Best Thermos

The Best Thermoses of 2021

If you want your favorite liquids to stay hot all day, check out our roundup of the best thermoses of 2021. Get ready to warm up with a hot drink.

Whether you’re heading out for a day of hunting, ice fishing, or enjoying the solitude of a winter trail, a warm cup of coffee or a hot lunch can make any weather a bit warmer. The perfect thermos will vary from person to person, but they all have overlapping qualities that make them the ideal piece of outdoor gear.

We narrowed down the best thermoses according to durability, leakproof-ness, heat retention, and overall capacity. If you’re looking for a water bottle, check out our lineup of the best insulated water bottles of 2020.

You can scroll through to see all of our recommended buys or jump to the category you’re looking for:

The Best Thermoses of 2021

Best Overall: Stanley Classic

Stanley Classic 2qt

You can’t quite beat a classic when it comes to a good thermos. The Stanley Classic ($20-35) has it in the name, and it’s been a top contender for thermoses since its release in 1913. There have been updates to the design since then, but one thing holds true: The vacuum insulation can keep liquids hot or cold for up to 32 hours and keep ice for 160 hours.

It’s a tad heavier than some of its counterparts on the market, but there are numerous reasons Stanley has been used for generations.

The handle on the thermos’ side makes it easy to carry and to pour, even while wearing gloves. The lid doubles as a cup, so if the contents are too hot to drink directly from the thermos, pour the contents into the lid to cool faster.

This classic Hammertone green thermos holds about 2 L of liquid. The good news is that no matter the size of the Stanley Classic you choose, it’s durable, won’t rust, and is BPA-free. Not only that, but if you close the lid correctly, you can guarantee that this thermos will be leakproof. That means no worries about tossing this bad boy into a pack on a hike.

  • Capacity: 1.9 L (64 oz.)
  • Weight: 2.2 lbs.
  • Pros: Leakproof, durable, well-insulated
  • Cons: Somewhat heavy

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Runner-Up: Thermos Stainless King 40 oz

Thermos Stainless King

Another widely known and trusted brand in the thermos world is Thermos. With a name like that, it would be hard to imagine anything but quality. The Thermos Stainless King ($30) is designed to function as a holder for hot or cold liquid. The brand has food-specific thermoses as well, but this 40-ounce thermos is the best coffee thermos in its line.

Thermos’ patented vacuum insulation keeps liquids hot or cold for 24 hours, and bottles are designed to keep the exterior temperature lower, making it easy to hold. This also prevents the bottle from sweating when holding cold liquids in the summer months.

As with other brands of thermoses, the Thermos King’s lid doubles as a cup. To make pouring easier and to maintain liquid temperature longer, Thermos integrated a clever twist and pour spout that lets you pour out the liquid without removing the stopper.

This stainless steel thermos is easy to use, BPA-free, and easy to keep clean by being dishwasher-safe. All in all, it may not have the highest heat retention, but it’s a top-quality pick, especially because of the additional functionality.

  • Capacity: 1.2 L (40 oz.)
  • Weight: 0.75 lbs.
  • Pros: Dishwasher-safe, easy-pour function, good heat retention
  • Cons: Lid cup and seal may need to be replaced after a few years

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Most Versatile: CamelBak MultiBev

CamelBak Multibev

CamelBak upped the ante with its MultiBev ($48) thermos design. This 2-in-1 thermos is both a thermos-style water bottle and an insulated travel cup. Unlike many other thermos cups that double as the lid, this thermos’ travel cup portion is the base, and it comes with a roll-up silicone lid.

The bottle lid of the CamelBack MultiBev does have a small compartment underneath the handle to hold the travel cup’s foldable silicone lid. If you don’t plan to use the travel cup’s lid, that compartment is big enough to hold a tea bag or a handful of nuts. This unique design seems to be most applicable for working people looking for travel coffee mugs that can also function as water bottles.

The thermos’ overall capacity isn’t that large, and it’s heavy for holding just over 20 ounces, making it hard to justify bringing with when snowshoeing or hiking. Still, it’s a durable design that keeps liquids hot or cold for extended periods and is perfect for sharing.

  • Capacity: 0.65 L (22 oz.)
  • Weight: 1 lb. 4.8 oz.
  • Pros: Well-insulated, versatile design, easy for sharing
  • Cons: Small liquid capacity, heavy for size

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Best Coffee Thermos: Contigo Travel Mug

Contigo Travel Mug

The best coffee thermos on our list is a low-profile mug that can do just as well on a hiking trail as it can day to day during your commute. Unlike the standard travel coffee mug, the Contigo Travel Mug ($13) is designed with a SnapSeal lid to make the seal leakproof and keep coffee hot longer.

The most popular size for the Contigo Travel Mug may seem small, but Contigo makes 16-, 20-, and 24-ounce size options. To further add to consumer design choices, Contigo gives you the option to have a handle, grip, or neither.

