After doing close to 50 hours of research over three years, as well as looking at last year’s pick alongside more than 60 competing travel mugs and testing it against 20 of them for heat retention, usability, and durability, we still believe that the Zojirushi New Stainless Mug offers the best balance of heat retention and versatility. In our latest round of testing, after a full eight hours the coffee we kept in it was nearly as hot as the coffee we had in the previous version of the container and 26.2 degrees hotter than the next-best mug in our test group—just enough to make the difference between drinkable and lukewarm.
*At the time of publishing, the price was $26.
The 16-ounce Zojirushi New Stainless Mug is at the higher end of the cost spectrum. But its well-designed exterior, one-handed usability, easy-to-clean nonstick Teflon interior, and foolproof locking mechanism are well worth the price of admission. This mug will never, ever spill in your bag. It’s hard to put a price on that sort of thing (well, actually, it’s about the price of a new bag, laptop, phone, and whatever else happened to be in there at the time).
We’ll be talking a lot about Zojirushi’s travel mugs in this guide. Unfortunately, although the company makes some excellent products, it isn’t so great at choosing names for them. To keep things from getting confusing, we’ll be referring to the SM-SA48, SM-KHE48, and SM-YAE48 mugs as the New Stainless Mug, Original Stainless Mug, and Travel Mug, respectively.
*At the time of publishing, the price was $26.
It has sturdy, leakproof seals and a simple locking mechanism that we trust to keep our belongings dry. It’s easy to use one-handed, too. During our testing and everyday use, it didn’t leak, didn’t spill, proved to be pretty tough, and took a bit of a beating. It also has an attractive design that’s minimalistic yet eye-catching in its simplicity. Over the two-plus years since we first profiled this mug, on Amazon it has garnered an overall rating of 4.8 stars (out of five) across more than 2,500 reviews, 88 percent of which awarded five stars.
Zojirushi’s stainless steel mugs have continued to dominate the competition in our heat-retention tests. We filled the New Stainless Mug with water heated to 201.5 degrees Fahrenheit—a level within the range of the ideal brewing temperatures for a good cup of coffee—and left it to cool over an eight-hour period, testing the water’s temperature every two hours. At the end of the test, the water inside the New Stainless Mug was still 151.2 °F—a decrease of 50.3 degrees. That means you’re getting drinkably hot 150-degree-plus coffee eight hours after brewing. The only mug capable of besting this result was Zojirushi’s Original Stainless Mug, which allowed for a total temperature loss of 46.3 degrees—a difference of 4 degrees. Despite this data, we prefer the New Stainless Mug over the Original Stainless Mug for a number of reasons.
While the Original Stainless Mug provided marginally better heat retention than the new version, it weighs 1.6 ounces more (about the weight of two AA batteries). That excludes the weight of any beverage you might put in it. Although this amount might not sound like much, ounces add up to pounds, and for anyone commuting with a travel mug in a bag along with a laptop, a lunch, and perhaps a change of clothes for the gym, heft matters. After consulting with some of our editorial staff on the issue, we decided that the New Stainless Mug’s lighter weight was worth trading away a few degrees of heat retention.
In addition to its lighter weight, the New Stainless Mug features a more compact lid design that, when popped open, obscures less of your view when you tip the mug to your mouth to drink. As with the Original mug, the lid locks and unlocks when you press a button, allowing you to drink from it easily without looking. But on the New mug, the size of the lid latch has been reduced, making for more comfortable drinking—no longer will you find yourself jamming your lower lip into the locking mechanism.
Both the New and Original mugs have a secondary locking mechanism designed to prevent spills. Just flip the secondary lock into position, and you’re guaranteed that the top won’t pop open when you don’t want it to. We feel very comfortable putting this mug into a bag with our valuables and letting it roll around on its side or upside down without any consequences. Although other mugs, such as the Contigo West Loop and the Cozyna, have a similar mechanism, we found them more difficult to use one-handed. The locks on these mugs weren’t dealbreakers, but they were less convenient to use than just flipping a switch on the Zojirushi mugs.
