The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Aligning Gluten Strands

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DonD's picture
DonD

Aligning Gluten Strands

I understand that the purpose of the stretching and folding of the dough during fermentation is to strengthen it and to align the gluten strands. Hamelman and many others advocate stretching and folding the dough on the bench in 2 directions perpendicular to each other in essence keeping it on the X and Y axes. James MacGuire advocates stretching and folding the dough in the bowl rotating it 180 degrees so essentially creating multi-directional axes. Does anybody know if in theory the 2 methods will produce the same results as far as elasticity, extensibility, oven spring and openess of crumb is concerned? Is it possible that the Hamelman method is better for elongated bread such as baguettes and batards while the MacGuire method is more suited for round loaves like boules and miches? Any thoughts and comments are welcomed. Thanks.


Don

Ford's picture
Ford

Time for a little polymer physics.  Bread is composed of polymers that are essentially long strings of atoms.  In many cases these strings are cross-linked or tied together in between the ends, but that is another story.


If you think of orienting these strings all in the same direction, you get the same type of orientation that occurs in a thread, or a rope.  The strength is increased in the direction of orientation.


If you orient the strings in several directions, you get the type of strength exhibited by a piece of woven fabric.


Orientation is necessary to build the structure of the bread, and the last direction in which you stretched the dough is the direction that has the greater degree of orientation.


I hope this helps.


Ford (polymer chemist, retired)

DonD's picture
DonD

For your clear and succinct explanation. Being a former chemical engineering school dropout, I never got the chance to learn about polymer physics!


Don

wally's picture
wally

Don, I have no clue as to how different methods of folding may affect the alignment of gluten strands.  However, for what it's worth, based on the class I took with Jeffrey and James I can tell you that: 1) They both used both methods of folding.  2) We did a 73% hydration straight dough baguette and the six sets of folds were all done in a bowl using a circular motion. We also did a 68% hydration poolish baguette and that was folded in the traditional manner.


Larry

plevee's picture
plevee

Does this mean that the stretch and fold should always be in the same direction - rotating 180 degrees does this - for long loaves like baguettes, and multidirectional - with a rotating bowl, for boules to achieve a stronger gluten cloak?


Patsy

DonD's picture
DonD

And for sharing your experience. I guess it's worth doing a side by side experiment using the same formulation with the 2 S&F methods.


Don

wally's picture
wally

You know, we used to make muffuletta rolls from our baguette dough, so you could actually create both baguettes and rolls or boules from the same mix and do side-by-sides (not that I'm suggesting you actually do so....).


Larry

ehanner's picture
ehanner

Great question DonD,


Where else in the world could you ask a question like the one DonD asked, and get a great answer like Ford's reply. What a great explanation to a question I have wondered about for a long time.


Now that I think back, it was Julia Child who referred to the "gluten cloak" or the cloth of gluten that is essential in the structure of bread. Thank you all.


Eric

LindyD's picture
LindyD

Great question and great response, gentlemen!  Of course, that's another process to think about during the mix.


I envision hanging a small blackboard on the wall so I can list all the things I need to remember:


Mise en place?  Check!


DDT?  Check!


Autolyse?  Check!


Direction of S&F?  Check!


Etc., etc., etc..


Hmm.  Maybe I'll need a larger blackboard...

PaddyL's picture
PaddyL

And I thought it had been banned many years ago!

dmsnyder's picture
dmsnyder

I certainly cannot match Ford's knowledge of polymer chemistry, but my understanding of how the gluten network forms during autolyse, mixing and fermentation leads me to believe that our ability to influence the orientation of gluten strands through physical manipulation of the dough is limited.


The gluten molecule forms through the combination of two smaller protein molecules - gliadin and glutenin - in the presence of water. The initial structure of the gluten network, say after an autolyse, is chaotic. Mixing, whether by machine or by hand, does two things: It stretches the gluten molecules and folds them. With mixing, the structure gets "stronger" by increasing the elasticity through stretching and the cross-links between molecules and folds of the same molecule to which Ford referred. But time itself is also important, because gluten itself and cross-links between molecules continue to develop even without mixing. I like Ford's analogy to woven fabric, but because the ongoing process during fermentation continues to be fundamentally chaotic, the gluten network structure cannot be as regular in strand spacing as loomed fabric.


I think this chaotic process dominates, even if one did all the stretching and folding in the same direction. The best example of this kind of stretching and folding of which I can think is the way laminated doughs are made. In that example, the folds are also prevented from joining by the intervening layers of fat.


I think it is notable, in this regard, that when we talk about a "regular" crumb, we are not talking about breads in which the gluten structure is uniformly formed but rather disrupted, either a) by fat (which is called "shortening" because it shortens the gluten strands - more precisely, preventing them from lengthening) or by b) bran, large solids like nuts and seeds or other ingredients that shorten the gluten strands by actually cutting them, or by c) over-mixing, which also breaks the gluten bonds.


So, my belief is that how we stretch and fold dough does not have a practical impact on crumb structure, but I am certainly open to evidence to the contrary.


