Can you put a thermos in the microwave? The benefits of using a thermos

Can you put a thermos in the microwave? The answer, of course, is yes. You can also use a thermos to store food and keep it warm. Here are some of the benefits of using a thermos for your food and the answer to “Can you put a thermos in the microwave?”

What is a thermos, and how does it work


A thermos is a container that keeps food hot or cold by using vacuum insulation to trap the temperature of the foods inside. It contains a hollow space that traps heat in an isolated area from the rest of the environment, thus preventing heat transfer into or out of the insulated space.

A simple thermos consists of two flasks, one placed within another. The gap between the two flasks is usually filled with insulating materials such as foam, which creates a barrier for conduction and convection. This means that heat can only pass through by radiation, which maintains even temperature distribution throughout its contents. A simple vacuum flask (called ‘vacuum bottle’ or ‘vacuum flask’) works two.

Can you put a thermos in the microwave?

Yes, you can put your vacuum-insulated container or Thermos in the microwave. The microwaves from the machine will not harm the Thermos as it is designed to insulate and maintain their temperature inside. Some thermoses have containers for both hot and cold food inside them so that you can use them as a food warmer too.

BUT, this is not recommended as it can damage your Thermos. A microwavable container is best used to heat foods already cooked or pre-cooked. You cannot use it for cooking food inside or reheating uncooked foods because microwaves are high-energy waves, which means they vibrate at very high frequencies. This could impact how your food tastes after heating up when using microwavable containers with insulating properties.

Read more: Can you microwave pyrex? Answers and explanations

Why use a thermos for food storage

 There are many reasons why people use Thermos for their food storage. It allows people to prepare their meals ahead of time, store them easily and eat whenever they want without having to reheat all over again. 

One reason is that most foods require reheating. Instead of eating cold or lukewarm food, you can use your Thermos to keep the food warm until you are ready to eat it. Some people use thermoses instead of microwaves because they can reheat their meals slowly and evenly.

How to clean your Thermos after using it for hot or cold liquids

clean your Thermos
clean your Thermos

After using a Thermos for either hot or cold liquids, wash the parts that have come into contact with oils, juices, milk, etc. For all-purpose cleaning, scrub any part of the inner flask with soap and water before allowing it to dry completely. Do not put anything metal inside the container as this will scratch the surface. If any unpleasant smells are coming from your container, it is best to use a vinegar solution or soap with baking soda.

Where can I buy a good quality Thermos that will last me years to come?

You can buy some of the best thermoses for cheap at You can choose from a wide range of brands and styles depending on your preferences. Whether you want a collapsible type or a vacuum insulated one, you can find them all on Thermoses also make great gifts for your loved ones, whether teenagers or adults who work outside the home. Look through our list of the best-selling stainless steel lunch boxes, and you’ll surely find something perfect for everyone in your life!


If you would like to heat your Thermos in the microwave, here are some instructions on how to do so:

1. Make sure that your Thermos is completely dry before microwaving it. Any moisture inside the container can cause the Thermos to burst.

2. Open the lid of your Thermos and remove the food inside.

3. Place the food inside a microwavable dish and cook it according to its recommended time and temperature.

4. Once the food is cooked, place it back inside the Thermos and replace the lid.

5. Heat your Thermos in the microwave for 2-3 minutes on high power or until the food is warm.

6. Allow the food and Thermos to cool for a few minutes before eating your meal.

7. Store leftovers in an airtight container and cut back on reheating your meals next time you need something to eat.

8. If any unpleasant smells are coming from your Thermos, it is best to use a vinegar solution or soap with baking soda.

Read more: Do Rice Cakes Go Bad? Who Shouldn’t Eat Rice Cakes?

Thermos FAQ

Is it okay to drink from an older thermos?

When it comes to drinking from an old thermos, the consensus is that it is not safe. This is because the older the Thermos, the more likely it is to have cracks and other damage that could cause harmful chemicals and toxins to leach into your drink. If you have an old thermos that you still want to use, it is best to boil some water and pour it inside the container before letting it cool. This will help kill any bacteria or mold that might be growing inside.

Is it possible to fill a thermos flask with boiling water?

It is not recommended that you put boiling water in a thermos flask as it can cause the container to burst. If you need to heat up your food or beverage, it is best to do so using a microwave.

Is it possible for coffee to go bad in a Thermos?

Coffee can last for a few days in a thermos. If you’re not going to drink it right away, make sure to put it in an airtight container. This will prevent it from absorbing other flavors and odors.

If you leave your coffee inside the Thermos for too long, it might end up tasting like whatever food or liquid was in there before. You can avoid this by putting fresh coffee in your Thermos every day.


Do you think a thermos could be used in the microwave? Of course, you may. You may also use a thermos to keep food warm. Here are some of the advantages of utilizing a thermos for your meals, as well as the answer to “Can you put a thermos in the microwave?”

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Written By Bourbon O

I have been an artist and journalist for many years. I am a food blogger who is crazy about food, drink and specially kitchen gadgets.

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