It’s easy to clean the New Stainless Mug with a quick rinse, using some soap and occasionally a bottle brush when necessary. The nonstick fluorine interior helps to prevent odors and stains. (These are fluoropolymers of the sort used in Teflon—if you prefer drinking from a vessel that doesn’t have a nonstick coating, check out Zojirushi’s Original Stainless Mug.) And unlike with some of its competitors, such as older-style Contigo mugs, you can completely disassemble the plastic lid to clean out any smells or gunk that might get lodged in hard-to-reach places.
The New Stainless Mug is durable. It did develop a few scuffs after our drop tests, but not any more than the other options we tried. In the off chance that any of a mug’s parts gets damaged or wears out, Zojirushi is generally good about providing replacement parts. Additionally, Zojirushi backs the vacuum insulation of its stainless steel mugs with a five-year limited warranty.
Unlike most of the other companies that we looked at, Zojirushi offers its travel mugs in a number of sizes. In addition to the 12-ounce and 16-ounce sizes that the Original Stainless Mug is available in, the new version is also sold in a 20-ounce capacity.
Although we didn’t place much emphasis on keeping cold liquids cold for this guide—check out our water bottle guide for what’s best in that regard—we did find that the Zojirushi New Stainless Mug retained cold better than all of the other mugs in our testing lineup.
Over a period of eight hours, this mug allowed our icy-cold 33 °F water to warm up by only 4 degrees, while the other mugs in our test group allowed the temperature to rise considerably more over that time. So if you’re looking for a dual-use container that can preserve both hot and cold well, the Zojirushi New Stainless Mug can hold its own—especially considering that it’s available in a larger, 20-ounce capacity. Just be aware that its narrow opening is less than ideal when you’re trying to quench your thirst after cresting a tall hill.
Our only major complaint about the Zojirushi New Stainless Mug is that it’s actually a bit too good at insulating sometimes. We’ve found that if we make a fresh pot of coffee and pour it directly into the travel mug, the liquid ends up staying mouth-burningly hot for hours. Let your beverage cool a little before closing the lid.
Another small complaint is that this mug is a bit skinnier than your typical travel mug, which means it may not be a snug fit in a car cup holder or bike water-bottle cage. If you prefer a travel mug with a greater circumference, check out the Contigo mug.
On a similar note, both the Original and New stainless steel mugs have a notably narrow opening. This design is good for preventing burns from potentially scalding coffee or tea, but it makes either mug less than ideal for use as a day-to-day water bottle or for people who like to gulp down their beverages. You could always remove the lid entirely, but that kind of defeats the purpose of the mug’s ease of one-handed use.
Finally, at a typical price of around $30 for the 16-ounce size, the Zojirushi New Stainless Mug is on the higher end of the price range for a travel mug. But it’s worth the handful of extra dollars over the competition because of the container’s superior construction and performance.
After constant use for close to three years, our pick retains heat just as well as on the day we got it. Although cleaning in the dishwasher is not advisable for double-walled stainless steel (see the Care and maintenance section below), this mug has survived several accidental trips through the dishwasher without any noticeable decrease in performance. It has also traveled in many crowded bags, backpacks, and purses without any leaks.
Due to a number of superficial scrapes and scuffs, it’s no longer as pretty as it once was, but its having survived the occasional fall reassures us that this is a truly solid mug, and we have no qualms continuing to recommend it.
But this Contigo model does have drawbacks. First, it won’t keep your beverages hot for as long as our top pick. At the two-hour mark, the contents of the Contigo mug had cooled to 149.5 °F. That’s 1.7 degrees lower than the temperature of our main pick after eight hours. In its eighth hour of testing, the water inside the Contigo measured a lukewarm 108.6 °F.
