The Best Food Thermoses

Insulated food jars for office lunches, camping, and road trips.

Our editors independently research, test, and recommend the best products; you can learn more about our review process here. We may receive commissions on purchases made from our chosen links.
Maxso Food Thermos

Madeline Muzzi

Whether you’re commuting to an office, heading out on a car trip, or spending the day at school, it’s always good to pack a snack or meal, and food thermoses are an ideal way to keep your food safe when you’re on the go. Storing cooked meals at room temperature for prolonged periods of time will allow bacteria to grow, so you want to make sure that whatever vessel you’re using will keep your food from lingering in the temperature danger zone (40°F to 140°F). 

I tested eleven insulated food jars for temperature retention, durability, and usability. My basic goal was to find a vessel that could keep food safe and ensure an enjoyable eating experience, even if you're on the go. That means no frustrating leaks, fussy cleaning procedures, or cumbersome accessories. These are the jars that stood out after measuring, snacking, and smacking them around. 

The Best Food Thermos: Stanley Adventure Vacuum Food Jar (18oz)

This Stanley insulated food jar was a top performer in both heat and cold retention. During stress testing, I dropped it directly on its included spork, and was shocked to see there wasn’t a scratch on it. 

The Best Food Thermos for Commuters: S'well Food Bowl (16oz)

The Swell 16oz insulated food jar tested well across the board. It was also the only food jar with a microwave-safe component. The prep bowl adds a lot of flexibility to this jar; you can either pack hot food and keep it hot, or pack cold leftovers from the fridge and reheat them when it’s time to eat. For those eating in an office or cafeteria with easy microwave access, this jar offers a convenient way to quickly heat up a meal without dirtying another dish. 

The Best Affordable Food Thermos: MAXSO Food Container (17oz)

Of all the jars tested, the MAXSO 17oz came in second for heat retention. It scored extra points for good looks and a user-friendly handle, and the relatively low price tag is equally appealing.

The Criteria: What We Look for in a Great Food Thermos

Food thermos with pasta and spork

Madeline Muzzi

A good food thermos should make your life easier.  At the very least, it shouldn't make your life harder. There are hundreds of options for jars online. They boast bold claims like “22 hours of heat retention,” and toss around words like “quadvac.” But we’re not distracted by bells, whistles, or marketing jargon. The most important factors here are safety, reliability, and durability. Those are the qualities that will make this product something you want to pack food in every single day. 

Safety is the core of a food thermos’s job. These products are designed to retain temperature. If it’s packed in the morning, the ideal jar should be able to keep food at a safe and enjoyable temperature until lunch.

Since they’re intended to be used on the go, a food jar also needs to be reliable in transport. A leaky container can easily ruin your day and your bag. It also shouldn’t be hard to clean or annoying to eat out of. 

Why You Should Trust Us

The products in this review were independently selected by Serious Eats editors, and rigorously tested during the writing process. Conservatively, I would estimate that I have packed 3,500 lunches in my day. I picked up the habit in elementary school because I refused to eat anything but tortellini with pesto, and I never stopped. Since then I’ve packed hot soups for ice fishing trips, cheese plates for summer hikes, and countless salads for days in the office. This review was designed with daily use in mind, and with the aim of finding the insulated food jars we’d truly want to use. 

The Testing 

Food thermos with pasta

Madeline Muzzi

After identifying the food jars, I ran each product through a series of tests designed to evaluate its safety, reliability, durability, and ease of use. The challenges were tough, there were multiple upsets, and not every food thermos made it all the way through. 

Test 1: Heat Retention 

All of the tested jars use the same basic temperature retention methods: double-wall vacuum insulation. They varied in thickness, dimensions, and coating material. They also varied in capacity. In the exact same conditions, a large volume of water will cool more slowly than a small volume of water. For the purposes of this test, I filled all jars with the same volume of food to even the playing field. 

To test for heat retention, I started with a classic lunch: chicken noodle soup. I filled each jar with piping hot soup, sealed the lids, and measured the temperature every two hours. 

