Baking Tips: Why a Cake Sinks in the Middle and How to Stop It
Why Cakes Sink in the Middle
Baking is a wonderful pastime, but constant problems such as cakes sinking in the middle can be disheartening. Hopefully, these simple baking tips will give you a better idea of the reasons cakes sink and how to prevent it.
When it comes to cakes, there are some, such as chocolate brownies, where it doesn't matter if the mixture has sunk a bit when it comes out of the oven—it just makes for a more gooey and luscious cake.
However there are some, such as sponge cakes, where it absolutely does matter, especially if you were planning on serving it to guests. (Though there ways of rescuing a sunken cake and turning it into a show stopper, so if you're reading this because your cake has sunk and you need a way to rescue, it skip down to "How to Rescue a Sunken Cake.")
When it comes down to it, there are two main reasons that cakes sink:
- It is undercooked.
- There is not enough structure in the cake.
We'll now take a closer look at each of these to better understand how to prevent it from happening.
Cakes cook from the edges in, so the middle is the last part to cook.
This is why it's possible to have a cake that's burnt on the edges and undercooked in the middle—result that is due mainly to the temperature of the oven.
Cakes that sink are generally ones that rise in the first place, i.e. those that have a raising agent in them such as sponge cakes. Cakes that don't have a raising agent, i.e. those made with plain flour, can still sink, but the effects won't be as noticeable.
Cakes rise because the raising agent reacts with other ingredients and the heat of the oven to create little air pockets in the cake mixture that expand in the oven. The cake mixture cooks around the air pockets and holds it shape, creating a light, fluffy sponge cake.
When you have a cake that rises, you ideally want it to rise and cook uniformly. If your cakes regularly have huge domes, so they are much deeper in the middle than they are at the sides, there is a good chance your oven is too hot for the cake. This makes sense if you think about it: Cakes cook from the outside, so the edges will form a crust first, meaning the only place for the cake to rise is in the middle. Cooking for slightly longer at a lower temperature can help to give a more uniform result and prevent the sinkage that occurs when the crust of the cake has set but the inside hasn't. For example, if a cake has a suggested cooking temperature of 180°C, I will start it for 10 mins at 150°C, then turn up to 160°C.
Always check your cake is cooked, don't just go by visual appearance—though if the cake is pale and you can see the middle wobbling, you can go ahead and assume it isn't cooked.
To check that it is cooked, insert a skewer into the deepest part of the cake at the centre. If the skewer pulls out clean, i.e. no mixture sticks to it, the cake is cooked. If mixture clings to it, the cake needs longer. If the cake needs longer, but the outside of the cake is looking in danger of burning, turn the oven down by at least 20°C—there will be enough heat to cook the cake, but it should stop it colouring any further.
Another way to check if your cake is cooked is to gently press the top of the cake with your thumb. If it springs back immediately, it's cooked; if not, give it a couple more minutes, then test again.
Cakes without Enough Structure
Another reason cakes sink is because the mixture doesn't have enough structure to it.
Cake mixtures are fairly precise, and whereas if you're making roast chicken with garlic and rosemary and don't have any rosemary, you can swap it for lemon and still end up with a perfectly good meal, you can't do that with cakes unless you really know what you're doing.
Being a couple of ounces short of flour or not having enough eggs can be the difference between success and failure when it comes to cakes as without the right ingredients there isn't enough form to the cake. It's like trying to build sandcastles with dry sand as opposed to wet sand—they just don't work.
Four Things to Check If Your Cake Isn't Rising Evenly
How to Rescue a Sunken Cake
By the time a cake has sunk, it has normally cooled, so putting it back into the oven isn't an option.
If the sinkage isn't too bad, i.e. it's more of a light depression than a crater, just change your design and cover it up. A slight depression means the cake is more or less cooked so you won't get cake mixture running out when you cut into it. Use butter icing, cream, cream cheese, or another sort of frosting, and so long at the top is level after you've applied the frosting, no one will ever know. If you're icing the cake with fondant, put extra buttercream in the depression to level it out before applying the fondant.
For more serious sinkages, i.e. ones where the middle of the cake looks like it's had a boulder dropped on it, the only thing to do is remove the middle. If you have a chefs ring or cookie cutter that is slightly bigger than the sunken part of the cake, use that. Otherwise, use a spoon to dig out the middle. Remember that the only part of the cake that isn't cooked is the sunken bit; the rest is perfectly fine.
Once you've removed the uncooked part, you'll have a cake that resembles a ring. Fill the centre with a mixture of frosting and fruit, decorate the edges of the cake, and it'll look like that was what you meant to do all the time—and it's quite likely you'll get asked to make 'one of those great ring cakes' again.
Remember, many great recipes have their origins in mistakes.