Then there’s the build quality. This mug feels sturdy, and in a few weeks of testing, its button-activated locking spout didn’t leak. But the lid has a lot of plastic parts inside that make its spout open, close, and lock, and according to a few Amazon reviews, these pieces can wear down after one to two years of regular use, or sooner if you’re too rough with them while cleaning the lid. Contigo sells replacement lids for $7. If you add a replacement lid in, it’s still less expensive than our main pick. But if you consider the cost of repairing or replacing anything potentially ruined by a leak in your bag, the Zojirushi is probably a better deal. We’ve also read complaints about the colored coating on the exterior of the mugs chipping off over time. But that’s something we’ve seen with other mugs, too, so the problem is not unique to the Contigo model.
Last, despite adjustments to its design, the Contigo Autoseal West Loop’s lid is not as easy to clean thoroughly as the Zojirushi gear is. Contigo did improve its design for this version of the mug by exposing the lid’s spout mechanism, but you still can’t take the lid apart completely (whereas you can with our main pick).
If you can’t find Zojirushi’s New Stainless Mug, or if you prefer to drink from a mug that has an electro-polished stainless steel interior (instead of a nonstick coating, like our main pick), get Zojirushi’s Original Stainless Mug, our previous pick for this guide. It costs about the same as the New Stainless Mug, and it will keep your drinks a few degrees hotter over the long term. However, it weighs a little more than our main pick, has a bulkier lid that’s not as pleasurable to drink from, and doesn’t come in a 20-ounce size.
We also considered the Zojirushi Tuff Mug, which is similar to the Zojirushi Original Stainless Mug in design and functionality. The Tuff Mug performed exceptionally well in our heat-retention tests (it basically tied with the last-generation Stainless Mug), but we gave it the boot because of usability issues. The Tuff Mug has a completely removable top lid and a difficult-to-understand drinking mechanism. We handed it to several very technical friends to mess with, and no one could figure out how to make the liquid come out at first blush. Having separate parts means you have more things to lose when you’re out and about, and confusing usage means danger for anyone trying to keep their eyes on the road. You also can’t completely disassemble the top, so it might harbor smells or gunk later on.
Zojirushi brought its latest Travel Mug (SM-YAE48) to North America in the fall of 2015. This 16-ounce mug costs a little more than our main pick and runner-up. It comes with an electro-polished interior, like the Zojirushi Original Stainless Mug, with a shape that’s stouter than other Zojirushi mugs and short enough to fit under the spout of a single-cup brewing machine. Its insulating performance is worse than that of our pick, however: After eight hours, the water temperature had dropped to 122 °F, ending up 29.2 degrees cooler than our main pick. This may have happened because its plastic lid has a significantly larger surface area, which loses more heat. The bigger lid also obscures your view as you drink (not good for use while driving).
Lots of folks prefer to drink hot beverages from glass, so we tested Lifefactory’s 16-Ounce Glass Mug with Cafe Cap. It comes with a soft silicone wrap to help protect the glass from damage, plus a push-button lid that’s designed to keep liquids from leaking out. We looked past the fact that the mug is made to keep drinks hot for only about an hour—but we couldn’t overlook the fact that this Lifefactory mug failed our overnight leak test.
In a previous version of this guide, we recommended the OXO Good Grips LiquiSeal Travel Mug. But in the time since we first tested the LiquiSeal, we’ve found a number of customer complaints about the mug: Its open/close mechanism is prone to failure over time, its lid mechanism is almost impossible to clean, and the chunky size of the mug, while great for some cup holders, makes it a poor choice for stuffing into a purse or a briefcase. And it costs more than our main pick, which doesn’t have any of these issues.
The Klean Kanteen Insulated Wide was our top insulated water bottle pick for most of 2016 and early 2017, and was a runner-up in this guide. Originally this bottle had a café-style lid that tended to leak, disqualifying it as a travel thermos. Klean Kanteen updated the lid in 2016, and initial testing made us confident it could spend a day bouncing around inside a purse without spilling. However, more comprehensive testing in the summer of 2017 for our guide to water bottles found that the lid occasionally leaks if left overnight and can also limit the flow of your drink. Therefore, we’ve removed it as a pick.
