pouring flask 2While we easily say “thermos flask” when referring to the household item we use to keep things hot or cold, the name “Thermos” is the trademark of the company formed by the two German glassblowers, who first patented and manufactured these flasks in 1903.

To name their flask, the worthy gentlemen held a contest, and a resident of Munich submitted the name “Thermos” , derived from the Greek word “Therme” meaning “heat”.  In 1904 “Thermos GmbH” was registered and started producing glass liner insulated vacuum flasks for hardworking German factory workers.  There was such demand for the product that by 1907 the parent company sold the trademark rights to three independent companies, The American Thermos Bottle Company of Brooklyn, NY, Thermos Limited of Tottenham, England, and the Canadian Thermos Bottle Co. Ltd. of Montreal, Canada.

As had been the case in Europe, “Thermos Flasks” proved very popular and were soon in high demand.

By the First World War, the product and the company had became synonymous, helped on by it’s popularity and a clever marketing strategy and soon all vacuum flasks were called “thermos flasks” regardless of the manufacturer. This has persisted despite the fact that the Stanley Insulating Company has produced steel vacuum bottles since 1913 and the Zojirushi company has produced vacuum flasks in Japan since 1948.

The American Thermos company led the way and by the 1920’s were buying out other thermal product companies. Not that this place of  honor was not earned, considering that Thermos America continued to lead the industry with innovations in vacuum flask technology and improvements in the materials used to create flasks. For instance they were an early adopter of Pyrex glass and by 1928 had engineered a new type of vacuum insulated, double walled Pyrex liner. It proved very popular for use in cooler cabinets just prior to the invention of commercial refrigeration.


Vintage Stanley Flask 1913
Vintage Stanley Flask 1913


During the Second World War most of Thermos America’s production was geared to the war effort and it is said that every time a bombing raid went out over Europe, 20 000 to 30 000 thermos flasks went along.

After the Second World War, Thermos continued to explore new markets and diversified it’s product lines to include  similar or complimentary products including BBQ makers and insulated chests. To reflect this, in 1956 the name of the American operation was changed to “The American Thermos Products Company” and the Canadian to “Canadian Thermos Products Limited”. In 1960 both companies were acquired by the King-Seeley and in 1968 the King-Seeley Thermos Company was itself acquired by Household International.

As the flagship of Household International though the 1980s, Thermos became synonymous with BBQ grills, insulated chests, glass-lined thermos products, camping gear, lunch boxes and coffee carafe’s as well as other products.

In 1989,  Household International sold off many of its manufacturing operations and Thermos in the US, UK, Canada, and Australia were sold to Nippon Sanso. From this sale the Thermos Nissan brand was born.

In 1997,  restructuring of the Thermos Nissan companies saw the Thermos Company (the name it had acquired during a previous restructuring in 1986) shrug off all it’s various product lines to come back  to the product that they started with: insulated food and beverage containers.

While the “Thermos” brand remains a registered trademark in some countries, and despite several attempts by the company to protect the trademark, it was declared a generic trademark in the U.S. in 1962, as a result of it being the household name for such a container.

In case you are like me and want it all laid down proper like, the correct name for the flask would be a vacuum insulated flask . If on the other hand you work in a laboratory, you may prefer the scientific name Dewar flask or Dewar bottle after Sir James Dewar, who perfected the principles of vacuum insulation so that he could keep chemicals cold in 1892 (see How Does A Thermos Work?).


Technology improvements as well as consumer demand has seen the flask evolve too. The coffee flask which was primarily used for keeping liquids hot or cold, has changed into a whole range of  products of different size and shapes which are often specialized for uses such as insulated water bottles, food jars and travel mugs.

61 ounce Thermos Nissan
61-Oz Thermos Nissan Flask


See also: Chronology of the Thermos