Many of the breads included on this list are made possible through yeast and other leavening agents. What is the science behind yeast? On a basic level, yeast is a single-celled organism that lies dormant until it is activated by warm water. It then feeds on the sugars in flour and any sugar added to the dough, producing carbon dioxide that causes the dough to rise. Yeast is the key to many raised breads, and it helps create the distinctive flavors and aromas that we associate with bread.
Yeast is not the only leavening agent that gives us wonderful bread, though. Baking powder and baking soda are used in quick breads such as banana bread, biscuits, muffins, cakes, and soda bread. They work more quickly, relying on the chemical interactions between acidic and alkaline compounds to produce carbon dioxide. These reactions cause the bread to inflate, but the process yields a different texture and flavor compared to yeast-risen breads.
Gluten is another key component in bread-making. Gluten is a stretchy network of protein molecules that is present in grains such as wheat, barley, and rye. It is responsible for the bounce of ramen noodles, the chewy texture of pizza crust, and the interior structure of bread. Gluten is formed when flour and water are mixed together. In simple terms, the gluten molecules in the flour “team up” to form longer chains that stay attached together. As the dough is mixed, kneaded, and allowed to rest, more bonds develop. That is why the longer a bread is kneaded, the more likely it is to be chewier. Check out this excellent resource from Scientific American that explores how gluten works in more technical detail.
Have you ever been to Japan and wondered, “why is Japanese bread so fluffy and soft?” While most of us have not had the opportunity to visit Japan, milk bread delights people around the world with its fluffy, mochi-like texture. So why is biting into Japanese milk bread akin to indulging in a delicately sweet, pillowy cloud? The secret is a Japanese-invented dough called tangzhong. This involves adding cooked-flour dough to the bread mixture. According to professional baker Daniel Tay, “The Japanese realized that by cooking the flour, the dough absorbs all the water. This cooked dough is added into the rest of the bread mixture, which gives a moister mouthfeel.”
In this method, equal parts flour and boiling water are mixed in a pan. Once it has cooled, this mixture is added to the actual bread mix being prepared for baking — the goal is that 5-10% of the mix is comprised of the tangzhong dough.