Why Do Cupcakes Sink?

Just last week I was baking a big batch of banana cupcakes for a custom order. I made sure that everything was right and took them out exactly when I was supposed to. The air was filled with sweetness and the cupcakes came out looking absolutely perfect, only that 15 minutes later I found myself two trays of the saddest sunken cupcakes. 

It was such a disappointing sight. Imagine, all that time and hard work going to waste and having to start over. Of course, this put me on a quest to find out exactly why are my cupcake sinking. 

I’m Angie, I’ve been baking cupcakes for over 10 years yet even I still mess up sometimes. After a series of in-depth research and reflecting on my own experience, I’ve discovered the following reasons why cupcakes sink and I’m here to share these tips with you. 

Let’s get into it!

Reason 1: Leavening Agent Not Working

If your cupcake isn’t rising properly or is sunk in the middle, it could be because your leavening agent is not doing its job. Expired baking soda/powder loses its potency and isn’t able to provide enough leavening effect on our baked goods. 

Moisture and exposure to the air and surrounding smells will weaken the baking soda, therefore baking soda and powder that is not properly stored can also lose their potency as well. 

How to Fix It: to make sure your cupcakes don’t sink because of your leavening agent, do the following test before you start baking. 

• Place a tablespoon of baking soda into a small bowl.
• Pour a bit of vinegar, lemon juice, or another acidic liquid over the baking soda.
• If the mixture fizzes and bubbles, the baking soda is still good.

You can find more information on baking soda and powder in Baking Basics. 

Reason 2: Temperature Too High or Too Low

Baking is a science and as I’m sure your lab experiments from middle school would have shown you, the temperature can make a huge difference.  

If your oven temperature is too high, the sides of your cupcakes would rise very quickly, not leaving enough time for the center to catch up. By the time every part of the cupcake is cooked through, the sides would become brown or burnt. 

Taking your cakes out earlier, however, would give you an equally sunken cupcake because the center that is undercooked would fall flat once it’s cooled as it hasn’t reached the point of rising yet. 

How to Fix It: make sure to have an oven thermometer and always set your oven temperature accordingly. Also, do not open your oven throughout your baking time to check on your cakes too much because that will cause the inside temperature to fluctuate. 

Reason 3: Overmixed Batter

If you’ve been baking for a while, you’ve probably been told not to overmix your batter. You may not have known the reason behind why, but now you do. Your sunken cupcakes are why.

Now we know that mixing our batter helps incorporate air into it. The air helps our cakes expand and is what gives them volume and fluffiness. However! It is important that we don’t overdo it. 

Mixing for too long can cause gluten to develop more than we want it to, which makes your cake tougher and less likely to rise. On top of that, the extra air in the batter will collapse when the cupcakes bake which results in a sunken center. 

How to Fix It: stop mixing as soon as all the ingredients have been incorporated and look homogenous.

Reason 4: Overfilled Liners

Logically you might think that the more you fill your cupcake tins, the bigger your cake will get. But this is only true to a certain extent. I know because I have made this mistake too many times.

The reason why we should only fill our cupcakes about ½ to ⅔ the way is that your cake will rise and will cling onto the sides of the pan. If your tins are filled too full, it’s easy for your batter to overflow. Once your cake cools down or finishes rising, the center will deflate which causes a sunken look. 

How to Fix It: Most recipes tell you how much you should fill your cupcake liners, but the rule of thumb is to always fill it up to ⅔ the way leaving enough space for the cake to rise without overflowing.

Reason 5: Not Following Recipe

Using too much or too little of certain ingredients can cause your cupcakes to sink. If you happened to have added too many wet ingredients without enough dry ingredients to balance it out, your cupcakes may not rise. Vice versa. 

Adding extra ingredients to your recipe or using substitutions can also lead to your cupcakes sinking. (in my case – the bananas!) When extra ingredients are added to your recipe you need to account for the amount of leavening agent still needed to help your cupcakes rise stably. Failing to do so would lead to sinking cupcakes. 

How to Fix It: Baking is a science! Try not to improvise too much and follow the recipe for more predictable results.

FAQs

Here are some other questions you might have about cupcakes, I’ll answer them below.

How do you keep cupcakes from sinking?

You can prevent your cupcakes from sinking by going over the above tips – making sure that your leavening agent is potent, that you’ve set your oven temperature correctly, not overmix the batter, not overfilling liners, and simply follow the recipes given without making too many changes.

Should cupcakes be flat or domed?

The ideal cupcake is one that’s in between flat and domed. You want a cupcake top that is evenly raised but without a pointy hardened center. 

Can you eat sunken cupcakes?

Generally speaking, sunken cupcakes are still good to eat as long as they’re fully cooked through. You should know if a cupcake is completely cooked through by performing a toothpick test on it before taking it out of the oven. 

Final Thoughts

Finding sunken cupcakes can be disappointing, but don’t worry, they will still taste just as good and you can use them to make cake pops. What’s more important is that you remember the above tips so that next time you won’t make the same mistake again. 

Have you ever baked sunken cupcakes? If so, what did you end up doing with them? What have you done since to prevent it from happening again? Let us know in the comments!

I am a self-taught baker. I’ve been baking for over 10 years and started my own home baking business as a side hustle. I was born in Hong Kong and spent a pretty big chunk of my life in Canada. If you’re ever looking for me, I am probably there whisking vigorously away in the kitchen.