How to Choose a Thermos

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.

Selection Tips

• • 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.

Usage Tips

• • 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.

Kind

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.

Purpose

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.

Volume

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).

Material

Frame

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.

Flask

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.

Lid

Clos­ing method

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.

Usage

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

Clos­ing method

Cork hap­pens screw and plug-in. With good tight­ness, the plug is incon­ve­nient to use and short-lived. There­fore, this solu­tion is rare.

Plug type

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.

Safety

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.

Design

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.

Equipment

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.