Why Did My Soup Explode in the Microwave? (Explained)

Categorized as Microwave Cooking
why did my soup explode in microwave

We all love our microwaves, and we couldn’t live without them. They’re great for heating up leftovers or even cooking a meal from scratch! However, what do you do when something goes wrong? A common problem that most people have experienced is the explosion of the soup inside the microwave oven.

Why Did My Soup Explode in the Microwave?

Soup explodes in the microwave when it is heated unevenly. This can happen when a liquid doesn’t heat evenly in the microwave, causing it to build up steam pressure in one area. The soup will inevitably explode when the pressure is too great.

Here’s a short guide on how to microwave soup:

Put the soup in a microwave-safe dish and cover it with a microwave-safe cover. Reheat for approximately two to three minutes. Stir every 30 seconds. When thoroughly heated, carefully remove the soup from the microwave and let it cool enough to eat.

What is Superheat?

Let me explain a bit more.

Microwave works by emitting waves of electromagnetic energy. This type of energy is able to penetrate the food more deeply than other traditional cooking methods, such as the oven.

Although this method allows the user to heat up any food quickly, it does have some drawbacks. The major downfall of microwaving food is that it does not allow even cooking, especially with foods that have a high water content, such as soup.

The microwaves emitted from the microwave oven cause the molecules within your food to vibrate and heat up, but since soup tends to be relatively viscous, all of the molecules don’t heat at the same time.

Some areas will become hotter than others and eventually causes steam vapor within the soup to build up and be trapped underneath cooler areas. When the pressure becomes too great to be contained, the soup will eventually explode.

This phenomenon is known as superheating.

For thick foods such as soups and oatmeal, you need to stir them during microwaving frequently. This will help to dissipate the steam and prevent splatters.

Other high water content foods such as an egg or potato may also explode in the microwave. As for these foods, to prevent the internal pressure from becoming too great, they should be pierced with a fork before microwaving.

Why Superheating Is More Likely To Happen in a Microwave

Superheating is a phenomenon that occurs when water or foods with high water content are heated at a temperature higher than the boiling point without boiling. But, when we heat water on a stovetop, we can easily see bubbles starting to form and steam rising from the surface of the water.

Why doesn’t the same thing happen when we heat water in our microwave ovens?

This happens because a microwave works by passing through the container and heating the liquid directly. In other words, during the process of microwaving, the liquid absorbs a lot of energy, but the container itself does not.

As a result, some parts of the liquid will reach boiling point faster than others. It can be faster than it can turn into vapor, causing this boiling liquid to get trapped underneath the cooler areas. These trapped molecules get superheated and become unstable.

When you remove the liquid from the microwave, you disturb it and cause these superheated molecules to vaporize rapidly. This makes it seem like the liquid is exploding, as all of the pressure is released at once.

Furthermore, this problem can be worsened if you use a brand new microwave container with a very smooth surface. Without rough surfaces, bubbles can’t form and therefore can’t release steam.

Is it Dangerous to Reheat Soup in The Microwave?

As weird as it might sound, your soup exploding and splattering all over the inside of your microwave is actually the least dangerous thing about microwaving soup. There were few cases where people suffered burns because the contents of the microwaved soup “exploded” right after they took the soups out of the microwave.

Luckily, this condition is relatively rare. Unless your container is brand-spanking-new, it is likely to have scratches on it.

How Long Should I Microwave Soup?

Technically, a bowl of soup should be heated for approximately 2-3 minutes, stopping every 60 seconds to stir the soup. This is to help prevent those unwanted hot spots.

How Do You Keep Soup from Exploding in the Microwave?

Soup is actually the perfect food for reheating in the microwave since soup does not have any crispy parts to it.

In reality, you don’t have to worry about it getting exploded. This condition is relatively rare and can be prevented easily by following these two simple tips.

  • First, it is advisable to place a wooden spoon in the cup when microwaving your soup. This will help to prevent superheating as its rough surface will help bubbles form.
  • Second, it is recommended to stop microwaving your soup every 30 seconds or so to give it a good stir. Frequent stirring will help prevent hot or cold spots.

It is safe to say that if these two rules are followed, your soup will be just fine in the microwave!

Defrosting Soup in the Microwave

If your soup is frozen, you will need to defrost it first before microwaving. There are several ways to defrost soup. You can thaw it in the microwave or do it the old-fashioned way by thawing it in the refrigerator or under cold running water.

Here are some simple steps you can follow to defrost soup in the microwave.

  1. Place the frozen soup in a microwave-safe container and cover it with a lid.
  2. Open a corner of the lid.
  3. Set your microwave to its defrost setting, and microwave the soup for a minute or two.
  4. Continue defrosting in small intervals, stirring the soup in between.
  5. When the soup is defrosted, microwave the soup according to the reheating instructions.

How to Microwave Soup

Here are step-by-step instructions for heating soup in the microwave:

  1. Prepare a microwave-safe bowl or container for your soup.
  2. Pour your soup into it and cover the top of the bowl with either a plastic wrap or a splatter cover.
  3. Take a wooden spoon and insert it into the soup.
  4. Place the bowl in the microwave and heat on medium for 2-3 minutes.
  5. Check the soup by using a spoon to taste it or using a food thermometer.
  6. Serve and enjoy!

1. Transfer Your Soup to a Microwave-Safe Container

The first thing you need to do is transfer the soup from the can or the carton into a microwave-safe container. Never microwave soup in its original packaging, as these containers are likely not designed to withstand microwave temperatures.

2. Cover With a Plastic Wrap or Splatter Cover

Cover your soup with either a microwave-safe lid or a plastic wrap to prevent splatters from getting all over the inside of your microwave and to encourage even heating. Don’t forget to leave a small opening for steam to escape!

3. Insert a Wooden Spoon Into The Soup

Toss in a wooden spoon into your soup, handle side up. The wooden spoon will prevent superheating by making sure that bubbles and heat don’t get trapped below the surface of the liquid.

4. Heat Your Soup on Medium for 2-3 Minutes

If you are reheating a soup from the can, you may want to first check the package instructions to know how long and at what power level you should heat the soup.

If you’re reheating homemade soup, microwave your soup on medium for approximately 2 to 3 minutes, stopping every 30 seconds to stir. This is another way to prevent superheating and to ensure that your soup is heated evenly.

Related: Reheating Frozen Soup: A Microwave Step-by-Step Tutorial

5. Check for Doneness

The best way to check for doneness is to use a food thermometer. The soup is done when it reaches 165 degrees Fahrenheit. This will make sure your soup is hot enough to kill any bacteria that might have been present in your soup before you microwaved it.

6. Serve and Enjoy!

Bring out your soup carefully using oven mitts, and set it aside for at least one minute to let it cool down.


Microwave is an ideal way to reheat a soup. However, be sure to follow the basic rules to prevent your soup from exploding in the microwave so that you can enjoy it without any harm.

If you’re looking to avoid any potential disasters in the microwave, be sure to check out our other articles on foods that explode in the microwave, such as salmon, butter, and potatoes.

By Rosie Elliott

I’m Rosie. I’m a professional chef with experience in Western, Mediterranean, and Italian cuisine. I’ve been cooking for over 15 years, and I have two daughters that keep me busy!