The Fresh Loaf

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Biga vs Poolish in Ciabatta

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drfugawe's picture
drfugawe

Biga vs Poolish in Ciabatta

Greetings,


I have been doing a sourdough ciabatta for awhile now, and liking it very much - but I have begun to think about the process, and wondering why it needed a firm biga - it calls for a 50% hydration biga, and I don't like using my stand mixer for something that firm - so I've been doing it by hand, which isn't a breeze!  Then, the next day, you have to slowly incorporate pieces of the biga into your final dough - not difficult, but more time consuming than if you had just used a 100% poolish instead.  What is the benefit of using a firm biga in ciabatta?  Why not just make it easier and use the 100% poolish?


I raise this question so I might better understand the process of breadmaking - and I suspect that there are bakers hereabouts who have this knowledge.


TIA for your response.


john

suave's picture
suave

Biga is a traditional Italian preferment.  Its low hydration helps develop acidity, which helps when you're deling with weak local flours.  Since most of our ciabattas here are made with much stronger flours insisting on using biga becomes a tad pointless unless one can detect a taste difference and prefers a particular version.  In addition you may have noticed that not only mixing biga takes more effort, incorporating it into a wet dough takes more time.  So, if you find easier - use poolish, Hamelman, for example, gives both versions, but suggests increasing amount of flour in preferment by 50% when using pooilsh.

meryl's picture
meryl

why, "Its low hydration helps develop acidity, which helps when you're deling with weak local flours. "


My question is that acidity makes a dough weaker not stronger, by encouraging proteases. So why is it written so often acidity strengthens weak flours?


Meryl

dghdctr's picture
dghdctr

I don't know precisely how to explain it, and yes -- I have asked a scientist or two to do so.  Once they start using term like "disulphide bonds" my head starts to spin.  Perhaps SteveB, who is (secretly), a chemist, would jump in and answer.


In laymen's terms, it's my understanding that the strengthening effects and the disassembling effects of acidity in dough happen simultaneously, and, at moderate pH, the strengthening effects sort of dominate, for a net effect of stronger dough.


Over time, of course, protease will win out, and any acceleration of that effect would make the eventual destabilization of dough happen at an earlier time.  But "earlier" doesn't necessarily mean "early."  It could take hours and hours.  Chilling a dough or using a drier dough or preferment can slow enzyme activity, but that will also tend to create lower pH -- which is greater acidity.  Go figure.  Nature is under no obligation, I guess, to make things simple for us.


At greater levels of acidity -- I'm guessing pH of less than 3.5 -- the deterioration of the gluten bonds overtakes the equation, and the dough can literally rip apart when you stretch it.


Please don't take this Dick-and-Jane explanation as a literal model of the process.  I just wanted to illustrate somehow that both effects of acidity can happen simultaneously (I think), and by manipulating the conditions or length of fermentation, you can push the net effect in one direction or another.


--Dan DiMuzio

SteveB's picture
SteveB

Dan, in response to your post, I began to write a long, involved technical explanation, which I just erased.  There really is no need for it.  You succinctly explained, in plain language, what is probably going on.  Even a small change in pH can substantially speed up, or slow down, various competing processes.  By just going from weakly acidic to more strongly acidic, for example, a proteolytic, dough-weakening process might overtake a disulfide bond-forming, dough-strengthening process.  Time, temperature and pH all figure into the equation.


SteveB


http://www.breadcetera.com


             

suave's picture
suave

Proteases don't really just float around in the dough, they are a function of (lacto)bacteria.  In sourdough fermentation proteolysis while beneficial is something that needs to be monitored.  Proteolytic ability of yeast on the other hand is negligible, so in preferments like biga it is of little concern. 

dghdctr's picture
dghdctr

A 50% hydration biga is pretty hard to do with American flour unless you're using a typical all-purpose flour.  King Arthur's AP would still be too absorbent to make that work easily.  Italian-grown white flour is typically weak, so a 50% hydration with their flour might translate to 57-60% hydration using hard winter wheat flour like KA's AP.


Bigas are easier to control because they ferment more slowly than a poolish.  And, as suave already mentioned, they deliver more acidity, which means more strength delivered to a very wet, weak dough.


On the other hand, if you like using poolish, go for it.  The bread will be a little different, but can still be excellent.  Poolish also is more enzyme-active, so the protease levels will make an already extensible dough even more extensible.  That's probably not a problem if you bake the same day you make the dough, but for an overnight bulk fermentation (refrigerated or not) the poolish MIGHT cause stickiness in the dough.


--Dan DiMuzio

wildeny's picture
wildeny

John: "I don't like using my stand mixer for something that firm - so I've been doing it by hand, which isn't a breeze!"


Please check the illustration in The Artisan site:


Fundamental to the formation of a biga is a flour that has stability and is not too active during the fermentation. Lacking these values, a rapid decomposition can occur.


In addition to the choice of flour and the proper implementation of the procedure, the following conditions optimize a biga:

a.) The biga should not be mixed intensely for a long time. Over-mixing the dough weakens the gluten, and causes retention of excessive gas, which causes the dough to swell quickly, and also causes a rapid relapse.
 ...


 When making 50% hydration biga, I just use my hands to mix the flour & water together with a littlt kneading only. Pretty easy (and handy).


Also, the biga can be prepared in different hydration. It's just that the higher hydration, the less time for the fermentation. Depending on when you want to work on bread making, you choose the proper hydration for the biga.

drfugawe's picture
drfugawe

All wonderful info!  I thank you all for contributing, and for trying to do so in layman's terms.


Of course, I had already used a poolish of 100% hydration in my last ciabatta, along with the same long bulk fermentation period (8-10 hours) and when I then put the final dough together, as Dan suggests, I found it to be incredibly sticky, and had no glutin development apparent (it was instead pasty).  I knew then that I had to get a better understanding of why this was happening with the poolish, but not with the biga.


Thanks again for taking the time to share this info.


john

Phyrie's picture
Phyrie

Hi,


As I wait for my very first ciabatta to ferment on the counter (Reinhart's poolish method) I was browsing the threads for information.  I have followed and read the above link http://home.earthlink.net/~ggda/Direct_Sponge_and_Biga.htm and am confused at the percentages given for different bigas.


Maybe I don't understand, but 2.5% of one pound of flour is over 11 grams of yeast!  (Sorry to mix the metric with the imperial, I'm Canadian).  Some of the measurements call for 8-10% yeast!  This can't be correct, can it?


 


Phyrie

dghdctr's picture
dghdctr

First off, realize that they're quoting weights in fresh yeast, while you're probably using instant, right?  You would want to multiply the desired fresh yeast weight by 0.4 to get the correct amount of instant yeast for a similar level of fermentation.


I'm speculating here, but if they call for a 2 or 3 hour fermentation, they'll use much more yeast to ripen the biga very quickly.


Thirdly, They might be putting all yeast for the entire dough formula into the biga, with no intention of adding any more yeast later when they mix the final dough.  So 5% yeast related to the flour in the biga might translate to 2% or less when compared to the flour weight in the final dough.


And last, "biga" used to have a precise meaning in the Italian baking tradition, with a very firm consistency and what seems like a lot of yeast when compared to French-style yeasted pre-ferments.  From American and French bakers I've talked to who have interviewed some Italian bakers, there is no longer any uniformity in defining "biga".  As I think you read on the page referenced by the link above, it can now resemble poolish or firm sponge or any hydration in between.  So biga is now more of a catch-all term in Italian baking that, in practical terms, means "pre-ferment."