Best thermos test

In this review, we will compare three premium thermoses from three legendary brands. They stand out with their high quality, excellent heat resistance and extreme durability, which make them great allies for an active lifestyle.

Imagine a fabulous holiday in the Swiss Alps, enjoying skiing with your friends. Or a boat trip on the river with your family. It is difficult to imagine being outdoors without a quality thermos. A warm cup of tea or coffee can enhance any moment spent outside.

In this review we will compare three premium thermoses from three legendary brands. They stand out with their high quality, excellent heat resistance and extreme durability.

Let’s find out which of these thermoses will be the best one:

  • Thermos Stainless King 1.2L
  • Stanley The Legendary Classic 1L
  • Esbit Vacuum Flask 1.5L

We have thoroughly tested a variety of factors, including thermal resistance, practicality, ease of use and value for money. Here are some of the best brands for Thermoses.

Thermos brand

Content of the following article

Why did we choose these thermoses?

If you spend a lot of time outdoors, relaxing for hours or working in the open air, you might need a thermos. In order to be able to warm up with tea all day long, or on the contrary – cool down with cool water – a high-quality thermos will be your best friend.

A good thermos must have an extremely high thermal resistance, an easy-to-use handle, a cup and a pouring mechanism. It is just as important that it has a high quality exterior, so it won’t break so easily when dropped.

We were looking for the best thermos in the 40-50 EUR range. We think we have found some very good options. Check them out below!

Thermos Stainless King 1.2L

Thermos Stainless King

Of course, the best start in the search for the thermos is the company that is literally named after the product – Thermos. They are the ones who created the world’s first thermos in the first place. The brand’s thermoses have been known for their high quality thermoses since 1904. And the Stainless King 1.2L is no exception.

Its design combines modern trends with classic charm. Stainless King Thermos’s redicted thermal resistance is 24 hours, although our tests even exceeded this figure.

Stanley The Legendary Classic 1L

Stanley The Legendary Classic

Stanley’s thermos brand is younger than nine years, however the quality of their products is equally impressive. Military green thermoses, thermo mugs and water bottles of Stanley have been one of many people’s first choices since 1913. They’re the best for hiking, hunting, extreme adventures and other outdoor activities.

Although Stanley products are available today in a variety of colors, we have traditionally chosen The Legendary Classic 1L thermos in green. It stands out with its predicted 24-hour thermal resistance and high quality.

Esbit Vacuum Flask 1.5L

Esbit Vacuum Flask

Esbit thermoses are also familiar to hiking enthusiasts since they invented pocket-sized cookers. Later, using its expertise in the production of heat-resistant dishes, Esbit also focused on the production of thermoses.

In this price range, Esbit offers the largest capacity, state-of-the-art design and the most advanced features. It will be particularly interesting to compare how it competes with its main competitors mentioned above.

Thermos design

In terms of function these thermoses are designed for the same scenarios – hiking, active lifestyle, outdoor work. Yet it is surprising how different these thermoses can be. 

Each of them represent a completely different design philosophy. In addition to their own taste, each has its own pros and cons.

Thermos Stainless King 1.2L design

design thermos

The first thermos is designed in a classic style. All the way from the glossy retro printing logo to its very traditional shape. 

The Thermos Stainless King 1.2L is a vacuum-insulated beverage bottle that can keep your favorite beverages hot or cold for up to 24 hours. It has a built-in serving cup that doubles as a lid and a twist-and-pour stopper feature that makes pouring easy and ensures a tight seal. The bottle has a large capacity of 40 ounces (1.2 liters), making it perfect for serving the whole family. It is made of stainless steel, which makes it durable and long-lasting.

In reality, this thermos looks impressive because of its 18/8 stainless steel shiny and glossy surface. It is true that fashion has sacrifices. If you take this thermos with you on more extreme adventures, you will face scratches – especially on its base.

The thermos handle is made of high-quality materials – thick and solid plastic, thick metal parts and a high-quality connection to the body. In view of this, we did not like to use this handle. It has a very large free movement, and it does not fit snugly into the body of the thermos when it is assembled.

Lifting the Stainless King by the handle, it moves and your fingers still touch the thermos itself. That makes you feel the cool steel caress. It also makes a lot of noise when carried in a bag.

All in all, the Thermos Stainless King is a quality product. Its elegant design will fit into both a glamping (glamor camping) holiday and an extreme mountain climbing adventure. Of course, if you like that your things stay as shiny and flawless as on the first day, you will want to watch out for scratches. Otherwise it combines great style with practicality.

