments are the backbone of bread making.

I’m not ready for sourdough yet. I have commitment issues. And I don’t bake the same kind of bread often enough for a levain. So for now (until I get more educated), I’m focusing on poolishes and bigas (that’s just a delight to say!).

I know bigas are Italian and hydrated at 60 to 70%, and poolishes are hydrated at 100%. What I’m not really sure of, is which preferments are best for what kinds of bread? Are bigas and poolishes interchangeable? 

Sorry, I tend to go on. And on. And on. As I said, I’m new here, so please be kind!

After literally years of trying to make the Crocodillo bread from TFL, I have finally come to an agreement with my dough, and while I may never see huge, beautiful holes in my bread, I have achieved a wonderful, chewy tooth, and a flavor reminiscent of German Hard Rolls that I ate as a child...A fair compromise.

My question, please.
I use a 50-50 poolish, which I measure out by weight.
I then feed and water the remaining poolish not used. I leave it on the counter for a few hours, then fridge it for a day or so, and repeat.

My "franken-poolish" has now made several tasty, chewy, batches of Pugelese-type rolls, but the "f-p," has not really turned very sour. "Nicely tart," is how I would describe it.
I just put today's fed remainder out on the porch to encourage some wild yeasty-beasties to join the flour party, but read in a previous comment that the commercial yeast I used to create the original poolish will overrun the joint, eating the maltrose, and starving out the native flora... :(
I mean, what I am doing works, which in itself is a minor miracle. I SO love "the stretching of the dough," every 20 minutes, and I've learned so much about treating the dough gently, and lovingly folding it over in its little oil-lined container.

But I kinda want to get a little of that nice SD flavor I had once upon a time when I made a starter from scratch...
So, will my fed poolish ever "sour," or should I just use it up in the next batch of bread, and make a "proper" sourdough starter?

The whole "yeast is yeast," thing does and doesn't work. Yeasts have different flavor personalities, as well as different dominance behaviors. If commercial yeast is too pushy for a starter, I'll go back to the old-fashioned way.
Thanks for any advice/explanations you can provide. Even if just a "Won't work," or "Eventually," reply.

~M