Thermos

Once upon a time, a Scottish man named James Dewar, a scientist employed at Oxford University, discovered that if he created a tightly-sealed vacuum between two nested vessels, the temperature of the product in the inner vessel would not change very much over time. The commercial applications of this were realized quickly as German glassblowers sold what came to be called Thermos jars.

I own such a device, and it is truly miraculous. This morning, The Wife and I brewed a pot of coffee. I filled my Thermos with hot coffee and sealed it up tightly. Away I went to work and several hours later, I opened up my Thermos and poured myself a hot cup of Joe, with the exact right amount of creamer and sweetener in it.

After a long day at work, and after more than twelve hours of storage, there was still a cup full of coffee in the Thermos this evening. While it was not as hot as it had been when poured fresh, it was still drinkably warm. (This is because by opening and closing the bottle during the day, I allowed air to enter into the inner chamber, and the coffee radiated some of its warmth into that air.)

The Thermos has been largely ignored by my generation. We much prefer to get Starbuck’s than brew and carry around our own coffee in a large, awkward container. It’s too bad, really. A pot of home-brew coffee costs about fifty cents, (maybe as much as sixty cents, after you add all the creamer that I like) as opposed to a grande coffee-of-the-day at Starbuck’s, which is going to set you back about two bucks (plus tip). Six times as much coffee for 25% of the price. That Thermos pays for itself after about a week.

So yes, I’m back on the caffeine. But there’s uses beyond coffee, too — I’m thinking about having hot homemade soup as part of my lunches later this week.