The first step in making bread is to mix the ingredients together. The moment flour meets water, several processes begin. Broken starch granules absorb water, and enzymes digest their exposed starch into sugars. The yeast cells feed on the sugars, producing carbon dioxide and alcohol. The glutenin proteins absorb some water and sprawl out into their elongated coils; the coils of neighboring molecules form many weak bonds with each other and thus form the first strands of gluten. We see the dough take on a vaguely fibrous appearance, and feel it cohere to itself. When it’s stirred with a spoon, the protein aggregates are drawn together into visible filaments and form what has been vividly described as a “shaggy mass.” At the same time, a number of substances in the flour cause breaks in and blocking of the end-to-end bonds of the gluten molecules, and so an initial shortening of the gluten chains. As oxygen from the air and oxidizing compounds from the yeasts enter the dough, the breaking and blocking stop, and the gluten molecules begin to bond end-to-end and form long chains.