How much does a thermos hold?

If you are a lover of nature trips, hunting, fishing, then you just need a thermos. But which thermos will keep heat better? Does heat saving depend on the material of the product? Which is better to choose. Which is most effective for keeping hot tea, coffee, food?

Heat saving

Many consumers find glass flasks to leave food and drinks hot longer than anyone else. But the expert opinion is somewhat different: classic thermoses made of metal are no worse than products with a glass bulb.

The average duration of keeping food and drinks warm is 6 hours. But if the vessel does not open for a long time, different models can retain heat from 12 hours to a day.

What determines the time of heat conservation

The main purpose of acquiring a thermos is to keep food or drink hot.

You can consider several criteria that affect heat saving.

The volume of the vessel. The longer you need to keep warm, the greater should be the volume of dishes. He will leave drinks and food hot longer. If the main purpose is to store food, then, on the contrary, the size of the container should correspond to the portion. Otherwise, the air masses filling the free space will quickly cool the food.

  • Filling the vessel. This factor also affects the conservation of heat. The more the vessel is filled, the more efficiently it retains heat. Important: liquid foods will stay hot longer than solid foods.
  • Neck. For transporting food, a neck with a diameter of 25 to 60 mm is recommended. With a narrower opening in a thermos, heat loss lasts longer.
  • Flask. Glass flasks are more hygienic, but less practical. It is better to purchase a vessel with a narrow neck.
  • Material. There is no definite answer which material is better, but if the metal weighs about the same as a plastic vessel (the metal is too thin), then you can forget about heat saving.
  • The product combines two circuits: external (body) and internal (bulb itself). Between them there is a free space in which there is a vacuum or air. Heat lasts longer if there is a vacuum between the two cavities.

Varieties of thermos for thermal preservation

Thermoses can be divided into several types according to thermal preservation:


  • Classical (a thermos with a narrowed neck, it keeps heat very well, is convenient under traveling conditions). Standard volume: 500 ml.
  • Jug (vessel with a handle and nose, volume about a liter, not intended for traveling conditions, used at home). The jug is less convenient to operate and has a bulky design.
  • Thermo mug. The design of the mug is similar to a classic thermos, but is equipped with double walls, which reduces heat transfer. There is a cover. It holds less heat than a classic thermos. Volume about 500 ml.
  • Flask. Has a narrowed neck, designed for warm or cold liquids.
    Food thermos. It is used to store warm food, the neck of the expanded. Volume starts from liter. It keeps the temperature poorly, but is able to retain heat for several hours.

By volume:

  • Up to 0, 5l.
  • From 0, 5-1 liters.
  • From 1-1, 5l.
  • Over 1, 5l.

Thermos opening

  • Screw loosening. The mount is tight and tight, but wears out quickly.
  • Valve. There is a valve in the neck to extract the contents. It keeps heat better.
  • Bung. Looks like a cork bottle. It holds heat well, but is impractical in everyday life and wears out quickly.

Several factors affect heat saving: vessel volume, body and bulb material, neck width, and fastening.

According to expert opinion, the classic thermoses made of metal or with a glass bulb will best support the temperature regime at the proper level. There should be a vacuum between the walls, and the volume of the vessel should be more than a liter. Such a thermos can be used not only at home, but also in camping conditions.

Watch the video: How and Why to Prime a Thermos (November 2019).


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