A thermos - a cylindrical vessel for storing food while maintaining their initial temperature. It consists of a body and a flask with two walls, between which there is a vacuum space acting as a heat insulator. Also comes with lid and stopper. Thermos is indispensable for long trips and short walks, for picnics, fishing and hunting.
- When choosing a thermos, make sure that there are no defects outside and inside the product. It should not have cracks, chips, dents, scratches. If the design includes buttons and levers, evaluate their reliability.
- Carefully inspect the lid and cork, check the tightness of the connection of these parts with the body, as well as the integrity of the silicone seal of the cork. The thermal insulation properties of the thermos largely depend on this (up to 40% of heat is lost due to the cork). The simpler the design of the thermos, the better the initial temperature is maintained.
- Refuse to buy a thermos with a flask that emits a sharp unpleasant odor — such a product can be harmful to health.
- It is recommended to shake the thermos: knocking or rattling indicates an unreliable fastening of the flask. Such a model will quickly fail (the glass bulb will break).
- At home, pour boiling water into the vessel and leave for 10–30 minutes. If the case is hot, then the thermos has problems with tightness and thermal insulation. This product is considered defective.
- Avoid hitting or dropping the thermos. Practice shows that even minor damage to the housing can result in a loss of vacuum.
- Before using the thermos, rinse it with water.
- Store and carry the thermos only in an upright position so as not to spill the contents.
- A partially filled vessel retains heat worse than a full one.
- Do not store carbonated drinks, hot oil, brine, dry ice, baby food, dairy products in the container.
- Do not store drinks in the container for more than two days. It is also not advisable to leave food that can turn sour.
- It is not recommended to close an empty thermos tightly, otherwise an unpleasant odor will appear. But even in a fully filled vessel, it is recommended to leave a small gap under the cork. This will protect against burns when opening the lid.
- Do not wash the thermos with alkaline solutions.
Standard thermos — a vessel with a narrow neck, designed to store liquid products. At the same time, the presence of a minimum of impurities in the liquid (tea, coffee) is allowed. A classic option for leisure and travel.
Children’s thermos — a smaller version of the usual “adult” thermos. Features a striking design.
Thermos for food (food) — characterized by a large volume and a wide neck. It is cylindrical and rectangular. Liquid and solid food is stored in such a thermos. Some thermoses are equipped with a removable container, bowl, spoon, fork.
Important: food thermos retains heat worse than other varieties. Unlike most models, these thermoses have a foam or foam padding instead of vacuum insulation.
Thermos jug – equipped with a spout and a handle that facilitate pouring liquid. Suitable for home use, such as hot tea storage. The bulkiness and fragility of the vessel does not allow the use of such a thermos in travel and hiking.
Pump thermos — has a very large volume. Equipped with a pump and a lever that provides access to the product without turning the thermos over and opening the lid. This is a stationary model for offices, cafes, fairs and street parties.
Thermoflask — has an oval or flat shape, resembling a flask. Individual copies imitate the appearance of army flasks and are complemented by appropriate accessories — fastening for unloading or belt, protective color covers. It is used to store cold drinks, as it is easy to burn yourself with hot liquids due to the narrow neck.
Thermal bottle / thermo mug – has a small volume, it is convenient to drink directly from the container. Such a thermos refers to individual dishes and is not designed for long-term preservation of temperature. A thermal mug is convenient to use at work or fishing.
Car club – thermo mug for drivers. Equipped with a heating function (from the cigarette lighter, 12 V). It will come in handy on long trips on roads where it is difficult to find coffee or tea.
portable - light and compact thermos, usually designed for one person.
Tourist – characterized by increased strength and resistance to environmental influences. This model is the most common.
Domestic - Differs in large volume and dimensions. Used to store food at home.
This characteristic means the maximum amount of liquid or solid food that a thermos can hold. Depending on the model, the volume ranges from 0.3–3 liters or more. The higher the volume, the more product you can take with you and the slower it cools down. At the same time, with an increase in this parameter, the dimensions, weight and price of a thermos increase.
By volume, thermoses are divided into the following categories:
- 0.3–1 l — thermal bottles / thermal mugs, thermal flasks;
- 1–2 l — standard thermoses, thermoses-jugs (reasonable balance between volume and dimensions, good thermal insulation);
- 2–3 liters or more — food and pump thermoses. This group also includes stationary thermal containers with a capacity of up to 40 liters, which are used only indoors.
Approximate volume of the thermos:
- 0.5–0.7 l — for a trip of one person or a walk of two people;
- 1–2 liters — for a family consisting of two or three people;
- 1.5 liters or more — for long hikes or company holidays (start from 0.5–0.7 liters per person).
Stainless steel — Differs in an attractive appearance, durability, resistance to external influences. Cons: relatively high cost, high weight, low thermal insulation. A thermos with a steel body and flask is an ideal choice for hiking.
Plastic - light and cheap, has good thermal insulation. Such thermoses differ in a variety of shapes and colors. Cons: fragility, susceptibility to scratches.
There are also models with a case made of composite materials (stainless steel + lining, stainless steel + plastic), which provide additional comfort. Rubber pads prevent the thermos from slipping in your hand, and plastic improves thermal insulation.
Stainless steel — reliable, but poorly retains heat and oxidizes over time, and this worsens the taste of drinks. Therefore, manufacturers often use more expensive stainless steel with a coating that protects the metal from oxidation.