We considered testing the CamelBak Forge travel mug. It costs a little more than the Contigo Autoseal West Loop, and like the Contigo, it allows one-handed opening. It’s available in 12-ounce and 16-ounce sizes, and unlike older CamelBak travel mugs and water bottles, its lid is designed to be easy to clean. However, we found a number of owner complaints regarding the build quality of the mug, including claims that its push-button mechanism is difficult to use and that the mug frequently leaks.
We wanted to look at the Joeveo Temperfect mug—a model that purportedly uses a special insulating material to capture excess heat energy and then releases it over time to keep your beverage at an optimal drinking temperature. It was supposed to be released in 2014, but due to production issues, its release got delayed to the first half of 2016; these days, Joeveo says it will ship current orders in early 2017. If we can get our hands on one, we’ll take it for a spin and let you know what we think.
We had high hopes for the Cozyna Vacuum Insulated Stainless Steel Travel Mug, a 16-ounce container that takes its design cues from Zojirushi, with a similar lid that comes apart for cleaning. However, upon receiving it, we found that the lid’s locking mechanism jutted out from the surface of the mug—if the mug were stuffed in a bag with anything else, the lock and latch could be pushed and opened accidentally. Plus, the mug arrived without an internal rubber stopper, making it possible for liquid to pour out as soon as the container was upended. As such, we had to disqualify the Cozyna, at least for the time being. We’ll test it again once we’re able to obtain a mug that comes with all its parts.
The Timolino Icon Vacuum Travel Tumbler (PCT-46KM) is a 16-ounce tumbler-style travel mug with a flip-up lid and an electro-polished interior. We liked the look and feel of the Icon, but every time we flipped the lid open to drink from it, a small amount of liquid splashed out of the opening and off the spout’s rubber stopper. Plus, it failed to keep beverages as hot as any of our three main picks.
We love the look of the 16-ounce Stanley Classic One-Hand Vacuum Mug. It resembles an old-school vacuum bottle but has a modern button-activated lid that makes it easy to drink from one-handed. In our tests, this lid mechanism, which comes apart easily, was a cinch to clean. However, after screwing it apart the first time, we found plastic debris in the threads, which prompted concerns about the mug’s long-term durability. In addition, despite costing a few dollars more than our main pick, it was unable to keep beverages as hot—the Stanley’s eight-hour temperature reading was 125.1 °F versus our main pick’s 151.2 °F.
In our test group, the container that was the most like Zojirushi’s stainless steel mugs was the Thermos Nissan Stainless Steel Commuter Bottle. The design is almost exactly the same: a double-walled, stainless steel bottle with a screw-on top that has a button you can push to pop it open and a separate locking mechanism for when you throw it into a bag. In the first round of tests for this guide, it came in third place after the Zojirushi mugs and was the only other bottle in our lineup that kept coffee at barely above lukewarm temperature after eight hours. The main reason it lost out to the Zojirushi is that the secondary locking mechanism, which is just a metal loop that fits over the front of the lid, can be finicky for anyone who has ham hands (such as myself) or anyone who might be fiddling with it while driving.
We also tested the Thermos Vacuum Insulated Travel Mug (with tea hook). While we liked the look of it, the heat retention was just so-so—it was able to keep coffee at or above optimal drinking temperature for only about four hours—and we found the tea hook to be unnecessary. (Some people use these containers for tea, but most of the time they just plop the tea bag into the bottle without any problem.) This Thermos mug also has a push-button interface: You press the button on top when you want to drink and press again to seal it when you’re done. But it can be confusing to determine whether the button is in the up or down position just by looking at it, so you may find yourself pressing it over and over again to figure out whether it’s open or closed.
The Thermos Vacuum Insulated Stainless Steel Travel Mug costs as much as our main pick and runner-up, and it comes with a grippy handle that makes drinking out of this mug a pleasure. Unfortunately, that same handle sticks out so far that attempting to jam the mug into a backpack is a pain—a fact that Thermos must realize, as the mug comes with a carabiner for attaching it to a travel bag or pack. Plus, eight hours after we poured boiling water into it, this Thermos mug’s contents were close to 7 degrees cooler than the water in the Contigo West Loop mug (which costs far less). Finally, this mug has a twist-off opening, which is impossible to use one-handed.
