Why Do Cakes Sink? How To Stop It!

Did your cake collapse in the oven or sink as it cooled? Find out why cakes sink and how to keep a cake from falling after baking.

There's nothing worse than pulling a cake from the oven and having it collapse seconds later as it cools. Or if your cake collapses while it's baking! Once a cake sinks, there's nothing you can do. Yes, it's generally still edible, but how can we stop it from happening? What ingredients or techniques can we change to avoid cakes sinking?

Jump to:

• Reasons Cakes Sink
• How To Avoid Cake Collapse And Cake Sinking As They Cool?
• Final Thoughts

Reasons Cakes Sink

This table summarizes the main reasons cakes sink. For more information about each, please read the next sections after the table.

Reason	Fix
Oven isn't hot enough	Next time, bake your cake at a higher temperature so your leavening reacts and moisture evaporates, promoting rise
Cake is underbaked	Next time, bake your cake for longer and use a few techniques for checking your cake is done baking
Lack of structure	Increase dry ingredients or eggs, or decrease wet ingredients or butter
Too much leavening	Decrease leavening agents or change leavening agents so the cake doesn't rise too much or too quickly
Not enough leavening	Increase leavening agents or use a combination of baking soda plus baking powder to ensure your cake has enough oomph to rise tall and stay risen

The Cake Collapses Because Your Oven Isn't Hot Enough Or Your Cake Is Under-Baked

Your cakes may collapse if your oven temperature is too low. I always keep an oven thermometer in my oven to make sure it's properly preheated before I put cakes in to bake.

The oven thermometer never leaves my oven. I move it from one rack to another, as needed, but I rely on the thermometer to tell me the oven temperature. I like to use a ChefAlarm digital thermometer with an air probe attachment.

Oven heat is vital for activating baking powder so your cakes rise, and for setting the cake structure. If there's not enough heat to set the crust and the crumb inside, the cake may rise and fall.

Also, if you don't bake your cake long enough, it will sink. For butter cakes, like this vanilla butter cake, I look for certain signs before I remove them from the oven. Here are a few ways to check if your cake is done baking:

1. The skewer test: I poke the centre of the cake with a cake tester (like this one from Amazon) to see if it's still wet inside. If the tester comes out clean, the cake should be done (although some cakes are sneaky and may pass the skewer test but still require more oven time... that's a whole other story).
2. The edges: I look at the edges of the cake, which should be nicely golden brown all around, especially near the pan. The edges of the cake should have pulled away from the sides of the pan, a telltale sign the cake is baked through.
3. The tap test: I give the top of the cake a light, gentle tap/poke with my hand. It should feel a little bouncy and possibly even spring back. If you press the cake and it makes a dent and feels very "delicate" in an unset or wet-cake kind of way. The cake isn't done. It's hard to explain, but when you press a cake that's not totally baked through, and then you press it again when it's properly baked, you will feel that when the cake is cooked, it takes on a certain firmness and strength, though very delicate.
4. The temperature: use an instant-read thermometer like the Thermapen or the Thermoworks ThermoPop to measure the internal cake temperature. When it's done baking, it should read 100 ºC or 212 ºF. 

The Cake Sinks Because It Lacks Structure

If you don't include enough structure-building ingredients in your recipe, the cake may collapse. As it bakes, carbon dioxide and steam push the cake batter upward in the pan. It needs support to maintain that volume and set the height. If not, the cake will collapse on itself. This can even happen in the oven. There are a couple of reasons a cake can lack enough support.

1. Not enough gluten: I've noticed this especially when playing around with gluten-free cake recipes. Gluten plays an important structural role, even in cakes. And so, when I develop gluten-free cake recipes, if I don't add a structure-providing ingredient, like extra egg, some xanthan gum or even ground chia/flax to compensate for the lack of gluten, the cake collapses on itself. This can even happen in the oven, before it's done baking (particularly tragic!). The cake can't support all that air and height, so it falls, leaving a sunken, sometimes greasy cake that isn't very tasty or appetizing. I wrote about the process of developing a gluten-free cake made from mashed potatoes.
2. Not enough eggs, particularly the egg whites: Eggs provide structure and support as a cake bakes. Egg proteins coagulate and help set the cake, allowing it to hold the height achieved in the oven. Not enough egg means not enough coagulation, and therefore not enough structure.

