The Fresh Loaf

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Gluten gave out? Why?

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hc's picture
hc

Gluten gave out? Why?

So I shaped a sourdough boule last night and put it in the refrigerator. This morning when I took it out, this is what I saw:



Any idea why I might have gotten that blowout on the left side? I shaped carefully with good surface tension. Could I have let it bulk ferment too long (~9 hours) before shaping?

suave's picture
suave

I would say you had a big bubble in the dough left after the bulk fermentation.  During shaping it got stretched into a large flat cavity, then, as the gluten started relaxing it reinflated and burst.

xaipete's picture
xaipete

It should still bake up fine. I wouldn't worry about it.


--Pamela

AndyM's picture
AndyM

Could this be a classic case of overproofed dough?  You mention a long initial fermentation: if the dough had gone a bit too far in that initial stage, one result would be that the gluten strength might have been reduced by the time the loaf was formed.  Then, in the forming, the stretching of the gluten might have created surface tension that looked good at first, but might not have had the staying power to hold an extended, overnight proof.  Also, I think that Dan DiMuzio has written about how lower temperatures, such as those used for refrigerated proofing, can lead to a relatively larger amount of protease activity - this enzyme breaks down gluten strength over an extended proof.  If the dough came into the final proof with a bit less strength, then the protease might have had a disproportionate effect.  As for why the blowout happened mostly on one side, my experience is that all newly shaped loaves have minor imperfections - areas where the surface of the loaf has been pushed a bit further.  If these areas are put under stress, they will be the first to rupture slightly, and once a small rupture has opened up, further expansion of the dough will look to expand at the point of least resistance, which will be the rupture.

Soundman's picture
Soundman

Hi hc,


My off the cuff (conditional) answer would be the 9-hour initial fermentation.


If you kept the dough quite cool during fermentation, and the "inoculation level" was low, i.e. the ratio of flour in your levain to the total flour was relatively low, 9 hours is not necessarily a risky venture.


So I ask 3 questions:


1) What temperature did you bulk ferment at?


2) How much flour was in your final levain, and how much total flour in the recipe?


3) What hydration was the final dough?


David

hc's picture
hc

Thanks for everyone's comments. To take them in order:


Suave: "I would say you had a big bubble in the dough left after the bulk fermentation"


Ding ding ding! Now that I think about it, I remember noticing when I put it in the fridge that there *was* a big puffy patch on top. To be fair, though, I've had those bubbles before and never experienced a similar blowout. This is what they typically look like:



Pamela - you were right, fortunately. It did bake OK. I let it warm up for 15 minutes (just enough time to heat the oven to 500* F) and popped it into a hot Dutch oven as per usual. It was a little flatter than I'd like, which suggests that I did overproof ...


AndyM: Makes sense that the long first rise weakened the gluten to the point where it just couldn't contain the pressure.


David:


1) 75 degrees F the thermostat claims, though whether it's 75 in the kitchen where the dough was as opposed to wherever the heck the thermostat takes its reading is anyone's guess. Rather warm for a 9-hour fermentation, nonetheless. I was letting it go until I saw bubbles when I snipped the top ... though I will admit that I checked it later than I intended to.


2) ~70g starter at 75% hydration; 290g additional bread flour; 168g water; 2g salt.


3) Should have been at 60% hydration.


From what everyone says, it sounds like a long first proof, weakened gluten, and (possibly) increased enzyme activity in the fridge were the culprits. Now, what do I do about it? A shorter initial fermentation would be a given, but ...


1) What, if anything, should I do about those bubbles that form during shaping? Pop them before the dough goes in the fridge? Usually they're gone by the time I take the dough out, presumably having stretched out due to the expansion of the dough underneath. For that matter, should I be shaping differently in order NOT to get the bubbles?


2) If weak gluten is a contributing factor, I wonder if I should have developed the gluten more thoroughly? Or would that have just toughened up the final product? I didn't windowpane test the dough - should I knead until it forms one and forego the couple of stretch-and-folds I do during the bulk fermentation?


