Type
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Thermos. Thermoses of a classic design: rather narrow and tall cylindrical vessels with a small diameter of the neck. They are intended mainly for a relatively pure liquid without impurities or with a minimum of impurities — tea, coffee, etc. Such vessels can be hermetically sealed, making them convenient for long hikes and trips. The average capacity of a classic thermos is from 500 to 1000 mL, but in general the range of such models is quite diverse.
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Thermos jug. A type of thermos designed mainly for home use and not intended for travel use. Distinctive features of such models are, firstly, rather large volumes (usually from a liter or more), and secondly, a spout for easy pouring of contents. Also note that it is among the jugs that the pump for liquid is most often found (see "Opening / serving"), in other types of thermoses such a device is practically not used. A thermos jug can be useful, for example, for storing a supply of hot water for tea parties during the day.
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Mug-thermos. Mugs with reinforced thermal insulation that allows you to keep the temperature of the drink for a long time. However, such vessels are designed primarily for ease of use “on the go”, and not for long-term storage of the contents (this is how thermo mugs differ from the thermos flasks described below). The design of thermo mugs often provides for valves or drinker
...lids (see "Opening / serving") that allow you to drink without opening the lid. Models with twist-on lids are somewhat less common — they retain heat more reliably when closed, but lose it faster when drinking. The capacity of all thermos mugs, of course, is small — usually up to half a liter.
— Thermos flask. Relatively small thermoses, shaped like "sports" bottles or camping flasks for water. The key difference between such models and conventional thermoses is that the contents of the flask can be drunk directly from the vessel without pouring it into a separate container (whereas it is difficult with a classic thermos, it is better to use a cup with it). At the same time, flasks are better suited for long-term storage of drinks than thermos mugs (see above), they can be used not only for drinking on the go, but also for transporting drinks on a long journey.
— Food thermos. Thermoses designed for hot food — soups, cereals, etc. A distinctive feature of such vessels is a wide neck through which not only liquid, but also rather large pieces of solid food can freely pass. In addition, the large neck width makes it easy to clean after use. And some models even come with containers for added convenience (see below). The volume of a food thermos can be up to several liters, although there are options for 400 – 500 mL.
— Children's thermos. Thermoses intended for children differ from "adult" models mainly in their reduced size and characteristic bright design. In terms of functionality, most of these models correspond to classic thermoses, however, there are other options — in particular, thermoses-flasks and food containers (for more details, see above).
— Automug. Specialized thermos mugs designed for use in a car. The key difference between such dishes and ordinary thermos mugs (see above) is the presence of a heating system powered by a car cigarette lighter. Auto mugs can be very useful on long journeys on roads where there are rarely cafes, gas stations and other places where you can get tea or coffee.Brew strainer
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The brew strainer allows you to prepare tea directly in a thermos. To do this, you just need to pour the tea leaves into the strainer and fill the thermos with boiling water. The tea strainer is a fine mesh, most often metal, that holds the tea leaves, preventing it from falling into the spill. Thanks to him, the purity and hygiene of the thermos, as well as the tea itself, increases. There are various options for the brew strainer. Often the sieve is simply built into the neck. In this case, the strainer acts as a coarse filter. Many thermoses have a strainer in the form of an elongated cylinder, with a deep immersion in boiling water. There are also other designs of the custard strainer.
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French press. A thermos with a French press allows you to brew natural ground coffee directly in a thermos. The French press itself is represented by a disc filter, which is pressed against the handle. When pressing on the handle, the disc filter presses the tea leaves to the bottom, thereby filtering out large coffee ground particles. The basis of the disc filter is a metal mesh. Under the grid it is recommended to put a special filter paper. Disposable paper filters are inexpensive. A French press performs two functions at once: pressing and filtering. The French press removes the bitterness of phenolic resin from coffee, which makes the coffee softer and more pleasant than ever.
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.
