Capacity
The nominal volume of a thermos is the maximum amount of contents that it can be guaranteed to contain.
This parameter is directly related to the type (see above). So, a capacity
of up to 500 mL is quite normal for a thermo mug, a flask or a baby thermos, but it is considered small for a classic thermos, and even more so a jug or a thermos for food. The
"500 to 1000 mL" category includes most traditional and food models; for mugs, flasks and children's thermoses, this is actually the maximum volume. Among the jugs there are many more capacious options —
from 1000 to 1500 mL. A volume
of 1500 to 2000 mL is considered quite large, and the most solid models can hold
more than 2 liters.
Anyway, a large volume allows you to hold more drink or food, but the downside of this is an increase in the size, weight and price of the thermos itself. Therefore, when choosing, you should not chase the maximum capacity, but proceed from real needs. For example, a model of 400 – 500 mL is quite enough for two cups of coffee, and for tea drinking at a halt for 3 – 4 people, it is advisable to have a model of at least 1000 mL. More detailed selection recommendations can be found in special sources; especially they will be useful to those who choose a thermos for long-distance hiking trips.
Material
The material from which the body is made is the outer part of the thermos, inside of which the flask is placed.
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Plastic. One of the main advantages of this material is its low cost. In addition, it can be given any colour, and low thermal conductivity contributes to better temperature retention. On the other hand, plastic cases are noticeably inferior to steel cases in terms of strength and reliability, and scratches easily appear on their surface, due to which the product loses its presentation as it wears out. Therefore, plastic is used mainly in inexpensive models of thermoses.
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Stainless steel. Steel is somewhat more expensive than plastic, but much stronger and more reliable. In addition, the steel surface has a stylish appearance that is long-lasting thanks to its scratch resistance. Among the shortcomings of this material, in addition to the price, high thermal conductivity can be noted; manufacturers usually compensate for this moment with various tricks that further increase the price. Nevertheless, in general, steel is a very favorable material in terms of price and quality, and it is from it that the cases in most modern thermoses are made.
Temperature after 6 hours
The main property of a thermos is to maintain the temperature of the liquid poured into it. Accordingly, the key parameter of efficiency is not so much the case material or some of its heat-insulating marketing chips, but the value of the water temperature after a certain period of time. So manufacturers, confident in the quality of their products, are happy to share their achievements. The temperature value after 6 hours shows how many degrees the boiling water poured into the thermos (98 °C) will cool down at an ambient temperature of about 20 °. And values of more than 80 ° can be considered very worthy.
Temperature after 24 hours
The main property of a thermos is to maintain the temperature of the liquid poured into it. Accordingly, the key parameter of efficiency is not so much the case material or some of its heat-insulating marketing chips, but the value of the water temperature after a certain period of time. So manufacturers, confident in the quality of their products, are happy to share their achievements. The temperature value after 24 hours shows how many degrees the boiling water poured into the thermos will cool (98 °C) at an ambient temperature of about 20 °. And with values of more than 50 °, a thermos can be considered one that
keeps the temperature for a long time.
Carrying handle
The special
handle for convenience of carrying of a thermos. The design of such a handle can be different: for example, in ordinary thermoses and thermo mugs (see "Type") it is usually installed on the side, in food thermoses and jugs — from above (and is made collapsible). The handle can be a structural element of both the thermos itself and its cover (see below). In addition, the small carrying strap that some models are equipped with is also considered a handle in this case (but the shoulder strap does not count, see below).
Anyway, holding a thermos by the handle is usually more convenient and safer than by the smooth body, especially when it comes to a large-capacity model.
