Coffee thermos are a version of the vacuum flask designed to keep coffee or other drinks warm over a period of time. They work by placing two flasks, one inside the other, with a vacuum between the two to keep the temperature constant.
The vacuum flask was invented by a Scottish scientist called Sir James Dewar in 1892 and the design was later sold to the Thermos Company, who used it to mass produce the flasks. As time passed, the basic item was expanded on using different sizes and shapes and became known for carrying hot liquids such as coffee. It also became an important part of camping equipment.
Traditional FlaskThermos Stainless King 40-Ounce Beverage Bottle, Midnight Blue
This is the modern version of the classic vacuum flask made with TherMax double wall vacuum designed to keep liquids hot for 24 hours or cold for the same period. It is made from stainless steel so the exterior bottle remains cool to the touch regardless of the contents and it is also sweat proof. The lid doubles as an insulated serving cup with a twist and pour function that allows access to the liquid without taking the stopper out completely. It has a 40-ounce capacity and comes in a choice of two colour finishes.
Backpack thermosThermos 16-Ounce Stainless-Steel Backpack Bottle, Silver
For a smaller version that is ideal to fit into a backpack, this product has a 16-ounce capacity and can still keep liquids hot for 8 hours and cold for 12 hours. It has the same cool touch exterior and the vacuum technology inside as well as having a leak proof lid. There is also a hygienic cover in the lid and easy push button to seal it with a locking ring. This light and easy to carry thermos will fit into most cup holders in cars too.
Cleaning and care
The best coffee thermos will have a long life, especially if cleaned and cared for properly. There are a few tips to using the thermos to get the best out of it and see it lasting the longest:
- Clean with warm water and washing up liquid before the first use
- Before filling with hot or cold, fill with hot water or cold water for around three minutes
- If not used for a while, rinse with warm water before using
- Don’t overfill the flask – remember to leave enough room for the stopper without pushing liquid out
For generally, day to day cleaning, use warm water and washing up liquid, rinse thoroughly with hot water but don’t leave it immersed in water. Make sure you dry it out before storing and leave it stored without the stopper in place. Don’t clean it in the dishwasher.
Over time, stains can build up inside the thermos, particularly from coffee. The simplest way to remove these is to fill the flask with hot water and add a teaspoon of bicarbonate of soda. Don’t put the stopper on when doing this and leave the thermos to soak overnight. The next morning just give it a thorough cleaning out before using again. Avoid abrasive products, bleaches or solvents.
Never leave a carbonated drink or dry ice in the thermos with the stopper on as this can cause the stopper to be ejected forcefully – a little bit like a party popper! It is also advised not to use thermos to keep baby milk or baby food in as there is a risk of bacterial growth inside.
As well as producing coffee thermos products, the same Thermos brand produce a range of products for other uses. One of which is their Food Jar range that is ideal to carry hot food such as soups or other liquid-based foods. It works in the same way as the coffee thermos with the vacuum layer keeping the content of the inner flask warm while the outer one remains cool to the touch.
Thermos also produce a range of sippy cups and toddler cups using the same technology but adapted for use by little people. These also come in a range of attractive colours and fun characters that will entice the kids to make use of them.