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Zojirushi Thermos Review

Zojirushi Thermos is one of the best vacuum sealed container on the market. It can keep your hot drink hot and cold drink cold. How it does this is with a technology that is over a hundred year old. The double wall interior prevents heat from transferring, keeping the temperature stable. What most people dont know is that most manufacturer uses this same technology in their thermos. However, is there a difference between the manufacturers? This review will take a closer look at Zojirushi thermos and we will see how it works and whether its any good.

Zojirushi Thermos Review Quick Summary

Categories
Zojirushi Thermos Stainless Steel Mug
PerformanceExcellent
Capacity17 oz. / 0.5 liter Other Model Varies
ColorsStainless Steel 18/8
Temperature CapabilityHeat Retention* 169°F @ 6 hrs. / 118°F @ 24 hrs.
Cold Retention** 46°F @ 6 hrs.
Warranty5 Year
Brand AwarenessWorld Famous
Country of ManufacturerThailand
ThoughtsZojirushi Thermos is the one of the best around. If you want to keep you drink at a stable temperature, this is the way to go. The only bad thing is all the gasket and cleaning. If you do not clean it thoroughly, mold will form. But that is the price to pay for performance.
Reviewed ThermosZojirushi SV-GWE50 Stainless Steel Mug


History of Zojirushi

Zojirushi was started in 1918 under the name Ichikawa Brothers Trading Company. They specialized in vacuum insulation which was a breakthrough technology at its time. In the early 1920’s they started to produce vacuum bottle and utilized the famous elephant trademark. Throughout the years, their product expanded and eventually changed their name to Zojirushi in 1961. Today, they produce a wide range of products from rice cooker, to bento box. But what they are most known for is their commitment to quality. Even though their product commands a premium, consumers are willing to pay for its durability and performance.

Zojirushi Thermos Design

The basis construction of any thermal stable bottle is its vacuum sealed wall. However, every manufacturer have their own personal touch when it comes to manufacturing a thermos. This section will discuss the various components that goes into Zojirushi Thermos.

Vacuum Insulation

The Vacuum insulation concept was developed in 1892 by James Dewar, a cryogenic scientist. He wanted a way to keep hydrogen cool so that it wouldn’t evaporate. To do this, he used two wall of glass and vacuumed the air between it. Hence the invention of Vacuum insulation.

Today implementation is much like the original design. Air is sucked out between two walls to provide a thermal barrier. Some bottles uses a glass wall to do this others a stainless steel wall. Zojirushi use to make their insulation with glass until 1981. When they created their Tuffboy line, they switched to stainless steel. Overall, this design is better as they are unlikely to shatter like glass will.

How Vacuum Insulation Works

How a insulation work is by preventing heat from being transferred. Thermal energy needs a conductor to travel from one area to another. One of the most common medium is air. If you removed that air, it remains trap in a container. To further this effect, manufacturers will often line the inner outer wall with Copper or Aluminum. This sheet of Copper or Aluminum will reflect the heat back towards the container. With the heat being trapped, the only way for it to escape is via the lid. You can minimize the loss by applying gasket and keeping tightly sealed.

Different Pouring Mouth

There are many different moth on Zojirushi models. Some just have a simple Wide Mouth. Other have a design where you can drink straight from the bottle. However, the model that I recommend you get is the one where you can pour into a cup. The SV-GWE50 has an easy open design where you can just open it with a button. The lid acts as a cup so that you do not have to drink from the bottle.

Smelly Drink?

One of the quickest way to ruin a drink is by drinking straight from the mug. Our mouths, me and you is filled with bacteria. For a quick stint, it should be fine. However, if you plan on going for a few day backpacking. It is always better to pour out the liquid then drink it. Backwash occurs when you drink from the bottle and eventually culture of bacteria is formed. This is why your bottle of water stink sometimes if you leave it for a day or two. Besides, this design lets you share and cool your drink as necessary.

For this of you who would still like to drink from the bottle, you still can. The wide mouth is still there and the pouring mechanism is removable.

Zojirushi Thermos Parts and Gasket

The little parts and gaskets are what makes Zojirushi Thermos perform so well. They are also one of the worst part of it. While it provides excellent sealing, it is also very cumbersome to clean. Things like milk and coffee will get trap in there and you will smell it for days. If you get lazy about cleaning, it will start to develop mold…a sign of bacteria infestation. Little nooks and cranny also tend to develop mark and getting at it is quite difficult. So while it is a better design on Zojirushi part, it is also one of the worse.

These gaskets also have a separate issue. Overtime, it will dry and crack. To get your bottle working at optimal performance, you would have to replace it. Unfortunately, it is quite expensive if you factor in shipping. Usually, its better to just replace the whole bottle. The good thing is that you can actually buy parts unlike other manufacturers.

Country of Manufacturer

In the past, most of Zojirushi products where made in Japan. Recently, some their products are now being made in China and Thailand. While they maintain that the quality is the same. I would still prefer products that are made in Japan. They also charge a bit of a premium for products made in Japan. Most likely due to the cost in Manufacturing. While it is a trade off, what you choose to buy is up to you. Just expect to pay more for stuff made in Japan.

Zojirushi Thermos Thoughts

Overall, the performance on Zojirushi Thermos is amazing. While their rating will vary by the bottle. I find that they often time under rate what it can hold. If only the gasket weren’t so difficult to clean, this bottle would be one of the best. However, if you want superior performance and durability, this is the only way to go.


I hope you like this Zojirushi Thermos article, If you would like to see more, please visit our Kitchen Gadgets page.

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