A stainless steel flask is difficult to maintain and is not suitable for storing yoghurts and other products with high acidity (possible consequences: “steel” taste of food, damage to the coating).
Plastic — retains heat well, but is sensitive to high temperatures and absorbs the smell of liquid. This property spoils the taste of other products. A plastic flask is found in thermo mugs.
Important: Avoid thermoses, in which the flask is made of very cheap plastic. Such products are hazardous to health, as they are capable of releasing toxic substances.
Glass — unlike stainless steel, it does not oxidize, it retains heat better and is easier to clean. Minus — fragility. Great for connoisseurs of aromatic drinks, because it does not change the smell and taste of the contents. Suitable for storing food with high acidity. But on hikes, such a thermos will quickly break.
Important: do not lay thermoses with a glass flask and a regular cork horizontally. In this case, a gap may appear between them, which will lead to fluid leakage. It is better to choose a more reliable model with a stainless steel flask and a composite stopper (plastic + rubber seal).
Cork and cap
The cork and lid are made of plastic or metal (stainless steel). Composite solutions (stainless steel + plastic, stainless steel + silicone) are sometimes used as a material for the cover. It is more convenient to drink hot drinks from such a lid. It is better not to take a purely metal version in order to avoid burns to your hands and lips (if you use the lid as a cup).
Stoppers are usually equipped with a rubber or silicone seal, which improves the tightness and thermal insulation.
screw — provides good tightness, allows the storage of liquids with impurities, such as tea. Cons: wear of the lid with frequent unscrewing and tightening, large heat losses (the neck remains open). It is used in thermoflasks and food thermoses.
Hinged with valve — eliminates the need to constantly twist and unscrew the lid, which prolongs the life of the thermos. This method retains heat well. Cons: prone to clogging due to the storage of fluid with impurities, loss of tightness when clogged. The optimal solution for “clean” or pre-filtered liquids.
Snap-on lid — easy to close and open, unlike previous options. Minus — low tightness. It is used in thermocups and thermoses for food.
Depending on the diameter of the lid, it can be used as a cup lid (comparatively narrow) or as a bowl lid (wider). Most often there are thermoses with a lid-cup.
Cork happens screw and plug-in. With good tightness, the plug is inconvenient to use and short-lived. Therefore, this solution is rare.
Stopper without button — resembles a wine bottle cork, the simplest option. Minus — with frequent unscrewing / twisting, it wears out quickly, which leads to heat loss and leakage of the thermos.
Push button valve — allows you to quickly access the contents of the thermos without unscrewing the cork. Cons: less reliable, worse thermal insulation compared to the previous option. This option is good if you need to pour liquid frequently.
Valve with lever – blocks / unblocks the pouring of liquid, which is convenient. Cons: poor tightness, complex design, reducing reliability. Such a cork is equipped with individual models of tourist, portable and children’s thermoses.
Drinker valve — makes it possible to drink liquid directly from a thermos. Common in children’s models, thermo mugs and thermo flasks.
Temperature retention time
This parameter indicates the time during which the initial temperature of the product is maintained (with small deviations). Depends on the volume of the thermos, the width of the neck, the materials of the flask and body.
The temperature retention time usually does not exceed 6–8 hours. Some models are able to maintain heat or cold for 12–24 hours. But food thermoses retain heat for only 1–3 hours.
Important: To keep hot food warm longer, add hot liquids, such as gravy, if possible. A great option is puree soup. You can warm up the thermos before filling it with hot food. Ice cubes will help keep the temperature of cold food, which are stacked before loading the thermos.
Shockproof - Highly resistant to mechanical damage. Ideal for hiking in difficult conditions.
Without bisphenol A – plastic parts of the thermos are not hazardous to health. Bisphenol A is a toxic substance that adversely affects the brain, reproductive system and other organs.
Colorful design is characteristic, first of all, of children’s thermoses. Such products are decorated with drawings of animals or characters from fairy tales / cartoons. Sometimes you can find “adult” models with the image of flowers.
Dimensions and weight
The weight and dimensions of the thermos are determined by its type, the materials used. If the vessel is in the car most of the way, these parameters are of secondary importance. But for a hiking trip, you should pay attention to the size and weight of the product, since a roomy thermos takes up extra space in the backpack and increases the load on the person.
Heating – maintains the temperature of the product, and, if necessary, heats it up. This function is most often provided in thermo mugs.
Spoon / fork – is included in the package of food thermoses. Some models combine the functions of a spoon and a fork.
Cup / bowl — found in food and conventional models. It will come in handy if several people are participating in the campaign. The function of the cup is usually performed by the lid.
Container - container for food. Several containers (2–3) are used as bowls, and also make it possible to divide food into portions even when loading a thermos. Containers are placed inside the flask or connected to each other into a single vessel.
Carry handle — allows you to carry a thermos in your hand, which is convenient. At the same time, the dimensions of the dishes increase.
Shoulder strap for carrying — unlike the previous version, frees hands. It is provided in bulky food models that are easier to carry on the shoulder than in the hands.
Carbine - designed for attaching a thermos to a backpack, a tree branch or an awning stretch. Such a device is equipped with tourist models that are used on long journeys.
Case – facilitates the transport of the thermos and protects it from scratches and dirt. In addition, the cover improves the thermal insulation properties of the thermos, as a result of which the contents retain their temperature longer.