We also tested a previous 16-ounce version of the Contigo Autoseal West Loop that the company then discontinued as of March 2015. This Contigo model was clearly designed more as an active drinking vessel than as something you’d throw in a bag to drink later at work. It was wider, so it fit more securely in a cup holder, and it had a one-button interface, which meant you could easily take a sip without having to look at it. The downside here was that it had about the same level of heat retention as the OXO LiquiSeal (which is to say, not very much). This Contigo mug was able to keep our coffee above lukewarm for only one to two hours; that might be fine if you make your coffee at home and drink it while driving to work, but such a mug isn’t particularly versatile for other situations. In this case, we happened to like the OXO LiquiSeal’s drinking button better than this Contigo’s, though in reality the two could almost be interchangeable.
We also had several other models that came under consideration but didn’t place in our final tests. For example, there’s the Contigo Extreme mug, which Good Housekeeping says can obscure your view when you’re drinking—bad for drivers—and can be uncomfortable to sip from.
Bodum makes a combination French press and travel mug that sounds appealing: You can literally brew your coffee inside the mug as you take it with you. In reality, though, the process is not much different from brewing the coffee first and pouring it into the mug (in fact, it might be worse, because the Bodum will keep your coffee grounds in contact with the hot water for much longer, therefore changing the flavor and making it more acidic). Additionally, as anyone familiar with French presses knows, it could leave you with coffee-ground bits floating around in your coffee.
We got some requests to look at the Hydro Flask, so we did. This model is not as good as the other mugs we saw, let alone our top pick. It maintains heat at a drinkable level for only a handful of hours (four or less), and the drinking lid can’t lock, so it’s at risk of flipping open, potentially spilling everywhere—a fact that the company’s own website points out. We would definitely not risk putting it in a bag, and we would be very careful about even dropping it or knocking it over.
Travel mugs tend to come in three basic materials: plastic, glass/ceramic, or stainless steel. According to previous tests performed by Cook’s Illustrated (subscription required), all-plastic mugs can’t retain heat for more than an hour, and all-ceramic ones can do so for no more than 30 minutes. Good Housekeeping agreed, stating that plastic and ceramic mugs don’t retain heat for long and break easily. That wasn’t acceptable to the Good Housekeeping testers—or to us, so in our research, all-plastic and all-glass mugs were out (although we did look at an all-glass mug this year, as we know that some people prefer drinking from a vessel made from the material despite its shortcomings). In the end, when you look at various other guides that have been written on the subject, including an extensive heat-retention test performed by Tested, the mugs that rise to the top are always double-walled, vacuum-insulated, and stainless steel.
Occasionally, travel mugs come with a stainless steel exterior and a ceramic or glass interior. This option tends to be better for people with sharp palates—those who can taste (and care about) a change in flavor when they’re drinking coffee directly out of a stainless steel container.
As such, it would seem easy to assume that coffee experts would never use or recommend a container with an unlined stainless steel construction, but that would be wrong. The problem with glass or ceramic interiors is that they can break easily—one wrong drop or bump, and your investment is in bits on the floor. This was a common problem among the mugs we researched in this category, and few people are happy after spending money on something that breaks. Besides, a growing number of mugs lined with stainless steel (including our runner-up pick) now come with electro-polished interiors, which makes the steel less likely to retain strange odors and flavors. That’s why our experts recommended sticking with stainless steel for its durability and insulating capabilities—and if you think you can taste a metallic flavor, try pouring the coffee out into an open-air mug before drinking it.
Some people actually prefer stainless steel interiors. According to Tested’s former editor in chief Will Smith, who performed his own extensive tests on insulated travel mugs, a container with a stainless steel interior is easier to clean and remove the coffee taste from if you want to use the mug for anything else (water, tea).
Regardless of palate sophistication (or lack thereof), our experts and research agreed that a vacuum-sealed travel mug made entirely out of stainless steel (save for the lid) was the best choice for most uses. Stainless steel retains heat the best out of all the available materials and is the least breakable, a double win.
