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?