3) If I ever let dough bulk ferment so long that it gets waaaaaay overproofed, can I recycle it into new dough by adding it to another batch's worth of ingredients?

AndyM's picture
AndyM

Hi hc-


Glad that this turned out OK in the final bake - most breads do, in the final analysis, even if they were not exactly what had been initially intended.


For question #1, the short answer is - you can form the loaf so that the bubbles are not there in the first place.  This is mostly a matter of preference, though I think that most of the time with stiffer doughs (such as 60% hydration), they respond well to a thorough degassing when being formed.


Here is the longer answer:


As with most steps in baking bread, forming loaves can be done in a variety of ways in order to achieve specific results.  For instance, most "artisan" style loaves are shaped fairly vigorously, with a goal toward getting rid of most of the observable gas bubbles.  The dough can be treated fairly assertively, with a fair amount of pressure applied in order to achieve the desired amount of surface tension, but with care not to let the developing outer surface stick to the counter. A loaf that has just been formed should be able to stand up on its own, with no support, without much, if any, visible sagging.  The outer surface should be quite smooth, with few, if any, visible bubbles.  If any bubbles remain after forming, they can be "slapped out" with a quick, light slap to the top of the bubble, being sure that your hand does not stick to the newly formed outer surface of the dough. A loaf formed like this should be able to "hold the proof" fairly well due to the degree of elasticity and extensibility that have been re-introduced to the loaf through the forming action.  However, just like with mixing (which also develops elastacity and extensibility), more is not always better - it is possible to push too hard when forming, especially because the elasticity is what is mostly developed during intense working.  The more elasticity a dough has, the less ability it has to stretch, and the more likely it is to tear, leading to imperfections and breakdowns in the surface of the loaf.  Finding the balance, here, just like in mixing, takes practice, trial, and error.


Another method of forming is often used with high-hydration doughs, such as ciabatta or other rustic Italian breads.  These doughs are often much more sticky and difficult to work, though they might be just as "strong", in terms of gluten development.  Many bakers form these loaves very gently, with an effort to minimize degassing.  The goal is to introduce some surface tension so that the loaf can hold the proof and spring reasonably well in the oven, but also to keep as much open space as possible in the interior of the loaf.  These open spaces are the bubbles, and they result in a much more irregular, holey structure to the final bread - a result that is prized in ciabatta, for example.  To form a loaf like this, I often just fold the dough over onto itself to define an outside surface, then roll once or twice with the seam side down to get some surface tension,  Then it's done.  I've seen some bakers who don't even form their ciabatta - they dump out the bulk fermented dough, cut off a rectangle that is the approximate weight they want, and set the rectangle of dough into the proofing cloche.  Then it proofs.  Loaves formed this way tend to be baked in more rustic shapes, often with the seam side up so that the bursting of the seam is the design on top of the final loaf.  It can be quite difficult to score the top of a loaf that has been formed extremely gently and that has so many gas bubbles right at the surface.


So these are ways that loaves can be formed from dough that has fermented perfectly - in general, firmer doughs are usually formed more firmly, and wetter doughs are often formed more gently. Keep this in mind when we get to #3 below.


For question #2, I'm not sure that more developed gluten during mixing would solve this problem, for 2 reasons.  First, when gluten is "developed" during mixing/kneading, there are two qualities that are being developed: elasticity and extensibility.  I think that most kneading techniques have a tendency to develop the elasticity more than the extensibility - this is what makes the dough feel firm, cohesive, and "strong".  However, if there is too much elasticity, and not enough extensibility, then during fermentation and/or proofing, as the dough expands, it won't be able to stretch enough.  The gluten strands will break, thus working against the goal of a "strong-enough" dough.  My understanding is that the stretch-and-fold method is one way to develop some elasticity, while also preserving and increasing the elasticity of the dough, which should result in a more balanced final dough.  The second reason why I don't think further kneading is the answer is that I think the problem was that the gluten broke down due to enzyme activity, not that there wasn't enough gluten strength in the first place.


