Buying Guide: Best 5 Thermos Flask Products

It is the simple joys in life that make it worth living. Like the joy of enjoying a hot beverage on a chilly morning while watching the sunrise. Having a way of keeping your coffee, food or soup hot until you need it, is an unparalleled joy.

Thermos flasks have been around since the early 20th century, and their products have been distributed to every corner of the world. To this day, Thermos is still making vacuum flasks.

Insulated flasks operate on one basic principle: keep liquids hot or cold. They have double walls separated by a vacuum cavity. This airless space between the walls becomes the thermal insulation layer that keeps liquids hot for hours – and those double-walled flasks work the same way to keep cold drinks cold. 

We have found that bigger capacity flasks retain heat for longer than lower capacity flasks. However, bigger flasks are often bulky and heavy.

In A Hurry? Here Are Our Top Picks…

Thermos Stainless King 68 Ounce Vacuum Insulated Beverage...
  • Thermos vacuum insulation technology for maximum temperature retention, hot or cold; keeps liquids...
  • Durable stainless steel interior and exterior
  • Cool to the touch with hot liquids, sweat proof with cold

The 68-ounce vacuum insulated flask was made for family use. It is built with stainless steel to last. It has added accessories to create an experience out of something as simple as drinking a hot or cold beverage.

This Thermos uses vacuum insulation technology, which involves a pocket between the two stainless steel walls. The vacuum pocket prevents temperature change in your beverage for a period of time.

If you are planning on a family camping trip, take this 2-liter Stainless King along with you. The steel construction and walls will keep hot beverages at the same temperature for a full 24 hours. This means it is safe to prepare your coffee beforehand and keep it with you overnight. It will still be drinkable in the morning.

The serving cup is attached to the Thermos flask as an extra lid. When you open both lids, there is a twist and pour stopper. A tight seal prevents liquid from leaking when assembled correctly. The carrying handle can be utilized to hang the insulated bottle from a backpack.

Key Features

  • Uses the trademark Thermos vacuum insulation technology for 24 hours of temperature retention
  • Double-wall of stainless steel
  • Exterior of bottle stays cool with hot beverages and sweat-free when cold beverages
  • Twist and pour stopper for effortless pouring without taking out the stopper
  • Comfortable carrying handle
  • Safe to wash on the top rack of the dishwasher
  • Product dimensions of 4.5 x 5 x 14.5 inches
  • Weights 1 pound when empty
  • Capacity is 2 liters

What We Like

  • The cup that screws onto the top provides an additional layer of insulation and is a nice way to drink the beverage 
  • The pouring nozzle works well without splashes. Twist it all the way, then aim it into your cup
  • If you choose to clean it by hand, it is straightforward using a bottle brush
  • It has the capacity to hold the entire pot of coffee or soup. It is perfect for sharing

What We Don’t

  • The paint has been reported to chip within a month of purchase by some users
  • This insulated beverage bottle is quite big. Most buyers are surprised by the size when they open the package
  • The handle on some flasks have been reported loose 

To fully take advantage of the insulation capability of the Stainless King, preheat or pre-chill the flask just before use. You can do this by filling the bottle with either hot or cold water and keep it for a few minutes.

When you are ready to use it, empty the flask and fill it with the hot or cold drink. 

Thermos Stainless King 16 Ounce Travel Mug with Handle,...
  • Thermos vacuum insulation technology for maximum temperature retention, hot or cold, keeps liquids...
  • Durable stainless steel interior and exterior
  • Cool to the touch with hot liquids, sweat proof with cold

The Thermos 16-ounce Cranberry Mug is a much more compact option for transporting hot food, drinks, or cold refreshments. The mug provides maximum temperature retention using the 

Thermos vacuum insulation technology.

As with other Thermoses, the Cranberry Mug features Thermos vacuum installation between two steel walls to prevent the process of convection through which heat is lost. No matter how hot the liquid inside is, it will stay cool to the touch – and ice or cold drinks will not form wetness on the side of the bottle. 

This mug holds enough for one person to drink. It is also small enough to comfortably carry to outdoor activities.

Key Features

  • Made of long-lasting stainless steel material, both inside and outside
  • Heat and sweat-proof surface
  • Built-in tea hook
  • Fits into vehicle cup holders
  • Twist and pour stopper
  • Recommended to hand wash only
  • Compatible with single K-cup coffee maker
  • This mug is unisex
  • One-year warranty
  • Product dimensions of 3.9 x 3.3 x 7.6 inches
  • Holding capacity of 16 ounces

What We Like 

  • Twist and pour stopper lets you pour your drink without making a mess
  • 100% stainless steel makes this travel mug last as long as you want it
  • Keeps liquids hot or cold for 24 hours
  • It is highly portable, making it a perfect choice for travel mug
  • The tea hook is a lifesaver for tea lovers 

What We Don’t 

  • After 24 hours, the contents of the mug will be unpalatable
  • Cleaned by hand washing only – harsher detergents of the dishwasher affect the appearance of the mug
  • Residual food and liquid can get trapped between the mug components in the lid, gasket, or the bottom of the mug

Thermos Stainless King 16 Ounce Travel Mug is loved by people who move around a lot. If you leave the house in a rush or prefer your home-made beverages, the experience just got better.

Thermos Stainless King 40 Ounce Beverage Bottle, Stainless...
  • THERMOS vacuum insulation technology for maximum temperature retention, hot or cold; keeps liquids...
  • Durable stainless steel interior and exterior
  • Cool to the touch with hot liquids, sweat-proof with cold

The Thermos 40 Ounce is another bottle for friends or family to share around a picnic table or a campfire. Like all the Stainless King Thermos products, it is made of twin steel walls separated by vacuum insulation.