Despite limiting our focus to all-stainless models, we still had hundreds of options to consider. So we turned to a number of publications to see what they liked the best and which criteria they used. The best guides on the subject that we found are the previously mentioned ones by Tested and Cook’s Illustrated, plus another one from Good Housekeeping, each of which took a slightly different angle on evaluating travel mugs. We also considered the most highly rated mugs on Amazon. From there, we focused on models that were highly ranked for heat retention and ease of use, taking extra care to select those that would be easier to clean, as well.
Using these criteria, we narrowed our list of test candidates, which included models from well-known names such as Bodum, Hydro Flask, OXO, and Snow Peak, down to 18. From there we quickly thinned the group down by close to half, taking into consideration build quality, whether the lid could lock for storage in a bag or purse, availability, cost, large numbers of reviews stating that the mug was far from leakproof, and whether the mug allowed easy one-handed use—an important factor for anyone looking to drink their beverage while they drive.
In the end we decided to call in eight mugs to test ourselves in 2015: Zojirushi’s SM-SA48, SM-KHE48, and SM-YAE48; the Contigo Autoseal West Loop; the Cozyna Vacuum Insulated Stainless Steel Travel Mug; the 14-ounce Thermos Vacuum Insulated Stainless Steel Travel Mug; the 16-ounce Timolino Icon Vacuum Travel Tumbler (PCT-46KM); and the 16-ounce Stanley Classic One-Hand Vacuum Mug.
To eliminate travel mugs as quickly as possible from our test group, we started by testing to see if they were as leakproof as their manufacturers said they’d be. We filled up each of the travel mugs with hot water and blue food dye, laid them down on a bed of paper towels, and left them overnight. When we checked the next morning, we disqualified any bottle with a blue stain on the paper towel underneath. We then conducted the same test with each bottle standing upended on its lid overnight.
Next we investigated how well each travel mug could maintain the heat of the liquid inside. According to 2012 US Barista Champion Katie Carguilo, as well as the Cook’s Illustrated findings, coffee (and black tea) typically brews at about 200 °F, and the best temperature to drink is at roughly 145 °F to 155 °F. We’ve seen some debate over the technical ideal when it comes to the temperature for coffee drinking, but we used Carguilo’s guidance to perform our tests. Subjectively, when it came to drinking temperature, 155 °F came off as a little too hot for our liking (but was still drinkable), whereas coffee seemed quite pleasantly hot down to about 140 °F. Anything below that started to feel lukewarm.
We heated enough water to fill all of our test bottles at the same time, sealing their lids once the temperature of the water in each mug dropped to 201.5 °F. We checked on the temperature of each of the mugs every two hours over an eight-hour period, charting the heat loss on a spreadsheet.
We also tested the durability of each mug by dropping them all several times.
Another important criterion that isn’t easy to measure objectively is one-handed ease of use. If you’re going to be using your mug while driving or biking (not that we recommend doing so), you’ll definitely need at least one hand free, and probably both eyes. A good mug should be easy to both open and close, as well as to lock and unlock, with one hand without your having to look down.
When you’re hand-washing your mug, most of the time dish soap and water will do the trick (although sometimes using some baking soda and vinegar is a good idea, too). Regardless of the mug design, you’ll need a few sizes of bottle brushes to clean in and around the lid mechanism, the spout, and deep into the vacuum bottle itself.
If your mug comes with silicone seals, like the ones on our Zojirushi pick, you’ll likely notice that over time they’ll take on the smells of what you drink from your mug. To remove the stink from your seals, bury them in fresh baking soda for two days.
We found that the best bottle-cleaning set out there is the OXO Good Grips Water Bottle Cleaning Set. It comes with a large bottle brush, a skinny straw brush, and a looped detail-cleaning brush, all kept together by a handy ring so you won’t lose any of the parts. The set is dishwasher safe, and it barely has any one-star reviews on Amazon, so it’s a pretty good bet for anyone looking to get gunk out of their hard-to-clean items.
(Photos by Michael Hession.)
The key's under the mat.