There are many reasons why your brownies may be boiling in the oven. One common cause is over-mixing the batter, which can introduce too much air and create bubbles that rise to the surface during baking. A high oven temperature or incorrect measurements, can also lead to boiling brownies.
In this article, we’ll explore the various reasons why brownies boil in the oven and provide tips on how to avoid this frustrating problem.

What causes brownies to boil
Check out the top reasons why brownies are boiling in the oven.
1. High oven temperatures
One of the most common causes of boiling brownies is a high oven temperature. When the oven temperature is too high, the edges of the brownies cook too quickly, and the middle can’t keep up. As a result, the brownies boil and bubble.
To fix this, turn the oven down by 25 degrees. This will help the brownies to cook evenly and stop them from boiling in the middle.
2. Overmixing the batter
Overmixing the batter can also cause brownies to boil. When you overmix the batter, you introduce too much air into it, which can cause the air to be released when it heats and boil. To avoid this, mix the batter until it’s just combined.

3. Incorrect pan size
Choosing the wrong pan size can also cause boiling brownies. If the pan is too small, the batter will be too thick, and the brownies will boil and bubble. On the other hand, if the pan is too large, the batter will be too thin, and the brownies will overcook.
To avoid this, choose the right pan size as per the recipe to ensure proper brownie thickness and baking time for the best results. Most brownie recipe work well in an 8×8 inch square brownie tin.
4. Oven hot spots
Another possible cause of boiling brownies is oven hot spots. If your oven has hot spots, some parts of the brownies will cook faster than others, causing boiling and bubbling. To fix this, rotate the pan halfway through the baking time to ensure even cooking.
Boiling brownies can be caused by several factors, including high oven temperature, overmixing the batter, incorrect pan size, and oven hot spots. By understanding these possible causes, you can fix the problem and enjoy perfectly baked brownies every time.
How to stop brownies from boiling in the oven
To prevent brownies from boiling in the oven, there are several key steps you can take to ensure they bake evenly and come out perfectly every time.
1. Preheating
One of the most important steps in baking brownies is to preheat your oven to the correct temperature. This will ensure that your brownies cook evenly and don’t boil or bubble in the oven.
Always preheat your oven for at least 15 minutes before baking, and use an oven thermometer to ensure that the temperature is accurate.

2. Use an oven thermometer
Using an oven thermometer is essential for baking perfect brownies. Many ovens are not calibrated correctly, so the temperature on the dial may not be accurate.
An oven thermometer will give you an accurate reading of the temperature inside your oven, so you can adjust the temperature as needed to ensure your brownies bake evenly.
3. Use the right baking dish
Choosing the right baking dish is also important when baking brownies. A metal or glass baking dish is best, as it will conduct heat evenly and help your brownies bake evenly. Avoid using a dark, non-stick baking dish, as this can cause your brownies to cook too quickly and become dry or burned on the edges.
4. Mix the ingredients properly
When mixing the ingredients for your brownies, be sure to follow the recipe carefully and mix the ingredients together just until they are combined. Overmixing can introduce too much air into the batter, which can cause your brownies to boil or bubble in the oven. Use a spatula to gently fold the ingredients together, and avoid using a whisk or electric mixer.
By following these simple steps, you can prevent your brownies from boiling or bubbling in the oven and ensure that they come out perfectly every time.

Conclusion
Ihere are several reasons why brownies may boil in the oven. The most common reasons include overmixing the batter, incorrect oven temperature, overbaking or underbaking, using the wrong pan size, and incorporating too much air into the batter during the mixing process.
To avoid these issues, it is important to follow the recipe instructions carefully, use the appropriate pan size, and ensure that the oven temperature is accurate. It is also essential to mix the batter gently and avoid overmixing or incorporating too much air.
If your brownies still boil in the oven despite taking these precautions, it may be worth investing in an oven thermometer to ensure that the temperature is accurate. You can try adjusting the oven temperature slightly or experimenting with different pan sizes and types to find the best fit for your brownie recipe.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.