This bottle is able to maintain the temperature of your drinks with a minimum fluctuation for 24 hours. It will keep the beverages fresh overnight.

The external lid of this mug doubles as a serving cup. Twist and pour stopper seals the drink to minimize spillage during transportation and serving. The integrated carrying handle is for hanging the insulated bottle from your backpack if you are hiking.

Key Features

  • Thermos vacuum insulation technology
  • Superior double stainless steel internal and external walls
  • Twist and pour stopper
  • Handle with buckle connectors 
  • The exterior of the flask stays cool and perspiration free
  • Product dimensions of 3.7 x 4.3 x 12.3 inches
  • Safe in the top rack of the dishwasher 
  • The stainless steel serving cup it comes with is insulated
  • Silver color
  • 40-ounce capacity

What We Like

  • It will fill 8 to 10 cups of coffee
  • The beverage bottle is superbly engineered
  • Hot beverages kept in this flask will stay fresh and hot overnight
  • The stopper on this flask only has to be slightly open to pour coffee

What we Don’t

  • It would be nice if the mouth was large enough for ice cubes to pass through

Care and use for the stainless steel insulated bottle 

This is another bottle for communal use, only it is smaller and lighter. The engineering work that went to making the 40-ounce beverage bottle is elegant. It is rare to find Thermos bottles that retain heat without leaving a peculiar taste on the beverage. 

Zojirushi Stainless Steel Mug, 16oz, Smoky Blue
  • Stainless steel vacuum insulation keeps beverages hot or cold for hours
  • Durable and sanitary 18/8 stainless steel interior
  • Slicksteel finish. Made of BPA-free plastic

Zojirushi Corporation has spent over 100 years of its life making products that make eating and drinking easier. It was founded in 1918 where they were producing hand-blown vacuum bottles. Their production line has since expanded to the production of stainless steel bottles and other kitchenware.

The Zojirushi stainless steel mug will keep your drinks heated or cooled for 6 hours. It has a slender design that fits into automobile cup holders. 

The lid opens with a flip. It is a tight fit to retain the heat of the bottle contents. The safety lock on the lid prevents unintentional opening.  

The inside of the mug is made of stainless steel with a SlickSteel finish.

Zojirushi uses the electro-polishing technique to provide a smooth and shiny look for the interior finishing. The result of this process is a sterile and non-corrosive surface to keep the beverages.

Key Features

  • Elegant design
  • Stainless steel vacuum insulation
  • Sanitary stainless steel interior with the SlickSteel finishing
  • The interior is stain and corrosion-resistant
  • Lid flips open
  • Safety lock on flip lid to prevent accidental opening
  • Tightly fitting flipper lid has better heat retention
  • Product dimensions of 2.8 x 2.8 x 9.1 inches
  • Weight of 9 ounces
  • A warranty period of 5 years on the thermal insulation
  • Hand washable

What We Like

  • The svelte and compact design takes little storage space
  • The temperature remains constant for at least 6 hours
  • This is an elegant mug with a well-thought-out design
  • Easy to clean
  • Nozzle for drinking eliminates spillages 
  • The lock system is innovative

What We Don’t

  • Some purchasers reported that the drinking nozzles was too small for them
  • The exterior paints chip

Zojirushi stainless steel mug is an innovative alternative to the usual travel mugs options we are presented with. This easy-to wash stain-resistant flask may be what you need to travel with.

Thermos Stainless King 47 Ounce Vacuum Insulated Food Jar...
  • Includes two inner containers
  • Durable stainless-steel interior and exterior
  • Cool to the touch with hot liquids, sweat proof with cold

This is the largest Stainless King food jar by Thermos, with a capacity of 47 oz. Inside this large food tin are two food containers. They are microwaveable, BPA-free, and dishwasher safe. 

The food jar comes with a collapsible handle and a twist-off lid. The lid can be used as a bowl. This food jar has a wide opening so it is easy to place food inside it. The wide mouth also makes it extremely easy to hand wash.

Key Features

  • Uses Thermos vacuum heat retention technology
  • Double-wall stainless steel inside and outside
  • Twin 20-ounce microwaveable and dishwasher safe containers
  • Twist off lid
  • Wide mouth 
  • Collapsible handle for carrying
  • Product dimensions of 6 x 6 x 10 inches
  • Weight of 2 pounds
  • Safe for the top rack of a dishwasher
  • Exterior stays cool and sweat-free with hot and cold contents
  • 5-year warranty
  • Made out the stainless steel

What We Like

  • This product is excellent at insulating food
  • The dual compartments inside encourage eating a balanced meal
  • The wide mouth makes filling it easier
  • Big volume of the food jar will allow you to carry enough food

What We Didn’t

  • The food containers will disfigure when the food is too hot

The Stainless King 47 ounces is the best-designed food jar we have come across on the market. It is thoughtfully designed to store food hot or cold enough until it is ready to be taken out for consumption.


To conclude this review, here is a summary of the factors you should look for in a thermos.

  • A good temperature retention score 
  • Leak-proof lids
  • A wide mouth
  • Twist and pour features
  • Integrated cap
  • They should be durable 

Thermoses have proven to be worthy companions for a trip or outdoor adventure. You should pack them alongside other essential camping gear. There is nothing better than coming to the end of a long hike and settling down to a cold beverage and a hot meal from your backpack.

We hope you choose the right Thermos according to your needs. Thermoses are all excellent products, so your choice should be focused on the capacity and price that works for you. 

Fortunately, this buying guide has compared your different Thermos options side by side to make it easier to arrive at your decision. Happy shopping!

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