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Updated Sep 2, 2022 6:54 AM

The best thermos is durable, easy to clean and, of course, keeps your drink warm (when you want it warm) and cold (when you want it cold) for hours on end. The thermos market has gotten trendy these days (thanks, YETI), and there’s a whole field of new products out there that all seem very similar. That’s mainly because the concept of a thermos is pretty damn simple: It’s a container with a vacuum between an inner and outer wall. The vacuum insulates the contents of the thermos and prevents heat from escaping. 

There’s not much for thermos makers to add from this basic concept, right? Not so fast. The cap’s design plays a role in how effective the thermos is. Some thermoses come with screw-on cups, handles, and others are compatible with aftermarket features. The best thermos hits that sweet spot between intriguing features and simple functionality.

To make my picks for the best thermoses I tested them for heat retention and durability. You’ll find the details of testing procedures at the end of this article. I also evaluated them on value, features, ease of cleaning, and testimonials from long-time users.

Read Next: Best Stainless Steel Water Bottle

Best Thermos Overall: Stanley Legendary Classic

Alex Robinson

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Key Features

  • Hot water test: 137 degrees @3hrs; 121 degrees @12hrs
  • Sizes: 20 ounces to 2.5 quarts (I tested the 1.1 quart version)
  • Materials: Stainless steel
  • Insulated 8 ounce lid doubles as a cup

Why It Made the Cut

My dad has carried the Stanley Classic thermos with him to his welding shop almost every day for 30 years. And, it’s been the iconic thermos for blue-collar workers and outdoorsmen and women for even longer. 

Pros

  • Screw-on cap doubles as a cup 
  • Useful, leak-proof nozzle

Cons

  • Plastic handle is susceptible to breaking (replacement handles are available)

Product Description

The Stanley Legendary Classic is the best thermos overall because it has a simple, timeless design that will keep your drink warm for a whole day. It took second in the hot water test behind the Thermos Stainless King (after 12 hours the Stanley poured water that was 121 degrees, and after 24 hours it was still hitting 104 degrees). Even better, this thermos will last you for years. 

One of the best features about this thermos is the screw-in nozzle, which seals tight and doesn’t leak. Plus, the classic cap doubles as a cup that many modern thermoses don’t provide. Both features are better designed than the similar Thermos Stainless King. The only downside of the Stanley Thermos is the green plastic handle, which will break if you smash it on a hard surface. But, you can easily buy replacement handles and cups. Sure, there are trendier thermos brands out there, but none make a better product than Stanley. 

Best Affordable: Thermos Stainless King

Alex Robinson

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Key Features

  • Hot water test: 139 degrees @3hrs; 123 degrees @12hrs
  • Sizes: 24 ounces to 2 liters (I tested the 40 ounce version)
  • Material: Stainless steel
  • Dishwasher safe

Why It Made the Cut

The Thermos Stainless King is the best thermos for anyone who wants a simple, useful, and affordable container to keep their drink warm. There aren’t any frills to this bad boy, and it’s about $10 cheaper than most other models in this lineup. 

Pros

  • Screw-on cap doubles as a cup
  • More affordable than other thermoses in this test

Cons

  • Plastic handle is susceptible to damage
  • Twist-and-pour stopper doesn’t screw down flush

Product Description

This basic thermos is about $10 cheaper than the others in the test and it performed the best in the hot water test. After 24 hours, water poured from the Thermos Stainless King was still a warm 106 degrees. The only thing that kept this thermos from winning Editor’s Choice was its plastic handle and plastic screw-in cap, neither of which were as nice as the Stanley model. If you’re looking for an affordable, everyday thermos that will keep your coffee warm for a full day, you won’t find a better buy than the Thermos Stainless King. 

Best Do-It-All Thermos: YETI Rambler

Alex Robinson

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Key Features

  • Hot water test: 132 degrees @3hrs; 95 degrees @12hrs
  • Sizes: 12 ounces to 2 gallons (I tested the 26-ounce version)
  • Materials: Stainless steel with Duracoat finish
  • Sturdy handle and spout

Why It Made the Cut

YETI has essentially defined its own drinkware category “Ramblers” through brilliant marketing and products that actually stand up to the hype (at least for the most part). 

