Why don't my cakes rise

Question: Why do cakes rise more in the middle than on the edge?

It makes you desperate: You try so hard to pour the dough evenly into the cake tin, but it doesn't work. When the kitchen clock rings and you take the finished cake out of the oven, it is thicker again in the middle than on the edge. Box cakes there are usually burst open. Why is that actually?

“In the middle of the cake, high temperatures are reached much later than on the outside of the baking pan,” says Wolfgang Schwack, Managing Director at the Institute for Food Chemistry at the University of Hohenheim. "Therefore, the cake in the center has a lot more time to rise."

The cake pan efficiently conducts the heat from the oven to the edge of the cake. The dough is done quickly there and bakes through. The proteins network in it, explains Peter Barham, physics professor at the University of Bristol. "Since the dough is hotter at the edge, it stiffens faster there." He opposes the baking powder there more resistance.

Baking powder makes a dough rise by releasing the gas carbon dioxide when the temperature is not too high. The gas forms tiny bubbles in the dough, causing it to expand. This happens most strongly where the dough has been runny the longest - in the middle of the cake. That's why a hill forms there. On the other hand, the dough will no longer rise on the already baked, firm edge.

Like lava from a volcano

But there is also an additional, heat-independent reason, says Schwack: “The cake sticks to the outside of the baking pan. In the center, on the other hand, he has no resistance. ”When the cake rises, he simply takes the path of least resistance.

The top layer of the cake is also always warmed up faster and therefore more cooked than in the middle. "This can create a very rigid skin," says Barham. “Under the pressure of steam and carbon dioxide, which are created in the cooler interior, it then bursts.” This is comparable to a volcano from which the lava flows out.

Even with yeast, but not with pizza

The same effect can be observed with yeast dough. It is not the baking powder that makes the cake rise, but the yeast microorganisms that break down sugar and produce carbon dioxide. But the same applies here: if the cake bakes through faster on the edge, the carbon dioxide formation will stop there sooner.

"Incidentally, it is exactly the opposite with pizza," adds Schwack: You don't use a baking pan there and the weight of the topping presses on the dough. This is how you get a high edge on the outside.

If you don't like misshapen cakes, you can try wrapping something around the baking pan, for example with aluminum foil and a wet cloth in it. Some cake baking fans swear by it. The trick is not to let the cake pan get hot too quickly. Then the cakes should rise a little more evenly.

03/23/2012 - BO

March 23, 2012