As a keen walker, I know how important it is to have a good quality vacuum flask as part of my kit.
A nice hot cup of tea or coffee whilst I am out could be the difference between a great walk and…
returning home early!
Related Post: Best Thermos for Keeping Coffee Hot
In my chart below I highlight five of the best vacuum flasks for keeping liquids hot.
Before we look at those individual flasks in lots of detail, let me just highlight some of issue relating to vacuum flasks.
History
Vacuum flasks were invented by a Scot named James Dewar in 1892, which is why sometimes they are called Dewar bottles.
Made of brass, his flasks were designed to keep the temperature of chemicals constant.
In a sad twist to the story, Dewar refused to get his design patented, which he would regret 12 years later.
In 1904 two Germans realised the potential the design had for keeping drinks hot or cold and they designed and patented the Thermos flask.
They are actually two separate flasks placed inside one another and joined at the neck.
The gap between the two flasks is a vacuum which stops heat being transferred.
But before I start to look at each of these flasks individually, I will quickly list some of the features that make a vacuum flask great.
Insulation
Any flask that you are looking at must have at least a double wall vacuum insulation. Most flasks will quantify the number of number of hours that a drink can be kept hot or cold for.
Most flasks can keep drinks colder for longer periods than they can keep drinks hot.
The vacuum insulation means that no matter if your drink is piping hot or ice cold, the outer case of the flask will not burn or freeze your hand.
In this post, the flask with the longest insulation times is the Stanley Classic.
It promises to keep drinks cold or hot for a staggering 32 hours.
Stainless Steel
The next quality that you are looking for in a vacuum flask is that it is made from 18/8 stainless steel.
To keep things simple, 18 refers to the percentage of chromium that the steel is made from.
So 18 steel contains 18% chromium.
8 refers to the percentage of nickel in it, which is 8%.
The chromium makes steel rust proof.
The nickel makes it shiny and more resistant to corrosion.
18/ 8 stainless steel is food grade as it is used in most food preparation and dining contexts.
Insulated Cup
Some buyers want a vacuum flask to come with a cup, which is traditionally how they have been designed.
But as the designs and the markets have changed, fewer flasks now come with cups.
In the past people wanted to drink their coffee in a cup, whereas now people are happier to drink straight from a (well designed) flask.
Perhaps it could also be that vacuum flasks were often used in group or family outings.
In these settings, you would have wanted more than one cup.
Nowadays, flasks are used solely by individuals and so cups are not quite so necessary.
Besides, a cup makes a flask taller and heavier- which might be a disadvantage.
Leak proof
Any flask needs to be leak proof so that it does not create a mess.
If it is being carried in a bag, you need to know that it will not leak on any of the other things that you have in the bag.
You don’t want other items spoiled but also you don’t want to lose any of the drink that you have made.
Lifetime warranty
Some of the best flasks in my comparison have got a limited lifetime warranty.
This means that if they are any defects in how the product was made, you should be able to claim for a new item.
Other flasks have five year warranties.
You do need to be careful however.
Because of the rise of fake goods, some manufacturers will only honour their warranties if you buy from their Amazon shop.
Cleaning
A flask needs to be as easy as possible to clean otherwise people just might stop using them.
In an ideal world all flasks would be dishwasher safe.
But very few of them are and in my comparison only one of them is.
Most flasks just the lid is dishwasher safe as the body needs to be hand washed.
Carrying
How will you carry your flask?
Will it spend most of its time in a backpack or will you be carrying it separately?
The Stanley Classic and the Stainless King both have old fashioned handles.
The CamelBak and the Yeti can be carried with your fingers.
So, now that we have looked at some ideal features, let’s have a look at each flask in turn.
Stanley Classic Bottle
Details
- Capacity 44 oz | 1.25 L
- Hot 32 Hours Cold 32 Hours
- Dimensions 14.25″ (H) x 3.9″ (W)
- Lid Screw top
- Clean Handwash
- Cup Yes
- Warranty Lifetime
Features
This is a timeless classic, a little changed mainstay of campsites across the country.
The details speak for themselves.
Claiming to offer outstanding levels of insulation- 32 hours for hot and cold and 160 hours for iced drinks, this flask is the real deal.
And guess what?
Looking at the reviews, those claims are fairly accurate.