The high-quality stainless steel body is BPA-free and insulated well enough to keep liquids warm for up to 7 hours and cold for 18 hours. The lid is plastic, so be aware that sometimes the flavors may overlap if you drink tea and coffee in the same mug.

  • Capacity: 0.5-0.7 L (16-20 oz.)
  • Weight: 0.32 lbs.
  • Pros: Fits in most cupholders, multiple design options, decent heat retention
  • Cons: Should not put in a bag because the lid could open

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Best Thermos Mug: YETI Rambler Mug

Yeti Rambler Mug

The YETI Rambler Mug ($30) took all the benefits of a classic thermos and put them into a trusty coffee mug. This Rambler Mug gives cabin retreats and backcountry camping ventures the perfect start to any morning by ensuring your coffee stays hot and your tea is a continuously warm treat each night.

The 14-ounce mug is made from stainless steel, with a DuraCoat finish adding to the durability and preventing sweating when holding cold beverages. Because YETI designed this as a mug, the lid doesn’t provide a completely leakproof seal. However, the lid is perfect for fireside sipping and is tight enough to help liquids maintain temperature for 6-7 hours.

  • Capacity: 0.41 L (14 oz.)
  • Weight: 0.81 lbs.
  • Pros: Sweat-free, easy to use/clean, durable camp mug
  • Cons: Not leakproof, heat retention

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Best Food Thermos: Hydro Flask Food Jar

HydroFlask Food Jar

Nothing beats a hot lunch on a cold day out in the backcountry. But if you’re not lugging in a huge thermos, how will you get your soup out there? The Hyrdo Flask Food Jar ($35) solved that problem by being a functional, compact container made specifically for food, not just liquid.

The TempShield double insulation keeps your soups or stews hot for hours. It isn’t just ideal for cold weather, though. The container is a perfect size for a fresh fruit salad in the summer. It’s fully leakproof when closed correctly, making it a packable container for any trek.

Unlike bringing soup in a standard thermos, the Hyrdo Flask Food Jar is designed more like a bowl to provide a wide-mouth opening for ease while eating. With the stainless steel materials, you don’t have to worry about flavor transfer into the container.

  • Capacity: 0.35 L (12 oz.)
  • Weight: 0.7 lbs.
  • Pros: Lifetime warranty, compact, lightweight, durable, heat retention
  • Cons: Small food capacity

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Best Thermos for Soup: Maxso 2-Pack

Maxso 2 Pack

Maxso insulated thermoses ($37) are the perfect lunch companion for soups on and off the trail. The size and functionality of each of the thermoses can give you the confidence to store these anywhere in your pack or lunchbox.

They’re both vacuum-insulated to keep food hot for up to 12 hours and cold for 24 hours. The top lid doubles as a bowl for eating, and the air-pressure-sealing lid secures the food within the thermos. With an updated design, a foldable spoon fits into the sealing lid.

There’s one larger and one smaller thermos in the two-pack, and it comes with one foldable spoon. The containers are designed with a nonslip bottom and an easy-open air-pressure system that even your kids could get used to using correctly. For the price, these are excellent thermoses for soups and drinks alike.

  • Capacity: 17 oz. & 24 oz.
  • Weight: 2.1 lbs.
  • Pros: Integrated spoon, nonslip design, heat retention
  • Cons: Only one spoon included, difficult to clean

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Best Thermos for Kids: Simple Modern Insulated Bottle

Simple Modern Insulated Bottle

If you bring your kids along for outdoor adventures or they need a new thermos for school, the Simple Modern Insulated Bottle ($17-40) is an extremely functional design. The 14-ounce bottle is small enough for them to carry themselves and for most kids to easily handle.

It’s useful for holding cold liquids for hours, and your kids won’t have to worry about opening and closing the top because it has a straw. The straw makes it easy for kids to drink, with no tilting necessary. It’s leakproof when the straw nozzle is in the closed position, so be sure that it’s closed all the way before putting it in a pack.

The only downside to these insulated bottles is that they’re meant for drinking cold beverages; they aren’t designed for hot liquids. Because of the design, the heat causes pressure that could make the bottle leak or spill.

  • Capacity: 14-84 oz.
  • Weight: Varies
  • Pros: Straw nozzle, handle on lid, multiple size options
  • Cons: Not intended for hot liquids

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Best Food Thermos for Kids: Thermos Funtainer

Thermos Funtainer

Utilizing the classic Thermos design, just in a smaller package, the Funtainer is perfect for kids. The Funtainer ($15) is a 10-ounce food jar for kids to pack in a lunch and is available in multiple designs and patterns. It will keep food cold for up to 7 hours or hot for 5 hours while keeping the container’s exterior cool enough for your kids to handle.

The Funtainer has an extra-wide opening for food to make it easy for kids to eat directly from the food container. They’re still vacuum-insulated and use BPA-free materials, making them leakproof and easy to clean.

