Thermos flasks keep tea, coffee and other drinks hot for a long time.
They are available in different materials, with different closures and insulated containers.
AllesBeste looked at 15 models and explained how the jugs differ.
Thermos flasks are designed in such a way that the heat transfer to the environment is as low as possible.
The outer shell is usually made of stainless steel or plastic, the insulating vessel inside is made of glass or stainless steel.
Although glass has better insulating properties, it is not as break-proof as stainless steel.
It can happen that the inner vessel shatters and glass splinters get into the drink.
There is a vacuum layer between the outer shell and the insulating vessel, which prevents the conduction of heat.
As a result, there is almost no heat exchange with the environment, so that the drinks in the jug stay hot for a long time.
In many models, the inner vessel is also mirrored, so that the heat is reflected into the drink, which enhances the temperature-maintaining effect.
Thermos flasks are available with different capacities and different closures.
Classic thermos flasks usually have a twist or pressure cap.
Screw caps have to be opened slightly for pouring, so that operation is not possible with one hand.
There are two different versions of pressure closures: Either the lid has a central push button that has to be pressed to pour.
Or the lid has a lever on the side that is pressed down when pouring.
Operation with one hand is possible here.
Thermos in the test
The test portal AllesBeste has tested 15 thermos flasks.
The test winner is the Emsa vacuum jug.
Thanks to the soft-grip handle, it lies very comfortably in the hand and can be conveniently operated with one hand thanks to the pressure lock with lever.
The model can also convince in terms of thermal insulation.
The vacuum jug is available in four different colors and at a fair price.
Another recommendation is the Behövd from Ikea: The tall, mint green thermos not only looks good, but also delivers the second best values in the test in terms of thermal insulation.
The disadvantage is that the lid has to be opened for pouring, so that operation is not possible with one hand.
However, the model is available at an unbeatable price.
More information and other recommended alternatives can be found in the detailed review by AllesBeste.