The Stanley classic is built to take a few knocks and it’s lifetime warranty backs up the claim.
It is BPA free and rust proof.
Using food grade 18/8 stainless steel, this bottle comes with an insulated 8 oz cup.
Yeti Rambler
Details
- Capacity 36 oz | 1 L
- Hot ? Cold ?
- Dimensions 10.75″ (H) x 3.75″ (W)
- Lid Screw top
- Clean Dishwasher
- Cup No
- Warranty 5 Years
Features
This bottle comes in seven different colors including olive green and seafoam!
Using DuraCoat these colors won’t fade, peel or crack however much the bottles are used.
Yeti do not quantify the number of hours that your drink will stay hot and cold for which is a bit of a stupid omission in my opinion.
This bottle uses double wall vacuum insulation which promises to keep drinks ice cold or piping hot “until the last sip”.
However, the reviews are impressive and they back up the claim that drinks will be keep cold or hot all day long.
Using kitchen grade 18/8 stainless steel, all parts of this bottle can be happily put in the dishwasher.
The cap is designed so that the bottle can be carried with three fingers, looped through the cap.
Whilst it doesn’t come with an insulated cup, the bottle uses “over- the- nose” technology so that the bottle can be drunk from directly or can poured easily into a cup.
The yeti comes with a 5 year warranty but it is designed to be “virtually indestructible”.
CamelBak Chute
Details
- Capacity 40 oz | 1.1 L
- Hot 6 Hours Cold 24 Hours
- Dimensions 11″ (H) x 3.8″ (W)
- Lid Screw top
- Clean Handwash
- Cup No
- Warranty Lifetime
Features
CamelBak are most famous for their hydration packs- small rucksacks with drink pouches and a tube attached.
But the Chute is a thermos bottle which promises to keep drinks hot for 6 hours and cold for 24 courtesy of its vacuum seal technology.
It comes in 9 different powder coated color choices, including Fig and Violet and a limited lifetime warranty.
Using 18/8 grade stainless steel and BPA free plastic, in order to keep your CamelBak bottle pristine, make sure that you hand wash it. The lid can be placed in the top rack of the dishwasher.
This model doesn’t include an insulated cup but it has a rapid hydration, angled spout built into the lid.
The Chute doesn’t have a handle but the lid includes a hook so that you can carry it with one finger.
Thermos Stainless King
Details
- Capacity 40 oz | 1.1 L
- Hot 24 Hours Cold 24 Hours
- Dimensions 12.1″ (H) x 3.7″ (W)
- Lid Screw top
- Clean Handwash
- Cup Yes
- Warranty 5 Years
Features
The Thermos Stainless King comes from another insulated bottle giant.
A company that is respected so highly that the brand name describes a whole range of products.
The 40 oz. Stainless King only comes in one color which is Cranberry.
This thermos flask is built using 18/ 8 grade stainless steel and using its famous vacuum insulation, it will keep drinks cold for 24 hours and hot for 24 hours.
Insulation- wise, that places it second only to the the Stanley Classic.
Also, like the Stanley flask, this Thermos model comes with an insulated cup.
Another similarity is that both models have a handle on the side.
Its impressive 5 year warranty helps to make the Stainless King a very popular thermos flask.
Corkcicle Triple Insulated
Details
- Capacity 25 oz | 0.7 L
- Hot 12 Hours Cold 25 Hours
- Dimensions 7″ (H) x 4″ (W)
- Lid Screw top
- Clean Handwash
- Cup No
- Warranty 1 Year
Features
And now for something completely different.
In so many different ways…
Most other vacuum flasks (and all of the ones in my comparison) make a lot of their “double insulated” properties.
Well, the Corkcicle goes above and beyond with its triple insulated system which allow it to keep drinks cold for 25 hours and hot for 12 hours.
And unique because of its gorgeous design.
Forget your powder coated colors, the Corkcicle is available in up to 26 different colors, including copper.
Also this model isn’t a plain cylindrical shape- it has a “corrugated” design which helps make the bottle easier to hold.
Most other thermos flasks appeal to campers, hikers or people who work outdoors by how their flasks perform.
The Corkcicle is a solid but luxury product that wants to be bought by people who care about how their flask looks more than how it performs…
Intrigued? Find out more here.
