Best flask for keeping drinks hot – top 5 UK products

person with hot drinks flask

You know you’re an adult when you’ve realised owning a hot flask is a better idea than hitting a chain store for coffee every morning! Of course, they also help when you want to keep hydrated during long trips or hike. Today’s flasks offer a lot of features to suit people who need something for their office, for kid’s lunches or outdoor activities. Staying warm in the winters of the UK is a challenge and some of our picks can definitely help grab a hot drink on the go. Here are our top 5 best picks for the best flasks to keep drinks hot available in the UK online.

Our selection of the best hot drinks flask thermos available in the UK market in 2019!

1. Thermos ThermoCafé Stainless Steel Flask

2. Thermos Stainless King Flask, Midnight Blue

3. Stanley Legendary Classic Vacuum Bottle

4. Thermos Ultimate Series Flask

5. ONEISALL 2L Flask

1 - Thermos ThermoCafé Stainless Steel Flask

Thermos ThermoCafé Stainless Steel Flask
Affordable and perfect for daily usage

Made of stainless steel, the Thermos ThermoCafe flask is a versatile flask and can store hot an cold liquids, soups and stews. This flask works as it is vacuum-insulated and has stainless steel in its interiors and exteriors. Vacuum insulation decreases the chances of temperature changes by creating a vacuum space between the steel walls.

Sometimes when cold water is poured in a flask, it can condense and leak drops of water all around the space which is messy especially if you plan to use it in an office. We found this flask to produce much less condensation than normal which gets a thumbs up from us.

The cup is wide enough to serve as a serving cup and is locked in securely to prevent leaks while carrying it. At a capacity of 1 litre, the flask weighs about 500g, which is not the heaviest.

We added hot coffee at 8 am and poured it at 10 am and found it to be scalding almost and hot at 7 pm. Meanwhile, while testing for cold water, we found the temperature to be unchanged even after 12 hours. All-in-all, this is a perfect budget pick.

2 - Thermos Stainless King Flask, Midnight Blue

Thermos Stainless King Flask, Midnight Blue
Extra wide mouth & a foldable stainless steel spoon

The interiors and exteriors of the Thermos ThermoCafé Stainless Steel Flask are made of good-quality steel. This means you won’t feel the chill or the warmth while holding the flask regardless of what is inside. 

Weighing 290g, the Thermos flask measures 7 x 7 x 25cm which is perfect for daily use and can fit into a bag easily. It also comes with a stainless steel serving cup. Usage is simple and all you need to do is twist the stopper and pour.

3 - Stanley Legendary Classic Vacuum Bottle

Stanley Legendary Classic Vacuum Bottle
Unbeatable Quality

The manufacturer, Stanley has been in the business of flasks for over 100 years now. It’s been amongst the most trusted for a long time and most of our parents/grandparents have grown up using it. The flask is built like a ‘battleship’ and it certainly looks that way with its hammertone green finish and thick insulated walls. They use food-grade stainless steel and is 100% BPA & phthalate-free, so you will not find a metallic taste or smell while using.

The quality really stood out for us and the flask stood up to all sorts of tumbles, falls and rough handling. This is why think its perfect for camping, hikes and other outdoor activities.

While Stanley claims that it can keep liquids hot or cold for 24 hours, we found this claim partially true as no brand can maintain temperature perfectly. So we added boiling water to it and found the water warm even after 24 hours- hot enough to make tea with. It performed even better with cold water.

This Stanley flask can hold 1 litre which is good enough for 1-2 people in the outdoors for a day but if you’re a big group, consider buying more than 2. It comes with a lifetime warranty which is simply the best in the industry!

4 - Thermos Ultimate Series Flask

Thermos Ultimate Series Flask
Great design with an insulation shoulder bag with extra storage

With a subtle charcoal colour and unique features, the Thermos Ultimate Series Flask, Charcoal does a good job of thermal retention for up to 24 hours. The body of the flask is made of a lightweight plastic while the interiors are made of stainless steel. It has silicone rings on the base which protects the flask and keeps the flask upright on a variety of surfaces. The Thermos Ultimate Series Flask weighs just 380gm when empty thanks to the lack of metal in its construction.

Another unique feature is a two-part stopper. The inner stopper allows the liquid to be poured without allowing much cold air from affecting the temperature. While the outer stopper can be unscrewed fully to allow heavier liquids like soups, chunky smoothies etc.

The lid of the flask is also usable as a cup and is covered in sticky rubber. Although a minute feature that you wouldn’t think about, this helps the cup retain friction on smooth surfaces.  The flares around it also keep it secure on rocky surfaces making this flask great for use in your hikes, treks, picnics, basically anywhere outdoors.

5 - ONEISALL 2L Flask

Unique Pouring Mechanism For No Spills

This One Is All flask comes with a handy strap so that you can carry it easily on your outdoor activities, hikes, trails and more. The body of the flask is made of a baking finish shell and a stainless steel cup and the vacuum insulation layer is responsible for the heat retention.  With a capacity of 2 litres and 5-layer insulation, this ONEISALL flask has one of the highest capacities on this list.

It has a unique pouring mechanism and all you need to do is press on the red button at the top of the lid. Once done, press the button again to restore to its original position. Like most other good flasks, this flask also comes with a lid that can be used as a cup of capacity 300ml. This inner lid with good seal function and can keep the water keep more hot and cold.

What to look for when buying a hot drinks flask?

Now that we’ve discussed the top 5 flasks that keep drinks hot, here is a deep dive into the characteristics that you should keep in mind before buying one.

Heat/Cold Retention

Not all thermal flasks are created equal! Some thermal flasks can keep your drink hot for more than 24 hours, while others can average around 6 hours or less. Think about when you will be using a flask- is it on a journey or is it needed to keep your coffee warm from your home to the office? This is why it is important to check reviews before purchasing as some products are less effective real-time than they claim.


Since a flask is portable, it is essential for the lid to be secure and leak-proof. Some flasks use corks to keep the liquid inside secure but we prefer screw caps instead. Some flasks come with lids that double up as a cup which is handy if you don’t want to carry cups with you.


The heat-retention of your flask is heavily dependent on the material it is made from. Stainless steel would be ideal as it is durable, easy to clean and can retain heat very well. We would suggest that you avoid plastic or glass as they are prone to breaking and will not retain heat for long.

Also, check for the insulating provided by the flask. A double-layered flask will prevent heat from escaping your drink quickly while a vacuum-sealed flask also does the same with more efficiency.

Other Features

There are some other features unrelated to heating which will make using the flask a lot easier. For example, a carry handle makes it easy to carry your hot flask without hurting your hand. If you are buying your flask online it is pretty hard to tell how well the flask is going to hold up even if you read all of the customer reviews. 


See also:

Our selection of the best hot food flasks in the market to keep your soup hot

Leave a Reply

Your email address will not be published. Required fields are marked *