Flour is kind of glorious: the basis of everything from delicate pastries to hearty breads, it has as many applications as the imagination can conceive. When mixed with water, it changes from an unremarkable white powder into a sticky glue and then into a cohesive ball of dough. After baking, the texture changes again, giving a firm, dry product that bears little resemblance to any step earlier in its production. Isn’t cooking amazing?
Flour owes most of its special properties to one class of proteins: the glutens. This is further divided into the gliadins and the glutenins, each with a particular role in the final structure of baked goods.
The glutenins are about 1000 amino acids long, and they begin and end with cysteine units—amino acids that contain sulfur. In the presence of oxidizing agents (oxygen, compounds produced by yeast, or dough improvers used in commercial breads), two cysteines join together by the sulfurs to link two chains. This end-to-end linking creates chains of hundreds of glutenins bonded by strong sulfur bonds.
The middle sections of the glutenins also bond, but more weakly. They form hydrogen bonds, when electron-poor hydrogen atoms hang out near electron-rich electronegative atoms like nitrogen and oxygen, and hydrophobic bonds, when non-polar areas clump together to avoid being near polar areas—like the separation of oil and water. With the long sulfur-connected chains and the weaker associations of the middles of the chains, you get a large, highly connected network of proteins that is called gluten.
The glutenin network provides the springiness of dough in addition to most of its structure. The individual proteins have sections of loops and coils that depend on the interactions of particular amino acids. When you push on the dough, these compress like a spring, but when you remove the pressure, they also stretch back out like a spring.
We talked about two kinds of gluten proteins—glutenin, which we’ve discussed, and gliadinin. Unlike friendly, interconnected glutenin, gliadinin doesn’t play well with others and curls up into balls by itself. It turns out that this is also important for the dough, though, because the compact nuggets of gliadinin act like ball bearings within the glutenin network. They let pieces of the glutenin network slide past each other without getting in each other’s business, making dough malleable and soft.
This is really only the tip of the iceberg of the science of bread, but it has to suffice for now. Time for some bread making.
This bread rises overnight, perfect for those of us who can’t (unfortunately) stay home and slave over bread all day. The long rising time means that you use less yeast, and it allows the bread to develop really good flavors.
Yield: 2 loaves
6 c. white flour
1 t. instant yeast
1 t. sugar
3 t. salt
3 ¼ c. water
In a large, greased bowl, combine the dry ingredients. Add the water and mix until combined. It will be sloppy and not look like bread dough, but you have to believe. Cover with a towel and let rise about 18 hours.
With floured fingers, fold the edges of the dough ball toward the center, lightly pressing down. Turn the bowl and go around the ball several times. Let rise for two more hours.
About half an hour before the end of this rise, preheat the oven to 450 degrees F. Place an oiled pot with a lid (I used a cast-iron skillet and the bottom of a cake pan) into the cool oven to heat with it.
At the end of the two hours, carefully take the hot pot out of the oven, and transfer half of the dough into it. Cover with the lid and bake for 30 minutes. Remove the lid and bake 15-20 minutes more, until the crust is golden brown.
I kept the second half of the dough in the fridge for two days and baked it in a similarly pre-heated pot. It was slightly flatter but still delicious.