If you pack a school lunch for your kids every day, this thermos’ size is perfect for a lunchbox, so there’s no need to pack a thermos outside away from the rest of the food. Just note that it won’t regulate hot food temperature well if put in a lunchbox with an ice pack.

  • Capacity: 10 oz.
  • Weight: 0.5 lbs.
  • Pros: Wide-mouth opening, lightweight, leakproof
  • Cons: Heat retention, seal may need replacing

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Buyer’s Guide: How to Choose a Thermos


Determining your thermos’ capacity comes down to two factors: the intended activity and if you’re sharing.

If you’re heading out for a day of ice fishing, lugging out a Stanley classic will be no issue, but if you’re embarking on an ultralight backpacking trek, a thermos may not even make the cut.

Consider how much you usually drink or eat and if it will fit inside of the thermos container. Jumping off from there, decide if it’s just for you or if you’re packing lunch or coffee for you and your partner. If you have multiple people sharing a thermos, then a larger capacity is ideal. However, if one cup of coffee is all that’s needed, something closer to the CamelBak MultiBev will suffice.

Stanley Classic


The insulating capabilities of a thermos are what makes them so useful. Most thermoses on the market today will utilize vacuum insulation, but some may also use foam insulation. Vacuum insulation tends to work better than foam, making it the standard for quality thermos brands.

Vacuum insulation essentially uses a double layer of material to create a space between the walls. This gap of air (the vacuum) is what prevents heat from escaping or entering.


Most of us bring our thermos outside for some reason or another, so it needs to be able to take a beating. Top-quality thermoses are constructed using stainless steel of some kind, at least for the thermos’ body. A stainless steel body is harder to break, especially in cold conditions.

Many thermoses also have an additional coating to ensure it’s well-protected. Be mindful of the handle and the lid when considering durability as well. Many thermos lids have stainless steel exteriors, and the air-pressure lid is plastic because it isn’t directly exposed unless opened.

Some other thermos designs have all-plastic lids, and this is usually the first part of the thermos to fail. If it does come with a plastic lid, double-check the warranty or if replacement parts are available if something breaks.

YETI Rambler

Lid Construction: Leakproof & Drinking-Friendly

Another aspect of the lid to consider is the seal and how you drink out of the thermos. If you have a food-specific thermos, then consider how easy it is to pour from the opening as well.

Traditional thermos designs have two lids: one air-locking lid and an exterior lid that doubles as a cup. These dual lid designs are almost always leakproof, especially because both lids have a rubber seal of some kind. Having a secure lid design is necessary when carrying around a thermos of hot water or coffee — not only to prevent spilling in a bag but also for your safety.

Other thermos lids, like that of the Contigo Travel Mug, are more like a travel coffee container lid. So they should have a rubber seal and a variation of Contigo’s SnapSeal to cover the drinking spout. These lids will vary from company to company, but be sure to pay special attention to how well the lid seals, especially if intending to use backpacking.

If you’re only using the thermos as a food container, then look at the opening of the lid or top of the thermos to see how easy it will be to pour. The wider the mouth, the harder it will be to be precise when pouring. However, a wide mouth can be easier to eat directly from the thermos.

When a thermos is meant for drinking, then the lid construction determines how easy it is not to spill on yourself with every sip. Silicone lids usually create a decent seal but can be challenging to drink from. Plastic lids with a sipping hole or straw are usually the go-to for most nontraditional thermos lids.

Extra Features & Accessories

Extra features like a lid that doubles as a cup, the handle design, grip, or a built-in spoon add a bit of versatility to a thermos. These aren’t necessary aspects of the thermos that make or break the functionality, but they can add that little extra piece that makes your life easier or a little more comfortable when enjoying coffee or tea on a cold winter morning.

Thermos Accessories


What Are the Best Thermos Cups?

As far as temperature control goes, the best thermos cups are designed by YETI or Hydro Flask. Both companies have mugs and cups that don’t utilize the traditional thermos air-pressure seal and instead have an insulated cup with a sipping lid. These aren’t spill-proof, but they afford the consumer the insulation of a thermos in cup form.

How Can I Best Clean a Thermos Flask?

Some thermos flasks can be cleaned in a dishwasher, but not all of them are dishwasher-safe. This is disclosed according to the manufacturer of the thermos. If it’s not dishwasher-safe, be sure to take the thermos apart completely and handwash after every use. Don’t forget to remove the rubber seal within the lid to ensure no food or liquid is trapped under it.

Which Thermos Stays Hot Longest?

Stanley thermoses classically have the best heat retention compared to any other brand. This is due to their quality materials, vacuum insulation, and tight lid seal. However, to create a thermos with the best heat retention, it did have to be bulkier and heavier than the others.

Have a favorite thermos we missed? Let us know in the comments below for future updates to this article.

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