Sunday, September 6, 2009

Musings on Fermentation

Artisan III instructor, Didier Rosada, devoted a whole lecture to fermentation last week, highlighting the role of enzymes and the need for simple sugars, and stressing the relationship between fermentation activity and crust color. When there isn't enough residual sugar, the crust remains pale. So when using a lot of preferment in a formula, knowing that much of the simple sugar will be consumed prior to the fermentation of the final dough, the baker will be well advised to add a minute amount (0.5% to 1%) of diastatic malt. This is only true for yeasted breads as some sourdough bacteria are equiped with their own enzymatic system, which means that they are able to degrade their own starch into simple sugars and that the bread will have a beautiful crust without the help of malt. Alcohol participate in the formation of esters which contribute to the complexity of the flavor. The longer the fermentation, the more esters, which explains why slow bread tastes better. However not all fermentations are created equal and Didier gave us an example which I found so compelling I thought I would share it with you all. Let's take some dough which we ferment at room temperature for 30 minutes, divide, shape and put 24 hours in the cooler before baking (26-hour process). Now let's take the same dough which we ferment three hours at room temperature before dividing, shaping, proofing for one hour and baking (5-hour process). Which one do you think will yield better flavor? I was astonished to learn that the second one will give a better bread. The reason lies in the mass effect. Dough which is fermented in bulk will cool down much more slowly which means that a lot of activity has time to take place. Conversely, when you cool the dough after shaping, not much happens in the retarder. So, yes, more time is good but it depends on how it is being used. Also regarding the crust, when fermentation is done during proofing, you get a reddish color and a lot of blisters (due to the formation of microscopic chimneys through which bubbles of gas escape during baking). Blisters are considered undesirable in France where consumers treat them as the mark of a poorly made bread. By contrast, American consumers generally find them quite attractive. A matter of taste?

5 comments:

  1. OK, so this means that if you want to really boost flavor it's much better to retard the first fermentation than the one after shaping the bread... interesting. I didn't know that, in fact I usually retard the shaped loafs.

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  2. Hi, Miriam! I too usually retard the shaped loaves but then I usually do not ferment only 30 minutes at room temp. I mostly follow the Nancy Silverton method which consists in doing a 2-3 hrs bulk fermentation at room temp, dividing, resting, shaping and then (and only then) retarding in the cooler. Anyway I'll experiment with both methods and see if it makes a difference at my level. Please keep me posted as to what works best for you!

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  3. Hi,
    what means "proofing" ? Est-ce que c'est "l'appret"? (fermentation qui a lieu entre le façonnage et la cuisson)
    et "retarder"? Je me suis dit que c'était "chambre de pousse", c'est ça ? C'est intéressant pour moi, puisque je veux à tout prix bosser à l'étranger après mon BP !

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  4. Upon reading your blog on fermentation, I want to retard a sourdough (levain) dough for the bulk (first) fermentation at 40 dF overnight after doing an improved mix (Bosch Universal mixer) and one stretch & fold. In the morning, I would take the dough out and, after about 45 minutes, preshape, then shape the loaves, then proof for 2 to 2 1/2 hours (in the bottom of a cloche). I preheat the cloche lid at 500 dF, then slash and bake at 460 dF for about 40 minutes. Do you think this would result in a successful sourdough loaf?

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    Replies
    1. I would be a bit nervous about such a short room temp fermentation (concerned that the dough might not develop enough at 40F) but then I never do an improved mix. I almost always mix by hand. So I can't say that I have any experience with this method. I would be very interested in hearing about your results though. Please let me know.

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