I would like to do a review on the humble Vacuum flask, sometimes referred to as the Thermos, after the specially Company which was formed to sell it. The Vacuum flask was actually invented by a Scotsman, Sir James Dewar way back on 1892!
The basic principle is simple, any liquid in any container will try to get to the temperature of the air outside it, it does this by conducting the heat, . In the case of a Vacuum flask, the inner walls have a cavity, which is devoid of air, and is as near as dammit a perfect Vacuum. Obviously heat can not be conducted through a Vacuum, so the liquid will remain at the same temp for a long time. The only drawback being the top or stopper, this will conduct heat, so it helps to keep the flask upright.
The construction of modern Vacuum flasks, is either Stainless Steel, or traditionally Plastic. few Years ago they were made from Steel, and always started to rust. These were usually recognised by their Tartan pattern, and the fact that they would break their liners at the slightest knock. I do have a Stainless Steel one, which is brilliant. It has been dropped countless times, and never breaks.
I also have a Massive Three Litre one! This has a wide neck, and is made for Liquid Food, such as Soups & Broth.
You will usually find that there is a cup or two fitted to the top of the flask, so more than one person can have a drink at the same time.
I have placed this review under Camping Equipment, which is where it belongs, although there re quite a few more categories which could accept it.
I use one when Truck driving, and have also found them useful while Fishing, working on Building Sites, Walking in the countryside, and many more pursuits.
When dispensing drinks from a Thermos, be careful if the liquid is hot, it can still scald you. Also make sure the top goes back on straight away, or your next drink will be less than hot.
A lot of people forget that these can be just as useful for keeping drinks cold, you can be out walking in the Hills, for hours on end, in brilliant Sun, and a cold refreshing drink is always available, in your backpack!
I can thoroughly recommend these Vacuum flasks, especially the ones made by the famous Thermos Company. Every home should have one.