David

overnight baker's picture
overnight baker

I find this all fascinating and think it's about time some people did some scientific baking to try and determine exactly what is going on here, and as soon as I'm done with NYB test bake I certainly nominate myself.


Now for a little bit of pedantry. As I understand it the term shortening has been in use for a long time yet our understanding that it 'shortens' gluten strands is fairly recent and the common name is a happy coincidence.

Mini Oven's picture
Mini Oven

Just as felt developed into woven cloth.  Felt being one of the oldest forms of textile.  And if we are using textiles for comparison, I would choose felt, the longer the wool, the better.


Spinning thread and weaving made the cloth stronger and more durable and maybe the comparison to dough is rather abstract but would it be possible... to weave a dough for the crust  and wrap it around a higher hydration dough for support?  What a vision!  The bread  basket crust... a new dimention in crusty loafing? 


I remember being so inspired by Shiao Ping's wrapped loaves.   What if the dough was one long roap wrapped around itself like a ball of yarn, risen and baked?  What would it look like?  Would it pull apart nicely?   Could this come close to being globe round?  Or would it look too complicated to be enjoyed? (Would warm proofing be global warming?)


Sounds like fun...  A wrapped pan loaf? (Would the dough spring extruded out the ends if it were free standing?)   How about a wheat wrapped rye?  (That would be a master test of sourdough timing!) 


I can't wait for next week's cooler weather!


Mini


 


 

Daisy_A's picture
Daisy_A

Hi Mini,


You ask,


" What if the dough was one long roap wrapped around itself like a ball of yarn, risen and baked?  What would it look like?  Would it pull apart nicely?   Could this come close to being globe round?  Or would it look too complicated to be enjoyed?"


Interesting that you should reflect on this. Check out this beautiful Moroccan bread made in exactly this way. The dough 'wool' is even wound onto a spool at one stage, the way I remember my mother winding wool from a larger cone to prepare to knit.


http://moroccancuisinemarocaine.blogspot.com/search/label/Mssamen-Bghrir


It looks at one point like the wool the kittens got at, but does seem to come together into a rough ball shape for baking. The final thing looks stupendous. Complicated too. I thought about attempting it but reckon it's beyond me.


Not too complicated to be enjoyed though, I hope. You can see that the author herself admits that this is a time-consuming recipe, kept for special occasions but also claims it is heavenly to eat. This is her mother's recipe. I'm just enjoying gazing at it for now!


Kind regards, Daisy_A

Mini Oven's picture
Mini Oven

That is really neat!  I was thinking a little bit thicker than noodles, although that does give me... more ideas...

Daisy_A's picture
Daisy_A

mmm shrimp, that sounds good. I also like the sound of this with honey. But then I love honey with breads. Do let us know where you go with this.   Daisy_A

Ford's picture
Ford

I purposely made a very complicated process simplistic.  Of course, there are many things going on in the process of making the dough.  The mere addition of water to flour starts the process of forming gluten, as David mentioned.  Then, there is the orientation of the molecules after the dough is formed.  That is the process that I had in mind.  When one shapes the loaf, he (she) stretches of skin of the dough and thus provides some orientation to the surface and constrains the dough during the final rise and the baking.

The interior of the loaf, however, does have some micro orientation.  The stretching during the kneading (by whatever method) has given some alignment to the individual molecules.  So that instead of the molecule being folded haphazardly back and forth on itself like a tiny tangle of fiber, the molecules are somewhat straighten out allowing for intermolecular attraction, bonding, yes, and even cross-linking, rather than the original intramolucular bonding.  This gives the structure and strength to the crumb, and allows the gluten to form tiny balloons, so that the dough can rise.

This too is a simplistic explanation, but perhaps not as simplistic as before.



Ford


 

Joanne Burek's picture
Joanne Burek

Based on the information above, a stretch and fold wouldn't have much to do with organizing the gluten strands. Intuitively it seems right, because it's only done a few times or once during the rising. I understood that the purpose of stretch and fold is to even out the temperature of the dough mass. The effect is to bring some of the exterior into the interior, and vice versa, without crushing the air holes.

DonD's picture
DonD

Based on Hamelman's comments in 'Bread', stretching and folding does align the gluten strands in addition to modulating the dough temperature. I was just curious about why in some cases the S&F is done in 2 directions at 90 degrees to one another and in other cases it is done rotationally in all directions. What I got from various responses is that aligning gluten strands can be achieved in many ways be it mechanically kneading the dough, fermenting it over a long period or by stretching and folding. The ultimate goal is to strengthen the gluten network so that gas can be trapped for the dough to rise better.


Don

SylviaH's picture
SylviaH

now that you mentioned it, about the temperature modulating!  Thanks for this interesting discussion, Don!


Sylvia

PaddyL's picture
PaddyL

It seems a bit much to me, to be 'organising' bread dough to such an extent.  I think it's just such a miraculous thing, the coming together of all the elements to make a great loaf of bread, that 'aligning' and 'controlling' would be interference.