How Long Do Things Stay Hot In A Thermos?

The thermos is a wonderful invention. They are designed to keep hot and cold things at their perfect temperature for longer than typical containers or cups. With suitable and high-quality thermos, you can prevent your things from getting cold at work or traveling. How long do things stay hot in a thermos?

Some high-quality thermoses will keep your hot drinks hot for up to 24 hours, while the more affordable thermoses will keep your drinks hot for around 12 hours. When it comes to food such as soup, a thermos will keep them hot for the same time, although they won’t always remain safe to consume.

Some things need to be considered when keeping things hot in a thermos. Continue reading with us as we discuss how long something will stay hot in a thermos and what you can do to use your thermos’ abilities to their fullest potential!

How Long Will A Thermos Keep Food And Drinks Hot?

It’s important to know that not all thermoses are manufactured with the same quality of materials. Sometimes, lower-quality materials may mean that a thermos could only keep your food and drinks hot enough to consume for between two and three hours comfortably.

Additionally, suppose you need to keep food hot in a thermos. In that case, the kind of food and how it has been prepared will also significantly impact how long it will remain safe for consumption.

When you’re trying to keep your food, such as soup, or your drink, including coffee or tea, hot, it would be worth following the information provided by the thermos manufacturer.

Some thermoses might require you to take specific steps to ensure your food or drink does not spoil faster than it should.

How Long Can You Keep Hot Drinks In A Thermos?

You can keep hot drinks such as coffee or tea in low-quality thermos for about six hours, and in a premium quality thermos, your coffee will retain its delicious taste and texture for about twelve hours.

The key is temperature retention, and if your thermos keeps your coffee piping hot for hours later, your coffee will still be perfectly safe to consume.

If you have freshly brewed your coffee or tea and poured it into a thermos, you can expect it to stay hot for 12 hours.

However, if your coffee has been sitting in your mug before being poured into a thermos, it may already have lost its taste and accumulated environmental impurities.

If the coffee was covered before being placed in your thermos, you might still be able to drink it, but it won’t have its delicious taste.

How Long Can You Keep Soup In A Thermos?

As we mentioned above, there are some rules you need to follow when you need to determine how long your food will stay safe for consumption in your thermos.

If you are always on the go and have no choice but to store food in your thermos, you need to remember that the bigger your thermos is, the shorter your food will be kept warm.

If you have a wide-necked thermos and keep opening it to expose it to air, it could also play a role in your food spoiling faster. Soup is one of the most common things next to coffee and tea people store in a thermos.

Soup will easily be kept warm for several hours at a time without you having to be concerned that it’s losing its heat.

Sometimes, a typical thermos will keep your piping soup warm for up to seven hours! However, you will need to make sure that the soup is boiling hot and not just warm before pouring it into your thermos.

How To Keep Your Food Hot For Longer In A Thermos

How you prepare, warm, and pack your food in your thermos will inevitably affect how long your contents will stay hot. Furthermore, it would also be an excellent idea to pre-heat your thermos, following the correct steps to get the best results.

Let’s get into how you can get the most heat out of your thermos:

Warm The Contents Before Placing Them Into Your Thermos

If you only have a portion of soup or one cup of coffee or tea for yourself, it means you will have less total heat energy, causing your food to cool down faster.

This is especially true when your thermos isn’t completely filled to its capacity, and there is air inside your thermos. The bigger the volume of your hot soup or hot coffee, the longer the contents will stay hot inside your thermos.

Keep this in mind when warming the contents you want to place inside your thermos. You can either microwave your drink or food or place it on your stovetop until it becomes boiling.

This will help your food or drink to stay hot to the best of your thermos’ abilities.

Wrap Your Thermos In A Towel To Keep The Cold Out

Exposure to cold air or anything cold will cause the contents inside of your thermos to cool down much faster.

One way you can avoid the cold from seeping into your thermos from the outside is by wrapping it in a towel, which will act as insulation, and keep the cold air out and the contents of your thermos as hot as you like it to be!

Wrap Your Thermos In Aluminum Foil

Your thermos has vacuum insulation on its inside, which means it is excellent at stopping two heat transfer types: convection and conduction. However, a thermos is not the greatest at preventing heat loss through infrared or radiant heat.

This is where aluminum foil comes in handy! Aluminum foil is an excellent reflector of heat radiation.

So, if you wrap your thermos in aluminum foil, you will insulate against all three types of heat, which will keep your contents hotter for much longer!


Now that you know how long you can expect your favorite thermos to keep your food and drink warm, you can schedule your lunch breaks accordingly.

If you’re currently using a thermos and you find your contents aren’t staying hot inside these times, it could be an issue with how you prepare them or your thermos. Always read the manufacturer’s rules and how to handle your thermos correctly!


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