Blueberry, corn, lemon poppy seed! Muffins come in several scrumptious varieties and are simple to make, but there are pitfalls to avoid. What makes the difference between a lofty, delicate muffin and a flat, rubbery lump?
The secret to muffin making is not to stir the batter too much. Why? Once flour is mixed with wet ingredients, strands of gluten protein in the flour stretch out and link up with other protein molecules. The more you mix, the stronger this gluten matrix becomes. For a dense, chewy bagel, a strong matrix is just right. But with muffins, the texture should be more delicate.
Muffin recipes are designed to create a delicate gluten matrix by minimizing stirring time. The first step is to mix the dry ingredients in one bowl, and the wet in another. This two-bowl procedure isn't intended to turn your kitchen upside down, but to decrease stirring time after you combine wet and dry. Muffin recipes also say to stir the batter just until combined, leaving some lumps.
Want to see what happens with gluten in overmixed muffin batter? Next time you make muffins, sacrifice one to science! Fill all but one section of the muffin tin, then stir the last bit of batter several minutes more. Strands of gluten will stretch out and link up, making the batter look stringy. During baking, the rubbery, experimental muffin won't rise like the others. Air bubbles have to fight through that tough gluten matrix, leaving long tunnels instead of little holes. Now you know the muffin maker's secret--be gentle with gluten!