Is it a myth or a fact that mixing cake/muffin batter too finely can lead to a hard finally baked cake/muffin?

Question

From here: http://culinaryarts.about.com/od/bakingdesserts/r/plainmuffins.htm

The key to making great muffins is not overmixing the batter. Once the liquid ingredients are added to the dry, mix the batter by hand just until the flour is moistened, for no more than about ten seconds. Too much mixing can cause the muffins to be dry, tough or misshapen.

and

The batter should be visibly lumpy, and you may see pockets of dry flour. That's OK! It's extremely important not to overmix the batter, or the resulting muffins will be too hard.

Is there some scientific reasoning behind this claim?

Asked by Anisha Kaul

Answer

The main reason behind the claim is that muffins don't want gluten formation. Gluten in a chemical leavened product like a muffin would make it tough, rather than light, since the protein strands are so sturdy. The sturdy structures that are desired in crusty bread are a problem for muffins and other chemical leavened products.

Gluten is formed when dough is heavily mixed or kneaded, or when the dough remains wet for a long period of time. Avoiding mixing it too much is one way of preventing gluten formation.

Lots of mixing can also cause the chemical leavening (baking powder) to go flat. Baking powder is a mix of sodium bicarbonate, which will release CO2 when in contact with an acid, and an acidic salt, such as cream of tartar (or others). They are inert when dry, but when water hits them, the acid activates and starts bubbling the soda. This reaction doesn't take long to run out of steam, though, so too much mixing can pop or shake out the precious bubbles.

What seems to be subject to some superstition is the exact way to get the "right" amount of mixing. Some people say, "ten stirs only" or other little tricks, but the point is that you just want to integrate the ingredients together, and no more, and to add the liquid to the dry ingredients as close to the actual moment of baking as practical. Dry lumps in the batter are fine - they will hydrate quickly in the heat of the oven.

Answered by Sam Ley

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