.Sourdough bread is a remarkably simple product - four ingredients - but also complicated, unpredictable and ever changing.
As a baker, once you have the flour, water, sourdough culture and salt scaled out, you have only three variables to work with in producing a fine artisanal loaf. Time, temperature and exercise.
There are two distinct chunks of time that the baker manages when making a sourdough loaf. The first is the time taken to let the levain - also known as the preferment or poolish - develop, prior to mixing the dough. This can be liquid, like pancake batter, or stiff, like a very firm dough, and can constitute anywhere from 15 - 25% of the final dough mixture Here, you have to time things right to make sure that the levain develops fully enough that when it is mixed in the final dough, it is rocking. Bubbly, active, lively. If left too long, the yeast and bacteria will become overworked and will not give the final dough much life. This activity can be moderated by the temperature - the second variable - at which the levain is proofed.
When the dough is mixed, a baker manages the third variable, exercise. Traditional techniques do not call for the dough to be kneaded (The way you might do so making bread at home), rather the dough is simply stretched and folded at regular intervals at the beginning of its proofing period. I recently acquired a commercial mixer and so do mix and knead the dough using it: this gives me greater consistency across batches of bread I am making.
With the dough mixed and folded or kneaded, we come to the second major chunk of time that the baker works with, in conjunction with temperature, and perhaps the most important time segment. That is the proofing time. Generally, a lower temperature and a longer proof time mean that one can deepen the bread's flavor and limit its sour taste. Shorter proofing times at higher temperatures will result in a bread with a less complex but more sour flavor profile. I proof my dough overnight in a refrigerator that I found on CraigsList and tricked out with a controller (so I can run it at a specific temperature). This slow, cool proofing means that my bread is not very sour but does develop a deep flavor. Overnight is nothing: it is quite common for baguettes to be proofed for 36 hours and I've seen recipes that require 4 - 5 day proof times.
There is another variable that doesn't fit nicely into this tripartite description and that is hydration (the percentage of water) of the dough. The wetter the dough, the more open the crumb and the more difficult it is to work with. I spent a few months earlier this year driving myself crazy by pushing the hydration in my bread up above 80% (that is 80% of the flour by weight). Chad Robertson's recipes all seem to start at that level and, for breads with a lot of whole grain, it can work (the bran absorbs a fair bit of water) but, for white flour, the dough becomes loose and sticky and very difficult to handle, let alone shape. I've backed things off the to the 70% range and finds that gives me a good crumb and loaves with a nice shape.
This Saturday's Bake
I'll bake a sprouted purple barley loaf for you this weekend (I think that I have baked this for some of you earlier in the year). The recipe calls for whole Kamut flour (I grind this myself), high extraction flour (I have purple barley berries that will sprout after 2 - 3 days of being moist). it is a hearty bread with a tighter crumb with great flavor.
Your Canadian Baker