Taste The Earth Blog

What's The Difference Between Thermos And Tumbler?

by Mark Morphew on Apr 17, 2022

What's The Difference Between Thermos And Tumbler?

Tomato Tomahto. The difference between a Thermos and a tumbler is so insignificant for most people they're practically the same thing. But when you pause, step back, and take a closer look, a few characteristics actually differentiate them from one another.

For starters, one is better suited for throwing in your backpack when you hit the road. The other is the perfect travel buddy that sits in your car's cup holder and keeps you caffeinated in the morning rush hour traffic.

Want to know more? Keep on reading if you're confused about both types of insulated drinkware and still have some niggling unanswered questions. In this article, I have all the answers.

Thermos Is A Vacuum Flask

Wait, what!

Before we dive in, did you know that Thermos is actually the brand name for a regular insulated vacuum flask?

The brand has become so popular the term is used for almost any type of insulated flask or tumbler, even if it's not a Thermos brand.

So, the question should really be, what's the difference between an "insulated flask and a tumbler." Essentially that's what we are comparing.

Let's take a closer look.

Thermos vs. Tumbler

So what's the difference between Thermos, cough, I mean insulated flask, and a tumbler?

To better understand both types of drinkware, below I have pulled back the veil and taken a fine-tooth comb over each. Here's what I found.

What Is A Thermos?

Okay, by now, when I say Thermos, you know I actually mean an insulated flask, right?

Anyway, a Thermos is essentially a cylindrical stainless steel bottle with a screwcap and a cover that doubles as a drinking cup. Some also feature a flat, in-line handle for easy carrying.

They are perfect for throwing in your backpack when you go on a hike or camping trip. The beverage won't leak because of a tight-fitting screwcap, even when the flask is laid on its side.

There's a vacuum layer between the inner and outer walls for insulation. This unique design stops heat transfer and keeps liquids either hot or cold for extended periods.

It does such an excellent job with temperature retention you can keep coffee hot for up to 7 hours or longer. Pretty impressive.

What is a Tumbler?

On closer inspection, the tumbler functions in a similar way. The best tumblers also feature vacuum insulation, so they too can keep hot or cold drinks at an optimum temperature for hours on end.

But the key difference between a Thermos and a tumbler is how they look and both are used.

For the lack of a better term, a tumbler is more like an insulated mug and is better suited for hot drinks or cold beverages you want to enjoy on the go.

They come with a plastic lid and a mouthpiece so you can slurp on your favorite beverage with ease. There's no screw cap to mess around with - just slurp and go!

Most of the best tumblers have a slight contour at the bottom to fit inside a standard car cup holder. Some even come with handles, like a regular coffee mug, but for the most part, handles are not a prominent feature.

However, unlike the Thermos, the lids aren't really that effective when it comes to accidental leaks.

Sure, you can happily sip away on your iced latte while navigating the morning traffic, but they won't do too well if you decide to go bungee jumping with one in your back pocket. If you know what I mean.

What's Better Than A Tumbler?

A ceramic coated travel mug, that's what!

A travel mug is essentially a tumbler: same thing, different name. Tomato Tomahto, okay, you get the point.

Here's the lowdown on the advantages of a tumbler with a ceramic coating. You get all the benefits of a tumbler without sacrificing taste.

Hear me out.

The ceramic coating keeps nasty metallic and plastic tastes from leaching into your favorite beverage. Pretty neat.

Have you ever drunk from a metal cup and couldn't quite put your finger on the strange taste?

It's your drink reacting with the metal cup. You don't drink out of a metal cup at home, so why should you when you're on the go.

Like what you hear?

Well, you've landed at the right place.

We have a range of premium ceramic-coated travel mugs that we think you'll love.

👉 Head on over here to check out our best seller.

The Bottom Line

Okay, are you still with me?

To summarize. The tumbler is a large cup with a plastic lid and mouthpiece for easy slurping. The Thermos almost always has a tight-fitting screw cap and a plastic cover that doubles as a cup.

Thermos is excellent for keeping drinks safely locked inside, and there is almost zero chance for any leaks. A tumbler, not so much.

But both can keep drinks hot or cold for hours. The Thermos does have a slight edge and holds the temperature for slightly longer due to the screw cap, which aids in additional insulation.

That's really all there is to it. If you want to go hiking, best reach for the Thermos. Want to enjoy a drink while commuting? The tumbler is your friend.


Mark MorphewMark Morphew is a freelance writer specializing in digital marketing and the hospitality sector. He helps coffee, catering, and food tech businesses create better content that drives more traffic and increases customer engagement.