In part 1 of "Bake on the wild side," I wrote about how to create a sourdough starter and some of the science behind it. In this post I'll tell how I used the starter to make loaves of bread.
There are many different ways to turn sourdough starter into bread: some easy, some complicated. My primary reference so far, Nancy Silverton's "Breads from the La Brea Bakery," follows the more complicated approach.
Silverton believes that time improves flavor and texture, and therefore most recipes in her book require a lot of waiting around, and so a batch of bread takes two or three days to make. That's a long time, but it is not a lot of active work — perhaps 45 minutes total. To help the home baker fit the long waiting periods into his or her life, she provides several sample schedules.
When I first read the recipe, I was surprised to see that after forming the dough into loaves, they go into the refrigerator for 8 to 20 hours. This step, which Silverton calls "retarding," essentially sends the yeast into hibernation while allowing the other members of the sourdough community to do their thing. The bacteria (which are one of the important communities in the sourdough starter) continue to eat the sugars and starches, improving the flavor and making acetic acid, which gives the bread a pleasant sour flavor. Enzymes work on the starches in the dough, breaking the complex carbohydrates into smaller segments that can be eaten by the yeast or simply provide some flavor.
A strong start(er)
The first step is to strengthen your starter. I like to begin a few days ahead of time, giving the starter some fresh flour and water every 12 hours (every 8 hours would be even better, but my boss frowns on messy baking experiments in the office kitchen). I pour 250 grams of starter from the current batch into a clean container, then add 150 grams of water and 100 grams of white bread flour. After stirring well, I cover it loosely and set it aside at room temperature. The last feeding should occur 8 to 12 hours before you mix the bread so that the yeast is at its peak activity.
The Country White Bread recipe has just a few ingredients: starter, wheat germ, water, bread flour, and salt. The first four ingredients are mixed in a large bowl to form a rough dough, then dumped onto the counter to be kneaded into a more coherent dough. The kneading occurs in two phases — the first is for the unsalted dough, and the second is with the salt added.
The first kneading phase begins the process of the gluten development (gluten is a network of proteins that give bread its structure). After five minutes or so, I stop kneading, cover the dough with a towel and let it rest for about 20 minutes. This rest period, called the "autolyse," enables the flour to fully absorb the water and encourages the gluten to develop more completely, resulting in bread with a creamier color, more aroma, and a sweet wheat flavor. (If you are interested in some of the science behind autolyse, see the note at the bottom of this post.)
At the beginning of the second stage of kneading, I add the salt. Salt causes the gluten to toughen — after only a few seconds of kneading I can feel dramatic changes in the dough's texture and have to work harder to stretch or compress it. I work the dough for about five more minutes and then it is ready for the first rise.
After kneading, the dough goes into a lightly oiled container to rise for a few hours. It is very slow to rise — the initial temperature of the dough was only about 73 degrees Fahrenheit (22.8 degrees Centigrade), with the peak temperature of any ingredient at just over 80 degrees Fahrenheit (26.7 degrees Centigrade) — so the rising process it is not quite as dynamic as a dough made with commercial yeast that doubles in an hour or two. Four hours of rising barely increases its volume. But I can tell that it is active, with a few bulges forming here and there, thin bubbles of dough that must be holding a particularly vigorous collection of yeast and bacteria.
Getting in shape and baking
After the first rise, I cut the dough into two pieces and shape each one into a round loaf. They go into in floured, cloth-lined baskets, then sit out for an hour or two to adjust to the new configuration, then into the refrigerator for 8 to 20 hours. The next morning I set the loaves out to warm up and make their final rise before baking. This takes quite a few hours; the actual duration depends on the ambient temperature, the strength of the starter and other factors I don't fully understand yet.
And thus, one of the trickiest parts for me is deciding when to turn on the oven. A lengthy preheat is required for the baking stone or the baking pot. Believe it or not, baking a loaf in a pot or Pyrex dish can create great results, as I learned from Mark Bittman's famous 2006 article about Jim Lahey's "no knead bread." The container is covered for the first 20 minutes or so, thus creating a steamy atmosphere that causes a breathtakingly beautiful outer crust — I still remember the first time I removed the lid from a "pot of bread" and saw the complex texture and rich color of the crust.
The loaves bake for about 40 minutes, with a 180 degree rotation or pot cover removal about half way through. Then they go onto a cooling rack for perhaps what seems like longest wait in the whole process — waiting to slice off that first piece of bread and finally take a taste of bread's wild side.
About that Autolyse Here's an interesting bit of bread science from Maggie Glezer's "Artisan Baking across America" (a bread book that I heartily recommend). "Autolyse" means "self-destruction," and the destroyed element during autolyse is gluten. When I read that I was surprised, because I thought that forming gluten is the purpose of kneading. Not quite. You want gluten that is aligned into a network, not jumbled chaotically. Bread experts believe that the delay of autolyse allows certain enzymes in the dough to detangle some of the gluten. (For a basic explanation of what's going on with gluten in bread dough, visit the Exploratorium) Another benefit from the autolyse is allowing the dough to be mixed for a shorter period, thus incorporating less air into the dough and reducing its exposure to oxygen. Oxygen bleaches the dough and destroys some of the natural fats that provide flavor.