The Scientist Behind Your Insulated Water Bottle

Portrait of James Dewar Inventor of Vacuum FlaskWhen you look at your water bottle, it might seem like a pretty benign object. But no matter what type of bottle you have, a huge amount of scientific ingenuity and engineering effort has been put into it. Stainless steel and plastic bottles are only possible thanks to incredible feats of engineering and industrialization that has allowed for them to become so common place, and even the humble glass bottle – by far the oldest material common to modern water bottles – has taken advantage of tons of super-high-tech developments in its production and even in the material itself with modern developments like durable borosilicate glass.

If we turn our focus onto the vacuum insulated bottle, it becomes almost impossible to ignore the importance of science in crafting water bottles. This is because, originally, the technology which makes the vacuum insulated water bottle possible was invented to be used as a piece of laboratory equipment by a man named James Dewar.

James Dewar’s Vacuum Flask and the Modern Double-Wall Insulated Bottle

Painting of James Dewar at the Royal Institution

Original Dewar Vacuum Flask at the Royal InstitutionToday James Dewar is certainly not a household name, but in his day he made his mark upon science. Born in Scotland in 1842, Dewar distinguished himself with a variety of accomplishments for which he was knighted in 1904 and nominated multiple times for (but never won) the Nobel Prize. While he made many contributions to the fields of physics and chemistry, undeniably his most enduring work has become the vacuum flask.

One of his main interests was cryogenics, the study of extremely cold materials. In particular, Dewar’s work centered on the liquefaction of gases through extreme cooling. Faced with the challenge of creating a more efficient process for storing liquefied gases, Dewar set about creating the vacuum flask as a method to keep his liquid gases from heating up for extended periods. As far back as 1872 Dewar had experimented with a vacuum insulated goblet, but the goal then was to create an insulator to keep things warm.

Building on his design from 1872 with a few changes, in 1892 Dewar put his vacuum flask on exhibit at the Royal Institution. The flask was in many ways a very simple design. As described by the Royal Institution:

“This vessel consists of glass flasks fitted one inside the other and sealed at the neck with a partial vacuum between them. The central flask is therefore insulated, keeping the contents cold and slowing down evaporation.”

In many ways Dewar had done very little to create his most enduring invention. He had more or less placed a couple of bottles inside one another, creating a limited vacuum which restricted heat transfer from the flask’s contents and the atmosphere (later he added a silver coating to further minimize heat loss.) The design was simple, but highly effective, and with the help of his vacuum flask Dewar would become the first person to create liquid hydrogen in 1898.

Patent Woes

1907 Thermos Advertisement Antique
1907 Ad for Thermos Flasks (Original Available on Amazon)

Perhaps because the flask was simply one tool of many Dewar put to work in his pursuit of science, perhaps because he never seen its commercial potential, or perhaps because it seemed like a simple thing to him, Dewar never patented his vacuum flask. It quickly gained popularity as a laboratory instrument – being put to work for its intended purpose – where it remains a ubiquitous piece of equipment to this day. Though the device was named the Dewar Flask in his honor, that was about the limit of the public appreciation he received for his invention.

Meanwhile in Germany, two glassblowers recognized the commercial potential of Dewar’s vacuum flask and set to work to create their own version they could take to market. Once they had a product, they held a naming competition to figure out what their vacuum flask should be called. A clever Munich resident submitted the name which would go down in history: Thermos. Derived from the Greek therme, which translates to “hot,” the name would go on to become not just the title for this particular brand of bottle, but eventually take on something of a life of its own as a generic term. “Thermos” was officially declared a genercized trademark in the U.S. in 1963, recognized as a term colloquially used to refer to insulated beverage containers.

Thermos went a step further from simply making their own vacuum flasks: they also secured the patent for Dewar’s invention. Despite the fact that his vacuum flask, produced and sold under the name Thermos, went on to have a massively successful and profitable commercial life, Dewar never profited from the invention, or even received any recognition outside of the laboratory for his contribution to vacuum insulated technologies.

From Cold to Hot and Back Again

Hydro Flask with Flex Cap in Cobalt BlueInterestingly enough, despite the fact that Dewar pioneered the vacuum flask trying to keep things cold, Thermos rose to commercial success on the principle of keeping things warm. While vacuum insulated bottles prove great insulators for hot or cold items, the Thermos came to be associated largely with keeping things warm. Be it your coffee or your coco, your soup or your curry, a Thermos can provide a hot meal or a warm beverage even hours after it’s left the stove.

Today Thermos is far from the only player in the world of vacuum insulated bottles. Over the course of its long history Thermos has seen many competitors and copy-cats come and go, but none have captured the public’s attention in the way the modern vacuum insulated bottle has. Relying on more or less the same principles that kept Dewar’s gases cold and liquid, companies like Hydro Flask and Klean Kanteen have put a modern spin on this century-old technology. Where a Thermos was a luxury, a water bottle is a necessity, and this new awareness to the many benefits of owning and using a vacuum insulated bottle has given a new life to this old invention.

Where the Thermos took on a focus for keeping things warm, modern water bottles tend to have more of a focus on keeping your beverages cold (at least in their advertising.) A Hydro Flask advertises its ability to keep its contents cold for 24 hours or hot for up to 12, and while it is brilliantly effective at insulating on either end of the temperature spectrum, I see far more people loading ice into their Hydro Flasks than hot soup. But regardless, the option is available, presenting another reason why these massively useful devices have made their way into our everyday lives.

Find the Right Water Bottle For You


If you haven’t already experienced how awesome having your own insulated water bottle is, it is definitely time to join the party! Be sure to read our article on the Best Insulated Water Bottles to get a look at some of the different options available on the market and our top selections.

Maybe you aren’t strictly looking for an insulated bottle – or just want to see what other options are available? Have a look at our Best Water Bottles 2016 to see what else is available before making your choice.

Still not sure you need a water bottle at all? Give our Top Ten Reasons Everyone Should Own a Reusable Water Bottle a read and see how you feel afterwards!

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Learn the origins of vacuum insulated water bottles in this brief history of the vacuum flask, its inventor James Dewar, and a tale of missed opportunity.

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