Opening/supply
The type of main cover provided in a thermos. The main cover in this case is a device that directly covers the working volume of the vessel; an additional cap can be installed on top of it, which often also plays the role of a cup. In modern thermoses there are the following types of main lids:
screw-on (screw),
valve,
cover,
hinged cover,
drinking cover,
pump (pump),
stopper. Here are the features of each of them.
- Screws on (screw). Solid (without holes) screw-on cover, secured with a thread. Such lids are very simple and at the same time reliable, but you cannot drink or drain the contents through the classic screw - you have to remove it completely. There is also a more advanced design that allows you to drain the contents without removing the screw - just partially unscrew it; however, this is a rather specific option that is not used often. Be that as it may, twists are found mainly among classic and food thermoses (see “Type”), for which the mentioned nuances are not decisive.
- Valve. A cover (most often threaded) equipped with a valve through which the liquid contents of the thermos can freely flow. Such lids are more complex and more expensive than “blind” screws (see above), but to access the contents you d
...on’t need to unscrew the screw every time, just open the valve. This not only provides additional convenience, but also reduces heat loss. Thanks to these advantages, valves are extremely popular in classic thermos flasks; they are also often used in thermal mugs (see “Type”). The disadvantages of this option include the fact that the valve opening is usually made quite narrow and is easily clogged with impurities (for example, tea leaves or coffee grounds). Therefore, the valve can only be used for liquids without such impurities (this also applies to food thermoses, which can also be equipped with valves). However, there are models with two different valves included, for drinks of different consistencies and aromas.
- Lid. Lids in this case are devices that do not have threads (unlike the screws described above) and are held in place solely by friction or a latch. The design of the lids can be different: some cover the neck from the outside, others are pressed inward when closing; There are also more specific options. In any case, the lids are easy to remove and put back on, but they are not very reliable - for example, it is not recommended to turn such vessels over. Therefore, this option is found mainly in thermal mugs and thermoses for food (see “Type”), for which the mentioned disadvantages are not critical.
— Hinged cover. A variation of the lids described above, which, when opened, is not removed entirely, but is folded to the side on a special mount. Thanks to this, the likelihood of loss is reduced: in fact, you can only lose the cover along with the thermos itself; and a latch, spring, or other similar device is usually provided to hold the cover in the open position. On the other hand, mount somewhat affects the price and dimensions of the vessel. This drawback is least critical for flasks and mugs (see “Type”), and it is among these types that hinged lids are most often found.
— Cover-drinker. Lid (regular or threaded), complemented by a special hole for drinking. This design allows you to drink from the vessel without removing the cover; and during “non-working” hours the hole is covered with a flap or other similar device. Drinking lids are extremely popular in thermal mugs and auto mugs (see “Type”): they allow you to drink from the mug comfortably while at the same time minimizing heat loss and the likelihood of spilling the contents.
— Pump (pump). Lid (classic or threaded) with built-in pump. Most often, this pump is activated by a special button: when you press this button, a portion of liquid comes out of the spout, and the thermos does not need to be tilted. However, such devices are quite complex and cumbersome, so it makes sense to use them only in thermos jugs (see “Type”): the size and weight of the pump is small compared to the dimensions of the jug itself, and tilting such a thermos can be difficult - it’s easier to use a pump.
- Cork. A classic stopper that fits tightly into the neck of a thermos and is held in it without threads or other similar devices. Corks differ from the lids described above in their greater thickness, and also in that they are inserted into the neck from the inside (while the cover can cover the vessel from the outside). Plugs are very easy to use, but have low reliability, which decreases even more as they wear out. As a result, this option has practically fallen out of use.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.
Temperature indicator
The temperature indicator shows the degree of cooling or heating of the contents of the thermos in real time. It can be represented by a display, thermometer or other sensor to visually display temperature. Thus, there are thermoses in which the temperature indicator is a chameleon coating that changes color depending on the temperature. Thermoses with an indicator are especially convenient for long trips, hikes and travel. Temperature control allows you to correctly plan the time of eating/drinking and organize timely replacement of the contents of the thermos.