For question #3 (which brings together elements of both #1 and #2 - excellent set of questions!), handling overproofed dough can be tricky.  You can form it into loaves and bake it, but that requires some different handling.  Since there is less dough strength to begin with, the goal for surface tension in the final loaf should be reduced.  The same goes for the goal of eliminating gas bubbles.  Treat an overproofed dough very gently, don't worry if your loaf shape has minor imperfections, and consider baking it with the seam side up, avoiding the difficulties of scoring a weaker loaf that is full of bubbles.  This is a lot like the forming technique for very wet doughs described above.  Remember, the goal is not to build up the gluten strength again, because the gluten has started to break down (see #2 above).  The goal, instead, is to get the dough to just be able to hold a proof without collapsing.  As a consequence of the reduced dough strength, the final proofing time for old dough is usually reduced.  When baking an overproofed loaf, a higher oven temperature in the first part of the bake can help to encourage both that little extra spring and a slightly earlier setting of the crust structure so that the loaf can hold its shape.  Similarly, I usually vent the steam out of the oven a few minutes early when baking overproofed bread, again thinking that firming up the structure of the crust earlier will help the loaf to hold its shape.


Your idea of recycling old dough into a new mix could also work - this would make the overproofed dough into a "pate fermente".  Realize, though, that the characteristics of this pate fermente will be the same as the characteristics of the old dough - reduced gluten strength, increased acidity, and less overall vigor.  In small percentages, this should not be a big problem, especially if the pate fermente is combined with another method of leavening, such as a fresh biga/poolish, or perhaps even some fresh yeast.  The same principles would apply to any kind of pre-ferment, really - a biga, a poolish, or a starter can get old just like a dough, and if you have an old pre-ferment, you can modify your mixing to compensate.


Phew!  Well, I have gone on a bit, haven't I?  Having overproofed hundreds (probably even thousands!) of loaves in my time, this is a topic near to my heart, and one that I have spent a good amount of time mulling over and experimenting with.  Hopefully, others will be able to learn from my mistakes more efficiently than I learned from them myself...


All the best,


Andy

Paddyscake's picture
Paddyscake

definitely not! Yeah, I always gently pop the sizeable surface bubbles, using a toothpick.


Betty

hc's picture
hc

Should I even be getting those bubbles if I'm shaping correctly? I try not to degas the dough very much during shaping; is that a mistake? I'm wondering if I ought to degas it vigorously, upside down, so the bubbles will smush back into the underlying dough.

Soundman's picture
Soundman

hc,


First, thanks for your answers, they are helpful in following up. Also thanks to AndyM for his comprehensive answer on shaping.


Glad to hear your dough baked up nicely! Bread doughs are generally very forgiving.


As Andy points out, open holey textures usually come from higher hydration doughs (usually upwards of 70%). Such doughs require gentle handling to maintain the many gas bubbles in the interior of the dough.


Bubbles like the ones you photographed are common, even in relatively drier doughs. They're a good sign that fermentation went well and produced plenty of gas.


That said, your bubbles may be bigger and more of problem due to the 9-hour bulk fermentation. Given the conditions of your dough and your environment, I would think that a 5-hour bulk fermentation, with interim folding, which removes some of the gas and builds gluten strength very gently, would be long enough and would do the dough some good.


So of course I have another question: did you fold the dough during bulk fermentation? I use Jeffrey Hamelman as a guide on this issue. He says, generally, it isn't a good idea to let bread dough ferment for more than 90 minutes without folding it. Not everyone follows this rule of thumb, but it's a good guideline.


Handling exterior bubbles:


Some bakers pinch them out, or like Betty you can pop them gently with a toothpick. I have been known to graze such a bubble with a sharp knife, just enough to open the bubble. The dough of the bubble just relaxes back around the layer beneath it. You need to degas such bubbles or they will bake up into crust-enclosed air.