All of the jars started with soup at 202°F. In a 70°F room, none of the thermoses that I tested were able to keep the soup above 160°F for six hours, but some came closer than others. The MAXSO food jar held its contents above 160°F for over two hours, making it the top performer on this test. The Stanley Master Unbreakable Food Jar, the Stanley Adventure, and the Zojirushi stainless steel jar also did well, falling only a few degrees behind the MAXSO. The Hydro Flask jar was disqualified after its contents dropped by over 50°F in just two hours.  

Test 2: Cold Retention

To test for cold retention, I used the same methodology that I used to evaluate heat retention, but instead of soup I used chilled chicken salad.

After starting at 34°F, none of the thermoses I tested were able to keep the salad below the food safe temperature of 40°F, even for two hours. Since all of the jars performed at a similar level, I decided not to disqualify them on this basis.

This was an overall disappointing round of testing, but there were a few notable results. The Stanley Adventure, the Zojirushi, and the 16 oz Thermos jars led the pack in cold retention. The Thermos Guardian was disqualified because I was unable to open it after the first seal. (I did every trick to try to pry it open, to no avail.)

Test 3: Leaking

To test for leaks, I filled the jars with boiling water, sealed them, and placed each on its side on a kitchen towel. Every two hours, I ran my hands over the towel to check for any moisture. Even a drop of escaped moisture would be grounds for disqualification. The Simple Modern jar was the only one that failed this test, and it failed spectacularly.

Test 4: Durability 

These jars promised to work in extreme conditions, and I wanted to see if they made good on that promise. 

Standing outside on a brick patio, I dropped each food jar from waist height three times and at various angles. To pass this test, the jars had to remain intact. I was willing to look past a few scratches, but any major dents were grounds for elimination. Even some of the toughest looking jars came out of this test substantially worse for wear.  The aluminum Chilly’s bottle ended up with large, thumb-sized dents. The Thermos fared slightly better, but still came away with a dented lid. 

Test 5: Washing and Overall Experience 

It doesn’t matter how well a food jar travels; if you dread cleaning it, you won’t want to use it. To evaluate ease of cleaning, I hand-washed each jar and ran the dishwasher-safe models through the dishwasher. For the jars with multi-part lids, I checked to make sure there were no hard-to-reach nooks. After washing, I sniffed for residual odors. 

I also held and ate out of each jar to evaluate them for comfort, and to make sure that I could reach the bottom with a spoon. In both of these tests, the wide-mouthed designs fared better than the tall and narrow options. The wide-mouthed jars were easy to reach inside for cleaning, and eating out of them felt like using a normal bowl. It’s more difficult to reach the bottom of a tall and narrow jar with a spoon and a sponge, which makes the eating and cleaning experience slightly awkward. Options like the Mira and MAXSO come with a lid that can be used as a bowl, which is an appealing option if you’re planning to use these somewhere without a stocked kitchen. 

How We Chose Our Winners

The winning food thermoses

Madeline Muzzi

After the testing was complete, a few jars stood out. None of the jars lived up to their claims for temperature retention, but our winners performed well. They also survived the stress tests, and distinguished themselves with useful extras.  

The Winners 

The Best Food Thermos: Stanley Adventure Vacuum Food Jar

Stanley Food Thermos

Madeline Muzzi

Stanley is a heritage brand that’s been making solid camping gear for decades. The Stanley Adventure food jar (also called the All-In-One) was a top performer across categories. It kept soup above 160ºF for over two hours, and bounced off the bricks with only the slightest scratch. It was one of the top performers in the cold retention test, but still failed to keep its contents at food-safe temperatures for two hours. For cold safety, pack this jar in a cooler with ice packs.

This jar jumped out of the pack with a never ending list of features.  The Stanley is basically a portable, dishwasher-safe picnic kit. It includes a spork, a lid that doubles as a bowl, and a loop for easy carrying. These features make it an appealing option for a car or camping trip when you don’t have easy access to a stocked kitchen. The only drawback is the design of the utensil holder: The spork attaches to the outside of the jar. While convenient, this placement doesn’t seem very hygienic. 