Stanley The Legendary Classic 1L design

design thermos

On the other side of the spectrum – here is a complete triumph over appearance, the Stanley thermos. This thermos is designed in military green with a rough-textured surface. Compared to other competitors, this thermos is narrower and longer. Stanley has deliberately chosen this shape, arguing that it is more comfortable to hold with one hand. 

The Stanley The Legendary Classic 1L is a vacuum-insulated bottle that can keep your favorite beverages hot or cold for up to 24 hours. It has a leak-resistant lid that can be put in your backpack without worrying about spills. The bottle has a large capacity of 1 liter, making it perfect for serving the whole family. It is made of high-quality food-grade stainless steel, which makes it rugged and rust-proof.

It is also made of 18/8 stainless steel. This Stanley thermos is designed for an extreme lifestyle. Both after the first impressions and a month after use, it can be concluded that it will withstand the test of time. Nor can we forget about Stanley’s lifetime warranty. It promises to replace the product unconditionally if it doesn’t live up to its promise.

The handle of the Stanley The Legendary Classic has significantly less freedom of movement than the Thermos. It is making it more comfortable to hold the thermos in your hand. The handle itself is high-quality, with a matte plastic exterior and a rubberized grip. 

Stanley The Legendary Classic gives the impression of a very durable thermos in terms of both appearance and feel. Esbit Vacuum Flask 1.5L design

Esbit Vacuum Flask 1.5L design

design thermos

This Esbit thermos is truly grandiose, especially in its diameter. Of course, there is a good reason for this – it stands out among the thermoses tested with the largest volume. Its body is made of 18/8 stainless steel with a rough, matte black surface. It is complemented by inconspicuous orange colored elements.

The Esbit Vacuum Flask 1.5L is a vacuum-insulated flask that can keep your favorite beverages hot or cold for a particularly long time. The flask has a slim-line shape that makes it easy to store and comes with a non-slip rubber pad that ensures a secure stand and protects the food jug and storage area. The combined screw and pouring top is 100% leak-proof, and the lid in double-walled stainless steel can be used as a cup, about 170 ml.

Among these three, Esbit has a soft plasma base with loops to cover the shoulder strap. This is an additional way to hold this thermos. The handle itself is the most modern solution among the three– it is made of rough plastic, and thanks to its well-thought-out mechanism, it can be easily folded. That way it fits completely into the body of the thermos. 

While some may have concerns about the sustainability of such a complex mechanism, this handle seemed firm and strong during our test.

Of course, there are many followers of the classic values, but there is no denying that Esbit’s innovations make it the most practical everyday thermos among the three. It also stands out with its impressive lid functionality and two whole cups.

Let’s first make a direct comparison between these three thermoses in numbers.

thermos compared

Drinking cap

If you carry your thermos in a backpack, in the trunk of a car or in any other way, it is important that the lid closes the thermos completely securely and protects it from leaks. In our tests, we concluded that all three thermoses are completely safe from leaks, and the drink never spilled when carried in a backpack.

Both Thermos and Stanley have chosen a proven design – a simple screw cap with small gaps for the drink. When completely closed, the cap makes sure the container prevents the beverage from spilling. However when it is unscrewed in half, the drink can be easily poured into a cup without opening the container completely. It’s an ingeniously simple solution.

thermos caps

Here, too, Esbit has chosen to be different with a modern push-button solution. By pressing the bright orange button in the very center of the lid, you will be able to pour the drink. On the one hand, it is a convenient solution that allows you to fill your cup with just one hand. On the other hand, it is more difficult to clean. 

We also noticed that there may be some liquid left in the gap after pouring the drink. Therefore, when using Esbit Vacuum Flask, you will have to learn a new ritual – make sure you have completely poured everything into a cup. It is also important to note that due to the large lid, the diameter of the thermos neck is significantly larger, which makes it easier to clean the tank.

Since all these caps faithfully perform their basic function, the only factor in choosing the right cap is your own taste. Some will appreciate the classic and simple Stanley and Esbit mechanism, while others will enjoy the ease of use provided by Esbit. Each has its pros and cons.

Drinking cup

drinking cups thermos

You can’t just sip a drink from a thermos like from water bottles – you have to pour tea or coffee into a smaller cup. That’s why a cup is just as important as a thermos. All three thermoses are endowed with a high-quality stainless steel cup, which is insulated inside with a plastic wall.

The Thermos cup stands out from the outside with a polished steel surface, which, combined with its black and glossy body, creates a completely elegant impression. It has a black plastic inner wall. The volume of the cup is 200 ml and its shape is convenient to drink from. However, it must be concluded that when hot tea is poured into a cup, it heats up thoroughly, which can make holding the cup in your hand uncomfortable.

