Reader Mark writes:
Love the discussion of mixing! My question is, why do you get big holes in muffins when you mix the batter a lot? That seems to be contrary to what you wrote earlier this week, that more mixing usually means smaller holes.
Great question, Mark! I did indeed write that, yet also mentioned that the world of mixing is a wide one, and the same rules don’t apply to everything. Mixing a lot does yield a smaller crumb in the case of cake layers and brioche, both of which are quite high in fat. Muffins are quite a bit leaner than either one of those, which means that when you mix the batter a lot, you get a relatively strong gluten network.
That microscopic network catches and holds steam bubbles as the muffin bakes creating large bubbles, “tunnels” through the muffin’s crumb and a tell-tale conical peak on the top. The peak is the result of the added volume: the center heats last and the expanding batter has nowhere to go but up. Muffins that look like that should be avoided since they’re bound to be rubbery on the inside. The same goes for tea breads that look like treasure chests. The big hump means a tough interior. Know well-mixed, tender muffins and tea breads by their low, gently sloping crowns. Thanks Mark!