HTH,


David

hc's picture
hc

Thanks to you both for the detailed advice. Some comments:


I've been trying to err, if I must err, on the side of overproofing. When I first started baking this bread (based on Susan's 63% hydration sourdough recipe posted on her blog), I wasn't letting it bulk ferment or proof long enough, with the result that I got a much denser crumb than I prefer. Then Susan clued me in to the trick of snipping into the dough to look for bubbles as a way to tell when to stop bulk fermenting. For some reason, the taste and texture of my overproofed loaves are way better than the underproofed loaves were.


Here's what I did with the blown-out loaf pictured in the opening post, if I remember correctly. I mixed everything at about 8 am, let it sit for 1-1/2 hours, then did a few slap-and-folds until the dough looked and felt smooth and elastic. Then let it sit for 8 hours with stretch and folds at about 1-1/2 hours and 3 hours in. Stuck it in the fridge and left it until the next morning, when I took it out and baked it at 500 degrees almost immediately.


I like letting the dough sit for an hour before slapping and folding because it really seems like the rest time develops the gluten quite a bit, and then I only need to slap and fold about 10 times before the dough comes together. I learned this from a video I found somewhere, though I don't remember where. (David, interesting you should mention Hamelman's advice about folding, because that's why I've been doing the stretch and folds!)


A follow-up note: I tried again a couple of days ago with a 7-1/2-hour bulk fermentation, followed by overnight refrigeration, followed by a 3-1/2-hour proof before baking. I didn't actually thoroughly degas the dough before shaping but I was a bit more assertive with it than before, and though I still got some bubbles on top, they weren't as big as they usually have been. I baked without popping or otherwise disturbing the bubbles (they had mostly vanished by the time I took the dough out of the fridge anyway) and they seem to have left no trace in the finished loaf.


This brings up another question. Why does one bulk ferment for a long time before shaping, then let proof for a relatively short time before baking, instead of the other way around (bulk ferment for a short time, shape, then proof for a long time)? In other words, what's the benefit of allowing the dough to double (or however long you let it go) before shaping it and letting it double again before baking? Is it a flavor thing or a rise thing or both?


I'm also going to start experimenting with different hydrations. Will a wetter dough ferment faster than a drier one, just like a wetter starter ferments faster than a drier one?

Soundman's picture
Soundman

hc,


Your current process makes sense. And I understand the quest for maximum flavor. The big question is: at what point has the dough bulk fermented enough that it's time to move ahead to shaping? Since we're dealing with life-processes when we bake bread, the answer can be critical to the outcome. Your dough blowout is a pretty clear indicator that bulk fermentation went on too long, especially since you were folding and degassing the dough with care.


If I needed to bulk ferment for 9 hours, I would experiment with temperature. Lower temperature. But that wouldn't be without consequences, of course. Debra Wink has pointed out that reducing the activity in sourdough with lower hydration and temperature can indirectly yield more acetic acid (and this too will eventually cause the gluten to break down). So we walk a fine line when we try to extend time indefinitely in the name of more flavor.


One of your questions is easy to answer. It's both. (A flavor and a rise thing.) But it's also simply practical. You couldn't very well "proof" for 7 or 9 hours and still do stretch and folds during this step to make sure your gluten structure was strong. That wouldn't be proofing, which is a final rise before baking whose name indicates that the dough has proved it will rise and make a decent loaf of bread. If you're gonna fold the dough, you're still bulk fermenting it. And don't forget the word "bulk." This comes from the fact that professional bakers mix and bake a lot of dough and don't normally divide it into pieces until it's time to shape and proof and bake. If you're making just a single loaf, the word bulk doesn't mean that much anymore. Still, the initial fermentation is necessarily when the, uh, bulk of the flavor gets created. ;-)


The conventional process steps are, one finds over time, there for a reason. Still, I'd be the last person to say you shouldn't tinker with timings and temperatures and process order as well. We all benefit from your experimentation.


Let us see your continuing adventures!


David