The Stanley cup, on the other hand, is narrower and longer and has the same volume of 200ml. The cup stands out from the outside with its steel texture, but inside it is covered with a green plastic wall. Although it is still noticeably warmer than the Thermos cup, it was more pleasant to hold in your hand after pouring boiling tea.

The best insulation was for the Esbit cup, which, like everything in this thermos, was grandiose. It stands out with a huge diameter and the largest volume of 250ml. Its exterior is made of the same matt black steel as the body, while the inside is made of orange plastic. 

Esbit doesn’t stop surprising, and in addition to the big cup, they have also included a small 135ml plastic cup. It is not as durable as the large mug, but if you do not go hiking alone and want to share warm tea, it can be useful. It seemed strange to us that the other cup is not fixed anywhere – it is simply placed on the thermos before screwing on the big cup. As a result, it often fell when the thermos was unscrewed immediately.

Thermal endurance test

The most important factor in choosing a thermos is its ability to keep the drink hot (or cold) throughout the hike or work day. All three thermoses promise that the tea or coffee will stay hot for 24 hours. Since we do not know their methodology – how hot the water was poured, how many degrees are considered ‘hot’, in what environment they are tested – we took the measurements ourselves.

These thermoses use double-walled vacuum technology, which is one of the best construction methods for thermal insulation vessels. This means that the thermos has an outer wall and an inner wall between which there is a vacuum. Because there are no molecules in the vacuum that can heat up and conduct heat, most premium thermoses.

thermos endurance
Photo taken from Thermos homepage


To test the ability of these thermoses to keep the drink warm, we first boiled water (97 ° C) and filled it into each of the thermoses to their maximum capacity. The thermoses were stored at room temperature (19 ° C) and temporarily opened every 4 hours to measure the temperature of the drink.


In the first four hours, all three thermoses were quite similar, but by the eighth hour, Thermos took the lead. In turn, the weakest thermal resistance between the three is for the Esbit thermos. This could be explained by the cap, which has exchanged maximum insulation for ease of use.

When we make reviews, we assume that a drink is considered hot if its temperature exceeds 60 degrees. By measuring this criteria, it can be said that Thermos and Stanley have kept their promise – 24 hours. Esbit, on the other hand, slipped below 60 degrees shortly before the end of the day, which is 2 degrees different from what was promised.

Thermos Stainless King 1.2L kept the drink hot for the longest time, followed by Stanley. Although Esbit has cooled the fastest compared to both competitors, this thermal stability is still respectable. All three thermoses will keep the drink warm even on the longest hikes. After all – if the thermos is full of delicious tea or coffee, it is usually drunk in less than 24 hours.

test thermos

After 48 hours, we took the measurements again for interest. The results at 48 hours after injection were: Thermos: 53 ° C, Stanley: 47 ° C, Esbit: 40 ° C. The winner of the heat resistance competition is undoubtedly Thermos Stainless King 1.2L, which is perhaps not surprising. After all, this brand has more than 110 years of experience in the production of heat-resistant products.

Which is the best thermos?

Each thermos has its own pros and cons, which makes each more suitable for a particular taste and needs. If you are looking for a new companion for active lifestyle, everyday life or work, each of these three thermoses will be a great choice. They will also be a great gift for a friend, colleague or a loved one. Also, check out the best thermoses for a lifetime.

best thermos

For example, the best everyday thermos is the Thermos Stainless King 1.2L. Its sleek and compact design makes it a great companion for all situations, and its unrivaled thermal resistance will never leave you with a cold cup of coffee or tea. The main disadvantages of this are the body paint, which is very easy to scratch. If you want it to look perfect, you will have to avoid extreme activities.

However, for fans of extreme activities, the best choice will be the Stanley The Legendary Classic 1L. It leaves no doubt about its durability. It’s just as good of a choice to take it to the trip to music festivals and a trip to Everest – Stanley will survive. Good thermal resistance, functional design and legendary reliability are worth the price.

Finally, the Esbit Vacuum Flask 1.5L. We liked various useful things, such as the easy-to-fold handle, two cups, the push-button lid and the plastic base, which makes using this thermos very convenient. Although the thermal resistance of this thermos was weaker than that of the other two, most of the modern advanced features of this thermos are worth a few degrees of difference.

pros and cons of thermoses

We hope this thermos test was interesting and useful to you! Let us know what you think – do you have any of these thermoses?

Meanwhile check out our review of the Stanley thermos – Stanley Thermos: review. Review of Thermos Traveler and Stanley travel mugs.