While the taste of zucchini bread isn’t going to change just because the middle part sank, the presentation is less than ideal. It isn’t something you’d want to give someone.
This begs the question: Why does my zucchini bread sink in the middle?
In this article, we’ll investigate the different causes of this problem and take a look at how you can fix it.
Let’s dive in!
Why Does Zucchini Bread Sink in the Middle?
There are five main reasons why zucchini bread collapses. Either:
- The pan is overfilled.
- The ingredients were mixed improperly.
- Your oven’s settings run differently.
- You have a bad pan.
- The leavening agents are either excessive or expired.
Below, we discuss each cause in depth!
1 – The Pan Is Overfilled

One common reason why zucchini bread and other types of quick bread tend to collapse is that the pan is overfilled. If the baking batter reaches the highest point of the pan and still needs to expand, it will collapse.
The batter needs the pan sides to be able to keep its structure. As such, you should fill the pan by 2/3rds at most to prevent the batter from collapsing in the middle.
2 – Improper Mixing
It comes without saying that the ingredients of zucchini bread have to be properly mixed to get a good finished product. If you mix the batter too fast or too vigorously before putting it in the pan, you could end up with unstable air bubbles inside.
As the bread cooks, the air bubbles will cause it to rise and then quickly collapse.
To prevent this, we recommend that you mix ingredients with a gentler touch. If you’re using an electric mixer, set it to medium speed, not high.
When adding eggs, put them in one at a time. Mix the ingredients in between each addition.
If you’re mixing by hand, combine the ingredients gently. Both of these methods of mixing will ensure that sufficient gluten forms, resulting in a stable texture.
3 – Oven Settings and Temperature

Another reason you might want to reconsider is the oven temperature and settings. Some ovens run at a colder temperature than others, others go higher than they should.
If the oven isn’t building to a consistent temperature while baking, the zucchini bread will probably collapse in the middle.
Because of this, you should use the oven’s thermometer to approximate the oven’s accuracy. We recommend that you wait for about 10 minutes after the oven beeps, as that tells you that the preheating is done.
After that, you can put the batter inside to bake.
Secondly, make sure you don’t open and close the oven door too often while the bread is baking, as this results in a loss of heat. The bread won’t be thoroughly baked, causing it to sink in the middle.
So, only open the oven door to check on the bread’s readiness. If the oven’s door is transparent, then look through it instead of opening it.
4 – You Have a Bad Pan
When baking quick bread, you have to be careful with what kind of pan you’re using. The best choice is a metal loaf pan, as metal is an efficient conductor of heat.
Because of this, the bread will be baked consistently throughout, preventing it from sinking in the middle. On top of that, you should use lighter-colored pans to avoid browning your bread too much.
However, there may be no option for you other than picking a glass or ceramic pan. In that case, you’ll have to slightly reduce the temperature and increase the baking time by around 10 minutes.
Doing this will ensure that the bread will be baked thoroughly before the edges begin drying out.
Also, make sure to only grease the bottom of the pan. This will ensure that the batter clings to the sides of the pan as it rises and forms the rounded top.
Lastly, use the same size loaf pan as the size dictated by your recipe. You don’t want the ingredients to end up being more or less than the pan is ready to handle!
5 – Expired or Not Enough Leavening Agents

You need to be careful with what leavening agents to use. If you use an expired leavening agent, it will be unable to properly raise the bread.
When this happens, the middle will sink soon after. For this reason, make sure to check the expiration date of the leavening agent that you’re going to use.
In addition, adding excessive amounts of a leavening agent can cause your zucchini bread to sink in the middle. As such, don’t use more or less of what the recipe calls for.
How to Know for Sure That My Zucchini Bread Won’t Sink in the Middle?
To test your zucchini bread, poke it in the middle with a toothpick. It should come out clean.
However, if it doesn’t, or if there appears to be some wet dough at the top of the loaf, extend the baking time by five to ten minutes.
Once finished, check if there’s a crack on top of the zucchini bread. A crack is an indication that steam escaped from inside during baking, which means that the middle isn’t going to sink.
Final Thoughts
The reasons why your zucchini bread sinks in the middle include an overfilled pan and improper mixing of ingredients. You may also have an inconsistent oven temperature, a bad pan, or expired/too much leavening agent.
To know for sure that your zucchini bread won’t sink in the middle, you may poke a toothpick through its middle or look for a crack on top of the loaf.
Sarah is the founder of Baking Kneads, LLC, a blog sharing guides, tips, and recipes for those learning how to bake. Growing up as the daughter of a baker, she spent much of her childhood learning the basics in a local bakery.