The Fresh Loaf

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Question on Degassing/S&F

Paul Paul Paul Paul Paul Paul Paul Paul Paul Paul Paul Paul's picture
Paul Paul Paul ...

Question on Degassing/S&F

I'm a little confused on whether or not I'm supposed to try to keep the degas my dough. I've also sometimes got the impression that i'm supposed to take out just "some" bubbles. Anyways, I'm really confused. When I stretch & fold, I usually do it really gently and fold in all four sides, without trying to pop bubbles.

Anyways, if someone could explain when to degas, and how much to degas , that would be really helpful.


-Paul (Paul Paul etc. etc.)

wally's picture

Degassing is done to expell excess carbon dioxide which builds up through the action of yeast.  If too much carbon dioxide accumulates it has the effect of slowing down the action of the yeast - thus curbing the fermentation process.

Hamelman recommends degassing any dough that has been fermenting for 90 minutes.

While you can punch down your dough to degass, in many cases it is better to do it gently via folds.  This is especially true with doughs where you wish to have a very open crumb in the final product - baguettes, for example.  Other doughs - ryes and those with a very tight crumb, such as bagels - don't benefit from folding for a number of reasons.  However, they still need to be degassed if their primary fermentation is as long as (or longer than) 90 minutes.

So, although degassing and folding are related subjects, they are not identical. Certain doughs benefit from folds while others do not. However, all benefit from degassing during the fermentation process.

If you are bulk fermenting dough overnight, you can degass the dough before refrigerating it and then the next morning, since the colder temperatures inhibit the yeast and thus prevent an overaccumulation of carbon dioxide.

Finally, the goal of degassing is to expel excess carbon dioxide - not to destroy the gas network that is forming and which will create the crumb structure of your final product.  So, I would recommend against punching down dough.  You can accomplish the goal better by patting down the dough enough to rid it of large bubbles, but not leave it in the same shape as it was right out of its initial mix.




dmsnyder's picture

The short answer is that all wheat flour-based yeast doughs should be degassed during bulk fermentation. This prevents the formation of huge bubbles. This was the purpose of "punching down" dough, as was often prescribed before the popularization of stretch and folding instead. (S&F does other important things too, but the question was about degassing.)

How often to degas and how vigorously is the real question. During bulk fermentation, the goal is generally to pop any really big bubbles and even out the distribution of bubbles in the dough. 

You can degas too much, which will result in a closed, dense crumb.

So, how much to degas really depends on how much gas your dough is generating., how well the bubbles are distributed, whether there are any huge bubbles, and, last but not least, what kind of crumb structure you want.

Now, you can say that, since most doughs raised with commercial yeast form more gas faster than doughs raised with wild yeast, degassing is more important with the former. However, the real answer is to watch and feel your dough and act accordingly.


Chuck's picture

Yeast wants contact with fresh flour and doesn't want to drown in its own excretions (i.e. CO2), so you'll need to pop at least the largest bubbles no matter what.

Other than that, how much degassing depends on what you're making. If your goal is something like a pullman sandwich loaf with a very tight crumb, you'll want to continually get rid of all the larger bubbles. If on the other hand your goal is something like a Ciabatta with lots of huge holes, you'll want to preserve most of the bubbles.

Just by doing a stretch-and-fold --which you'll often need for other reasons anyway-- you'll do some/much of the job of degassing. You'll probably need  to "help" the S&F  a little further though. If you want a very open crumb, just look for the largest bubbles and gently pop them, possibly by pinching each bubble between your thumb and finger through the dough. If you want a very tight crumb, you may need to push down gently with the palms of your hands all over the stretched dough before folding it.

Paul Paul Paul Paul Paul Paul Paul Paul Paul Paul Paul Paul's picture
Paul Paul Paul ...

Sounds good. I think I'll only be popping the big bubbles since i like airy baguettes and ciabatta. Thanks for your comments guys its really nice to get quick and helpful answers, ya know.


-Paul Paul (Paul Paul... etc. etc.)