The Ins, Outs, Vacuum Seals, and Double Walls of the Many-Splendored Thing Called “Thermos”

Looking for a custom coffee thermos or other thermos promotional product? You’ve come to the right place. But before we show you best bets, let’s unpack why the promotional thermos is such a great drinkware gift.

What Is a Thermos?

Thermos is the most popular brand name of what’s technically a vacuum flask or insulated food and beverage container. So popular, in fact, that Thermos lost its trademark in 1963 when it became clear that “insulated food and beverage container” would never be used instead of “Thermos” to describe double-walled, vacuum-insulated wonders. Much like now-generic terms such as ChapStick, Kleenex, Popsicles, and Post-it Notes, the term “thermos” is widely used for a plethora of vessels designed to keep food and drink at temperature. 

How Does a Thermos Work?

It’s all about heat transfer. If heat can’t leave a hot beverage, or come in contact with a cold one, the drink inside will stay at temperature longer. And since one of the ways heat travels is through the air, no air means less heat transfer. And the best way to prevent heat transfer is through vacuum insulation (or lack of air) between the hot (or cold) beverage and the world outside. Vacuum insulation between beverage and air is created through a thermos design that features an external and internal wall (double walls) that are sealed at the top after all the air has been sucked out. 

If It’s Double-Walled, Is It a Thermos?

Not necessarily. In order to count as a thermos, the vessel needs to be both double-walled plus vacuum-insulated. A double-walled tumbler without the vacuum insulation will keep condensation from forming on your hand or on your desk, and will keep your beverage at temperature longer than a single-wall option, but not as long as the double-wall, vacuum-insulated thermos. Also, because vacuum insulation is inefficient unless you’re working with stainless steel, a genuine thermos style vessel will have stainless steel interior and exterior walls.

Can Anything Top a Vacuum-Insulated, Double-Wall Promotional Thermos?

Well, actually, yes. And that’s a copper-lined, vacuum-insulated, double-wall promotional thermos. The copper lining helps distribute the hot or cold of your beverage more evenly throughout the vessel, helping to maintain temperature longer. Also, the copper lining serves to reflect back heat that would escape from a hot beverage or heat that would come into a cold beverage. If you’re customizing a thermos and want to go top notch, check out the Thor Copper Vacuum Gift Set.

Show Me Some Thermos Promotional Products I’ll Love

Sure thing. Whether it’s a throw-back style or a discreet streamlined option, there’s a thermos to suit any brand and any recipient. Our favorites: 

• For a thermos that’s durable enough for a construction site, wilderness trek, or fishing trip, customize this Vacuum Thermos – 33 oz.
• For work, school, day hikes, and picnics in the park, they’ll sip in style with this sleek Stainless Steel Thermos – 16 oz.
• When handsome, rugged, and high function are the name of your giveaway game, go for the Swiss Force® Alpine Double Walled Vacuum Bottle.
• Could be coffee, tea, or chilled chardonnay inside the elegant Companion Thermos – 16 oz. This custom coffee thermos is just the right size for convenient sipping anywhere, anytime.

A thermos is designed for durability, making it a great choice for a personalized gift. Given as a customer appreciation gift (Customer Appreciation Day is May 21st), an employee gift (Employee Appreciation Day is celebrated the first Friday in March), party favor, or souvenir, a promotional thermos promises to keep your name in circulation longer.

P.S. For more customized drinkware ideas, check out our blog, The Ubiquitous Custom Coffee Travel Mug.