Too Much Of An Ingredient Can Cause A Cake To Collapse

This also relates to a lack of structure, but if your recipe's ingredient ratio is off and there's too much of a certain ingredient, it can be disastrous because the recipe has too much of that something and not enough structure to hold it together. The main culprits in this case are:

1. Too much fat: fat adds extra tenderness to a cake, sure, but too much tenderness comes with a lack of structure and can cause collapse. Fat interferes with the gluten network. You have to find the right balance between fat-driven tenderness and structure.
2. Too much sugar: again, if that sugar isn't balanced with more eggs or more flour in your recipe, you'll get a collapsed cake and a crumbly cake from a lack of structure.
3. Too much leavener (baking powder or baking soda): think about it, the more leavener you have, the more gas will form inside the cake, and if there isn't a growing structure to support all that extra gas, the gas will escape. The cake will rise up and then collapse back down. Remember when I did the experiment to show the impact of too much baking soda? The cakes made with less baking soda rose far more. In retrospect, that was probably because the cakes with more leavener rose and collapsed, and also because the pH affects the structural proteins, preventing them from assembling.
4. Too much liquid: again, extra liquid needs extra structure, or you can run into structural issues.

Essentially, too much of certain ingredients (fat, sugar, leavening agent, liquid) can cause cake collapse, while not enough of other ingredients (eggs and flour) can also lead to collapse. Measure ingredients properly and to use reliable, tested recipes.

How To Avoid Cake Collapse And Cake Sinking As They Cool?

Knowing how to test when a cake is done baking is essential to successful baking and to avoid cake collapse. It seems obvious, but if you are baking a recipe you are familiar with and have successfully tested before, your cake may have sunk because it wasn't baked long enough, you skipped a step or ingredient, or you added too much of something. It happens. 

If you are baking a new recipe you aren't familiar with, there may be a typo the author didn't catch, and an ingredient may be missing (or perhaps too much of an ingredient was listed by accident). This also happens a lot.

For Angel Food Cakes, Cool The Cake Upside Down

A Science Theory About Cake Collapse

You might recall that, in my post about the best baking and baking science books, I mentioned reading in "The Science of Cooking" (available on Amazon) that Peter Barham claims you have to drop a cake on the counter to prevent it from collapsing as it cools. He writes that cakes collapse as they cool because steam condenses in the cake bubbles. 

The cake bubbles shrink because air can't get into those cake bubbles to replace the volume lost. Shrinking bubbles means shrinking cake, basically, and the shrinking occurs most towards the middle of the cake because the centre of the cake is softer, while the crust is too dry and stiff to contract.

Barham goes on to offer a way of preventing cake collapse, specifically stating that "Dropping the cake, from a height of about 30 cm onto a hard surface, passes a shock through the bubble walls and allows some of them to break, converting the cake from a closed to an open cell structure. Now air is able to get into the broken bubbles, and the cake will not collapse."

Obviously, I had to test this to see for myself.

Cake Collapse Experiment

I made my go-to vanilla cake recipe (which I've modified to make this white chocolate cranberry cake and this Earl Grey cake). The recipe makes three equal layers of cake, perfect for testing: I have a control sample (a cake that goes straight from the oven to the cooling rack without any jostling or dropping), plus two cakes that I dropped immediately after removing them from the oven. Fun times!

Basically, I observed more cake collapse when I dropped the cakes from 30 cm. That's exactly what I was expecting and the opposite of what Peter Barham claimed. Cakes are fragile when they come out of the oven. It seems pretty logical to me that if you drop a cake when it's most fragile, it will collapse a little from the shock. Right? I made this "quirky" video for you to illustrate my experiment.

Final Thoughts

If you found this article about why cakes collapse helpful (or you liked any other recipe on my website), please let me know in the comments below. I love hearing from you!