The Best Food Thermos for Commuters: S'well Stainless Steel Food Bowl

S'well food thermos

Madeline Muzzi

If you’re looking for a container to toss into a backpack or purse before heading out for the day, this S'well model has some considerable advantages. The smooth exterior won’t get tangled up with stray chargers, pens, or whatever else is in the bottom of your bag, and it won’t leak.

The thing that really sets this product apart is the prep bowl. The jar comes with an insulated outer bowl and a microwave-safe prep bowl. This might not matter if you’re camping or heading out on a car trip, but if you’re just hoping to pack a lunch, this is a big perk. You can pack hot food in the morning and keep it hot (the S'well food jar held soup at 160ºF for two hours), or you can pack cold leftovers straight out of the fridge. Once you’re ready to eat, take the prep bowl out, partially open the inner lid, pop it in the microwave, and enjoy a hot lunch. The bowl itself is easy to hold and eat out of. After your meal, cleaning is easy: The prep bowl is top-rack dishwasher-safe. 

That being said, the S'well jar isn’t the most rugged of our recommendations. After a particularly solid drop on the bricks, the external bowl rolled away with a slight dent. This might disqualify it for camping or road trips, but for daily use, the ease of cleaning and pleasant bowl shape set this model apart. 

The Best Affordable Food Thermos: MAXSO Food Container

Maxso food thermos

Something about the MAXSO insulated food jar is undeniably cute, but it didn’t coast by on good looks alone. Once all the test results were in, this charmer more than held its own. 

When it came to heat retention, the MAXSO came in second place. It was near the top of the pack in cold retention, but still fell below food safety standards for storage over two hours—if you plan on using it for cold food, use it with ice packs. After a thorough whack on the ground, there was no noticeable damage to the insulated bowl or lid. It isn’t dishwasher-safe, but it was easy to reach inside the shallow bowl and clean it by hand. 

When it came to using the jar in the wild, it didn’t disappoint. The built-in handle makes it easy to grab this jar and sprint out the door, even if your hands are full. This model includes a foldable spoon and a lid that doubles as a bowl.  (It’s also truly shaped like a bowl, with rounded sloping sides; it was a pleasure to eat out of.)

The inner lid is made of plastic. During cleaning, it took a bit of effort to wipe away grease. If not cleaned thoroughly, this lid may discolor over time. 

The Competition 

Chillys Bottles 16 oz: The Chillys Bottles 16 oz stainless steel food pot was sleek and attractive, but lost points because it dented easily when dropped. 

Hydro Flask 20 oz: The Hydro Flask 20 oz insulated food jar made the best first impression. It’s not too heavy, and the wide-mouthed design makes it easy to eat right out of the jar. Unfortunately, it was the lowest performer in both heat and cold retention tests. 

Thermos 16 oz: The Thermos 16 oz food jar is an overall solid product. It lost points because the rubber gasket became loose and snagged on the lid after the heat retention test, and because the lid dented easily when dropped. 

Zojirushi Steel Food Jar 16.9 oz: The Zojirushi food jar retained heat well and survived the drop test. Ultimately, the tall narrow shape made it slightly less practical to eat out of and to clean. 

Thermos Guardian 18 oz: The Thermos Guardian 18 oz was disqualified after the first round. The seal on the lid was so tight that I couldn’t get it open.  

Stanley Master Unbreakable Food Jar 17 oz: The Stanley Master Unbreakable food jar is a truly lovely product. It performed well in all categories. It lacks any of the additional features offered by the Stanley Adventure, making it difficult to justify the price tag.  

Simple Modern 16 oz: The Simple Modern insulated food jar was the top performer in heat retention, but leaked profusely when stored on its side. 

Mira 17 oz: The Mira 17 oz ranked toward the bottom of heat and cold retention tests. The mechanism holding the foldable spoon in place was faulty, and the spoon clattered to the ground each time I removed the lid.