Pros

  • Available in a ton of sizes and colors
  • Includes 5-year warranty
  • Variety of cap options 

Cons

  • Extra accessories are expensive

Product Description

The YETI Rambler is part thermos, part water bottle, and the smaller versions even serve as an oversized coffee mug. A buddy of mine, Mike Hunsucker from Heartland Bowhunter, uses a YETI rambler to keep burritos warm during long sits in the deer stand. He simply wraps them in tinfoil and then stuffs them in the rambler until it’s lunchtime. I tested the 26 ounce version, which is the size that I think has the most utility because it’s easier to throw in a pack—but if you really wanted to maximize heat retaining ability, go with a larger model. 

Best Thermos for the Environment: Klean Kanteen TKWide

Alex Robinson

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Key Features

  • Hot water test: 131 degrees @3hrs; 103 degrees @12hrs
  • Sizes: 12 ounces to 64 ounces (I tested the 32 ounce version)
  • Materials: Stainless Steel (90 percent recycled)
  • 5 additional cap options

Why it Made the Cut

The Klean Kanteen TKWide is the best thermos for the environment because it’s made of recycled stainless material. Also, Klean Kanteen is a certified climate-neutral company and a 1 percent for the planet member. 

Pros 

  • Made from recycled material
  • Additional cap options aren’t pricey

Cons

  • Additional caps are overly complicated

Product Description

This is a stout thermos with a simple, durable design. Unlike many other thermoses in this test it has a metal handle (instead of plastic) which I very much appreciate. The Klean Kanteen TKWide has a matte finish that looks sleek and is plenty grippy. It’s my pick as the best thermos for the environment because it’s made from recycled steel, and because overall, the company is climate neutral, which means it measures all of its greenhouse gas emissions and offsets those emissions by investing in carbon reduction and removal projects. Klean Kanteen also donates 1 percent of its sales to global conservation efforts. 

Best Thermos for Cold Drinks: Hydro Flask Wide Mouth

Alex Robinson

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Key Features

  • Hot water test: 100 degrees @3hrs; 65 degrees @12hrs
  • Sizes: 21 ounces to 64 ounces (I tested the 40 ounce version)
  • Materials: Stainless steel with powder-coated finish
  • 2 additional cap options
  • Lifetime warranty

Why It Made the Cut

Just ask any Gen Z kid: Plastic water bottles are out, the Hydro Flask is in. It’s probably a stretch to call the Hydro Flask a thermos (even though it does use the basic thermos design) because it’s really pitched as a high-end water bottle. If you’re searching for a functional bottle to keep your drink cool and make you seem cool too, look no further. 

Pros

  • Cap with drinking straw is great for cold water
  • Nice textured finish 

Cons

  • Took last in the hot-water test compared to standard thermoses

Product Description

This Hydro Flask fancy water bottle uses the same basic design concept as a thermos: an inner wall, vacuum, and outer wall. The outside of the bottle is finished with Hydro Flask’s powder coat, which gives the bottle a nice, grippy feel and makes it dishwasher safe. The version I tested comes with a straw lid (which is great for sipping cold water) but there’s also a Wide Mouth Flex Sip Lid available for anti-straw folks. Hydro Flask also makes a boot that stretches around the bottom of the water bottle. Overall, this is the best thermos for cold drinks. Cram this baby with ice and you’re good to go. One other cool thing about Hydro Flask is that it’s a non-profit organization focused on building, maintaining, and providing better access to parks. Since 2017, the organization has donated $1.9 million.

Best Lunch Thermos: Hydro Flask Insulated Food Jar

Alex Robinson

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Key Features

  • Hot water test: 117 degrees @3hrs; 72 degrees @12hrs
  • Sizes: 12 ounces to 24 ounces (I tested the 20 ounce version)
  • Materials: Stainless steel
  • Leak-proof seal
  • Lifetime warranty

Why it Made the Cut

The Hydro Flask Insulated Food Jar is the ideal container to keep your food warm until lunch time. It’s compact enough to fit in a backpack, it doesn’t leak, and it’s easy to clean (throw it in the dishwasher if you like).

