Sep 16, 2020

The coffee thermos designed by Zojirushi


travel mug that cannot retain heat shouldn’t be called a travel mug. While these mugs are designed to keep all beverages hot (or cold) for extended periods of time, not all of them actually do so. Only top-notch models like Zojirushi are capable due to their unique design, keeping any liquid as hot as when you first poured it in!

The reason why we're singing praises for Zojirushi’s SM-KHE48AG Stainless Steel Mug, is that we tested this small coffee thermos out for a few months to see how it holds up with everyday use. And like the Zojirushi Coffee Maker, it doesn't disappoint. Read on for our detailed assessment of its six key parameters: material, design, insulation, performance, cleaning, and cost.

If you don’t want to read the entire article, go through our “In A Nutshell” section for a quick review.

Check it out on Amazon here

Material: Dual Layered Stainless Steel Construction

Like Zojirushi coffee maker, this small coffee thermos is made primarily of 18/8 stainless steel. It's the most flexible austenitic form of stainless steel. The lid and other parts are made of BPA free plastic, which is non-toxic and hygienic.

Due to this reason, the mug is very lightweight. Weighing only 9 ounces. Which is considerably lighter than its competitors. It houses a dual-layer of stainless steel. Meaning, the heat from your hot coffee stays trapped inside the inner chamber and won’t quickly dissipate to the outer layer. At the same time, it prevents the mug from getting too hot.

Design: Thoughtful and Clever

While it looks a lot like other travel mugs in the market, it has a few noteworthy design features that make it more useful. It's tall, compact, and comfortable to hold like other travel mugs. What seems like a basic design from the outside, turns out not so basic when you consider its superior engineering.

Made in Thailand

Zojirushi has a flip-top cover that opens like magic. Apart from covering the top, it serves a few other purposes you won't get in most thermos mugs. Not only does it prevent spills and leaks, but also keeps the mouthpiece sanitary and hygienic by covering it entirely when not in use.

A unique feature of the cover is its lock. While testing, we found out that keeping the top locked down is very useful to prevent any leaks. The lock and lid can be easily operated with only one hand – another plus for on the go coffee sippers.

The lock of this model is designed in a way that prevents any errant condensation drops from dispersing when the lid is open. Therefore if you're concerned about coffee stains, you'll definitely appreciate this feature!

While testing, the only design flaw we noticed was the sheer number of parts. Apart from the mug itself, it has at least half a dozen smaller pieces. Which can sometimes be a little too much to handle. For example, the lid has a removable sipping mouthpiece, rubber stoppers, multi-piece plastic hinge, and a metal spring.

This design works reasonably well in a day to day setting. For regular office or home use, you won’t have any issues with cracking or breakage.

Insulation: Better Than Expected

We started out filling this small coffee thermos with coffee at 5:00 PM, and checking it periodically to notice how much heat is retained. With the lid tightly closed the entire time, the coffee was still too hot to drink by 7:45 PM. At this point, we uncovered the top and left it open. We checked the state of the coffee at 10:15 PM again. To our surprise, the coffee was still hot. Instead of calling it a day, we put the lid back on and left it overnight. At 8:30 AM the next morning, the coffee was still warm enough to enjoy every sip!

On the contrary, how long can it keep a beverage cool? A highlight feature of this mug is its wider opening. Big enough to fit full-sized ice cubes. We filled the cup with ice and water at 9:30 AM. The mug kept frozen throughout the day and night. The next morning at exactly the same time, we uncovered the water to find it still cold. Expectations exceeded yet again.

Cleaning: Not Dishwasher Safe

Unlike the Zojirushi Coffee Maker, their coffee mug is somewhat of a hassle to clean. It's not dishwasher safe, and the manufacturer even advises against using a cleaning brush. Hand washing it is required after use. Cleaning and maintenance is similar to a blender.

Price: Affordable Quality

This small coffee thermos comes at a very market competitive price. You get great quality for a reasonable price. Although the price is a little more than your usual "made in china" travel mug, you get what you pay for. Considering the fantastic features and top-notch quality, its price is very fair.

Other Features

Because of its compact design, it fits in most car and motorcycle cup holders. Also, this product comes with a five year limited warranty on the body.

Lastly, it's available in seven different color options.

In A Nutshell

Read on below for quick bullet points


• Dual-layered stainless steel construction that maintains the state of beverages

• Compact and easy to hold design

• Thoughtful design with a functional and helpful lock feature

• Exceptional performance in terms of insulation

• Fits well in most car cup holders

• Available in multiple colors to go with your style

• Available in two different sizes

• 5 year limited warranty


• Not dishwasher safe

• Parts need to be removed for a thorough clean up.

Final Thoughts

All said and done, this small coffee thermos is a winner just like the tried and tested Zojirushi Coffee Maker. Their travel mug passed all of our tests with flying colors. While too many parts may be a bit cumbersome to clean, its performance has won us over. With its dual-layered stainless steel construction, stellar insulation and reasonable price point, it is a must-have coffee mug for any frequent traveler!