The Fresh Loaf

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Dough Handling?

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davidg618's picture
davidg618

Dough Handling?

The photo's below are from a recent bake, but I've seen the same phenomena on multiple previous bakes. The first photo shows the bread's crumb at the very center of the boule. One can see it's relatively closed. The second photo shows the crumb nearer the edge of the same loaf. The crumb appears much more open, to me. I'm not certain the photos illustrate it as much as my eye perceives the difference.


I think the difference is attributible to the way I preshape, and shape the boules, but I'm not certain. I shape boules following the instructions I've learned from watching multiple videos, and recently at KA Baking Center. On every boule I recall shaping the center of the loaves have been more closed than the periphery. Any comments re alternative causes, and, more importantly, how I might achieve a more homogeneous crumb will be appreciated.


Thanks, in advance.


David G.



PMcCool's picture
PMcCool

And I have a unproven notion about why.  In the first few minutes of the bake, the crust hasn't yet dried and hardened.  At the same time, heat is beginning to penetrate the outermost layer of dough, triggering a lot of activity by the yeast.  That, in turn, leads to more gas production, which inflates the existing bubbles in the dough, contributing to the loaf's oven-spring. 


As the bake proceeds, the crust dries and hardens, preventing any further outward expansion.  The temperature in the outer section of the loaf rises past the temperature where the yeast in that zone are killed, stopping any further growth there.  Meanwhile, the heat penetrates to the center portion of the loaf, which encourages accelerated growth of the yeast there.  However, with the crust having hardened and the outer portion of the crumb growing ever firmer, there's no possibility of expansion.  Hence, a tighter crumb at the center of the loaf.


Is that what really happens?  I don't know for sure.  Seems like a possibility, though.


Paul

davidg618's picture
davidg618

Oddly, after I posted this query, I thought of your hypothesis, but didn't think about the suftace drying as well. Like you, I haven't the slightest idea how to prove this. Perfhaps a more efficient steam delivery, and maintenance would partially solve the problem. I don't like using a makeshift cloche (sp?). I've tried upside-down bowls, and foil pans. Burnt myself twice, even though I wear long oven mittens--always been a bit of a klutz.


I was especially careful handling the dough gently when I shaped these loaves, but still saw this effect. It does vary, loaf to loaf.


I'll keep experimenting.


Thanks,


David G

dghdctr's picture
dghdctr

Hi David,


If you think this theory may be on target, then you can extend the time available for loaf expansion -- just a bit -- by starting at a high temp and then reducing the bake temp to maybe 425-430 after you close the oven door.  


I still have two questions, though.  What is the percentage of dark flour in the formula?  And did you ever notice a difference in crumb structure between the KA Bread flour vs. the KA All Purpose?

davidg618's picture
davidg618

Dan,


The rye flour was/is 10%--I'm doing the same formula today, but since I'm first making baguettes, I'm doing the pain au levain dough tonight, and refrigerating it until tomorrow morning.


Bread flour vs. all purpose flour: We found the crumb decidedly softer made with AP flour, less chewy. Flavor-wise, it also seemed, to me, less sour but that could be due a lot of other things too, including my palette or sense memory on two different days. The crumb's structure was slightly more closed in the AP loaves, but that slight difference could also be due many other factors. Didn't notice any significant difference in the crust.


We both like the chewier crumb, and the neigbors don't get a vote, so we're staying with bread flour for our sourdoughs. On the other hand, we like the softer crumb in the baguettes, so I've been making them entirely with AP flour, inculding my starter refreshments when I make them with liquid levain (your formula). Today's crop are made with a poolish (Ciril Hitz formula)--bulk proofing as I write.


I routinely use two different temperatures: 480°F for 10 minutes with steam, and 440-450°F depending on the shape and loaf weight, e.g. a 2lb. or greater boule I finish at 440°F, smaller boules, and batards at 450°F. We like a dark crust--more flavor--so these temperatures are slightly higher than your recommendation.


By the way, I'm really glad you've decided to remain a frequent contributor to this web.


David G.

dghdctr's picture
dghdctr

Thanks, David -- I'm happy to be here myself.


I asked about the dark-flour content because flour mixtures with higher bran levels can produce somewhat less open crumb structure, but at 10% rye I doubt that made any difference here.


And stronger spring-wheat flours will sometimes -- only sometimes -- create a gluten structure that is so elastic that it just doesn't allow the crumb to expand as much as it would with a comparable formula made from hard winter wheat flour.  Since the gluten web in a spring-wheat based dough is stronger, you might find that mixing just a minute or two longer at the higher speed will allow for more expansion.


I'm not advocating over-mixing or excessive oxidation.  But, kilo for kilo, spring wheat flours are stronger, and they need a bit longer mixing to achieve comparable development when compared to hard winter wheat flours.  I am in no way certain that this is your culprit, but, being the science-guy that you are, you might want to experiment with that.


Of course, the lack of an open crumb could just be scoring and/or steaming related -- I can't really tell from here.


A liquid levain could provide more extensibility and volume with (possibly) even less mixing than before, but it isn't as acidic as the firm levain, generally.  I think some truly crazy bread gluttons-for-punishment (like the guys who compete at the Coupe du Monde) would try using both firm and liquid levain if they wanted more volume without sacrificing too much acidity.


But you're not that kind of nut, right?


--Dan DiMuzio

davidg618's picture
davidg618

...well...


DG

breitbaker's picture
breitbaker

this intrigues me, as I also have noticed this happening in several of my bakes!  i somewhat had tossed the idea of shaping being the issue, as I think i tend to shape my edges more firmly than the centers, so if shaping was the problem, it should have been denser on the edge?  interesting hypothesis...

mrfrost's picture
mrfrost

Good to know that I'm not the only one experiencing this.