Pros

  • Compact
  • Doesn’t leak
  • Easy to clean

Cons

  • Not the strongest performer in the hot-water test, but sufficient for lunches

Product Description

This handy food jar is the best lunch thermos because it will keep your soup, chili, spaghetti, or any other lunch item warm for at least 12 hours. The lid has a hefty, removable seal that prevents the jar from leaking. Since it’s removable, it’s also really easy to clean. The 20 ounce version I tested is an ideal size for stowing in a backpack for day-to-day use or trips into the woods. I’ll be using mine for days spent in the duck blind. But if you’re especially hungry around lunchtime, go for the 24 ounce version of the Hydro Flask Insulated Food Jar. 

Most Unique Design: OtterBox Elevation Growler

Key Features

  • Hot water test: 135 degrees @3hrs; 111 degrees @12hrs
  • Sizes: 10 ounces to 64 ounces (I tested the 36 ounce version)
  • Materials: Stainless steel and copper lining
  • 3 different lid options

Why it Made the Cut

The OtterBox Elevation Growler is a heavy-duty thermos made by a company known for making indestructible phone cases. 

Pros

  • Wide variety of sizes
  • Lid options are useful 

Cons

  • Plastic lid handle is susceptible to damage
  • The screw-on, pour lid costs $36 (the cost of another thermos)

Product Description

This is a solid thermos with some creative lid options. But first, the bad news: the standard screw-in lid has a plastic handle that could crack if you drop it on a hard surface during a cold winter day. The pour lid is cool, but it costs a cool 36 bucks. On the upside, the OtterBox Elevation Growler has an aesthetically pleasing design and a shape that makes it easy to hold on to. If you’re looking for a product that’s a little more unique than what the standard thermos companies are offering, well, look no further. 

Things to Consider Before Buying a Thermos

Think about how you’re going to use it and how you’ll carry it. If you want a thermos to ride in the cup holder of your truck or in the side pouch of a backpack, go with a smaller size. But if you measure your coffee intake by quarts, not cups, then go for one of the big boys. Once you’ve got the size nailed down, check out the pros and cons of the following products to pick the best thermos for you. 

How I Evaluated the Best Thermoses

Six of the best themos.
Figuring out the size and lid options you want is important in picking a thermos. Alex Robinson

The first thing I did with this field of thermoses was a hot water test. I heated a vat of water to 150 degrees (think super-hot coffee), filled each thermos, and screwed down the caps as tightly as I could. After three hours, I poured a cup of water from each thermos and took the water’s temperature with a digital thermometer. I repeated this after 12 hours. With the two biggest thermoses, I repeated once more after 24 hours. It’s important to note that the larger the thermos is, the longer it will retain heat. So, this isn’t a perfect apples-to-apples comparison. That said, you can compare the sizes and heat scores and make your own decisions. From there, I used the thermoses just as you would: I filled them up with coffee and brought them with me on hunts and daily outings. Lastly, I dropped each thermos from shoulder height over a concrete slab and then evaluated the damage. 

Overall, I evaluated each thermos on the following characteristics:

  • Heat retention
  • Durability
  • Price/value
  • How easy it is to clean
  • Cap and nozzle features

FAQs

We’ve got answers to your burning hot thermos questions.

Q: Which brand is best for a thermos?

There are a couple great brands to choose from. YETI has the overall strongest brand, and makes great products to back it up. If you’re looking for a classic, go with Stanley. If you want to save some cash, go with the Thermos brand. If you want to help save the planet, go with Klean Kanteen. One fact worth noting: all the thermoses in this test, and many (or maybe even all) of the thermoses not included in this test, are made in China. 

Q: Which thermos stays hot the longest?

Based on my hot water test, Stanley and Thermos keep water hot for the longest. But as I mentioned in the intro, the size of the thermos has a lot to do with that: the larger the thermos and the more liquid it holds, the longer that liquid will stay warm (it’s physics). That said, the YETI rambler also performed well, and the larger models will keep your drink and food warm for at least a day. 

Q: What should I look for when buying a thermos?

Look at the quality and design of the cap. This is where most heat is lost. All of the best thermoses are made from stainless steel and cost about the same amount. Essentially, it all comes down to cap design and function. 

The Upshot

There are plenty of great brands making high-quality thermoses. Don’t go with a cheap knock-off model. Any of the thermoses come in a variety of sizes and colors. Pick the best thermos that fits your style best, and never drink lukewarm coffee again.