Insulated food flasks are great for hiking trips, where you have no place to heat meals, but they are also great for offices or schools.

We have tested the best food flasks, they can keep your food warm or refrigerated for hours without you worrying about spilling. 7 Image source: Getty

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One of the first things to consider when choosing the best food flask for you is the size.

For children, there is a smaller capacity of about 300 ml. These are not that heavy, can fit in a lunch box, and since children usually eat less, nothing is wasted.

You can also buy a larger capacity of over 800ml, which may be suitable for a very hungry person or a light lunch for two.

Next, consider how long you need to keep the food warm. Look for products that can retain calories for at least six hours.

Things that keep your food warm for longer usually cost more, but they can also be more versatile.

You can also get a flask with collapsible cutlery, which will be convenient when you travel.

Finally, think about how easy it is to clean. Some flasks can be washed in the dishwasher, but hand washing is almost always better. Therefore, a flask with a wider opening is usually better.

We tested some of the most popular brands-this is our conclusion.

The 530ml SHO insulated food flask is one of the larger food flasks we have tried, but you can get a larger 800ml version.

The jar has an external screw cap and an internal screw top cap.

You will get a foldable spoon with this food bottle, which is stored on the top of the inner lid. The inner lid also has a secret compartment under the spoon, which can be used to store salt and pepper when needed.

Outside, you have a convenient strap, so you can easily pick it up and take it with you.

SHO promises to keep your food warm for 10 hours or refrigerate for 20 hours, and it fulfills its promise to us. For hot food, the temperature drops significantly after 10 hours, but it is still hot enough to be eaten without reheating.

What we particularly like about this color is that it has a variety of colors to choose from, which means it's easy to get the shade you like.

Zwilling's low-key food bottle is only available in one color-white base and gray lid-it looks and feels like a food can for adults.

Inside the gray lid, you will find a second screw lid with a foldable spoon inside. Hidden beneath it is a beautiful button that you can press to release the vacuum seal in the container, making it easier to unscrew.

The double-layer insulated internal design can keep food warm for up to 8 hours or refrigerate for 11 hours.

In testing, we found that this helps keep the contents of the jar warm. We particularly appreciate the quick release button, which makes it easier to unscrew the jar.

Another feature we like is that the jar has a wider opening, which makes it easier to clean afterwards.

The Hydro Flask insulated food jar is one of the simplest designs we have tried. The 28 oz (828 ml) version has a large capacity. However, you can also get a smaller 20 oz (591 ml) version.

The cylindrical jar has a wide bottom with a lid, and the lid is covered with a grip material to make it easier to unscrew.

This one has no inner lid or utensils, nor does it promise to keep your food warm or cold for a specific period of time. Therefore, we decided to keep it warm for at least 6 hours.

During the test, we found that the contents of the jar had cooled significantly at the end of 6 hours. It still feels hot to the touch, but you may want to reheat it based on what you have stored.

We don't think this is a big problem, but obviously it depends on how long you need to keep your food warm. This is not ideal for a camping trip where you may not eat for a few hours, but for an office, the holding time should be sufficient.

One feature of this jar is its large opening, which makes adding food and subsequent cleaning easier.

This Contigo food jar is specially designed for children with interesting marine-themed patterns.

The design is quite simple, with a sealed screw cap and cylindrical base. There are grip grooves on the lid, which helps smaller hands to open the jar.

However, it has a smaller capacity, with a capacity of only 300 ml, so depending on your child's hunger level, it may be only part of a meal, not the whole.

Tableware is not included, so you must remember to pack some.

In the test, we found that the jar fulfilled its promise of keeping our food warm for 6 hours and refrigerated for 7 hours.

Its compact size means it is really easy to fit into a lunch bag, and we don’t have to worry about overflow.

It is also easy to clean, although the base is not dishwasher safe.

Thermos is the most famous brand for making thermos, so they attribute it to an art.

We tried the 470 ml version, which is just suitable for one person.

It is light and compact, with insulated walls, which can keep your food warm for 9 hours or refrigerated for 14 hours.

You will get an outer lid that doubles as a cup, while the inner lid is sealed for waterproofing and insulation. The inner lid also contains a foldable spoon, so you can take everything you need with you.

This food flask is one of the most affordable sizes, and we especially like its light weight. It also did a good job of keeping food warm for a full 9 hours.

The only disadvantage we found is that compared to some other options, the taper of the opening is larger, which means that cleaning is not that simple.

The Black + Blum food flask uses a stylish stainless steel design with a nylon strap to fix the natural wooden spoon while adding popular colors.

It has a capacity of 400 ml, which is perfect for a person-but if you are extremely hungry, you need some extra sides.

The leak-proof design also promises to keep your food warm for up to 6 hours or refrigerated for up to 8 hours.

When we tested this flask, it kept the contents piping hot until we were ready to enjoy it, and the slender frame meant it could be easily stored in our lunch bag or carried with us.

However, the silky smooth stainless steel surface makes it more difficult to tighten and loosen the lid. On the bright side, this makes it very easy to clean it-because it cannot be placed in the dishwasher, it is very convenient.

We must also wrap the spoon to make sure it stays clean before use because it is on the outside of the flask instead of inside.

Among the food flasks we tested, we think the Thermos stainless steel King food flask is the most suitable for soup.

Not only is it affordable, but it also keeps the contents hot for several hours.

In addition, the conical top of the flask means it is easier to drink-of course you can also use a foldable spoon.

There are several different ways to keep the contents of a thermos warm, starting with a double-layer base.

Sandwiched between the inner and outer layers is a gap-this vacuum prevents heat from reaching the outer layer, because heat can only be conducted through particles, whether in the air, through liquids or solids.

The thermos also has a sealed screw top cap to help prevent heat from escaping through the opening.

Obviously, heat may still be dissipated from the junction and seal of the two layers, which is why even the best thermos will eventually dissipate heat.

The price of thermos flasks depends on their size and holding time.

The range ranges from approximately £20 to £40, but most are around £30.

Food bottles can be seen everywhere on the Internet, especially outdoor experts.

In addition to the ones we introduced above, you can also find plenty of options on Amazon or Argos.

Some flasks can be washed in a dishwasher, which makes cleaning very easy, but if possible, it is best to wash by hand.

For beverage bottles, you need a slender brush that can reach the bottom, while for shorter food bottles with wider openings, you can usually clean them like cups.

For any stains or unpleasant odors, just add a few teaspoons of sodium bicarbonate to the flask and then pour hot water.

Make sure you do this slowly, as it can easily overflow.

Then you only need to leave the liquid in it to work for half an hour, and then rinse it off.

If you use a flask to store hot water, you may see scale buildup.

To remove it, just add a few tablespoons of white vinegar to the flask and then add water. Leave it for a few hours or overnight to give it time to work.

Before rinsing, just quickly clean with a bottle brush to remove any stubborn deposits.

Find more of our product summary to help you fully enjoy the outdoor activities here.

We also have a camping guide.

In order to enjoy the best view, here are some camping chairs that you can use during your next outdoor rest.

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