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Although Thermos may be a well-known generic term for flasks, it is just one of many brands. In fact, the best flasks come in various shapes and sizes, and have many names. Our suggestions below have successfully mastered the art and science of the thermos-this ingenious insulated container can complete the work of a portable kettle or refrigerator without a plug.
Whether it's a thick "food flask", a smooth "airless bottle" or something in between, the purpose of the flask is to keep food and beverages hot or cold all day long without leaking. Some of the winners on our list can be insulated for more than 24 hours, which is enough to survive the hardest hike or the hardest commute.
In this article, we have selected several flasks that are excellent in terms of insulation, leak resistance, durability and, of course, value for money. Before proceeding, please review the buying guide below for some useful tips on buying the best flask.
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The flask has come a long way, and the best vacuum flask today is a miracle of micro-engineering. These flasks are made of multiple layers of BPA-free and rust-proof stainless steel, which can withstand years of bumps and bumps, allowing you to enjoy hot tea and ice-cold drinks season after season.
They also won green points without having to buy drinks in disposable cups. If your flask is big enough for lunch, you can save money and plastic.
You can buy a flask almost for free, but considering how often you may use the flask, it is worthwhile to spend a little more for quality and durability.
When buying a thermos, you tend to get value for money. Of course, you can get flashy brand-name flasks, but if you only pursue quality, you will not spend more than 25-30 pounds. For beverage containers, this may seem a bit luxurious, but you will soon save more on beverages and lunch.
18/8 grade steel: Today's best flasks are made of stainless steel and do not secrete chemicals (in other words, they do not contain BPA) or strange smells. The best products are made of 18/8 grade steel (also known as grade 304), whose high nickel content makes it rust-proof and extremely durable. It is also non-magnetic, which may be disappointing if you wish to decorate the thermos with refrigerator magnets.
Multi-layer insulation: Double-layer insulation can form a vacuum layer, which is essential for keeping hot drinks hot and cold drinks cold. Some flasks include more layers for better insulation. The 100% stainless steel construction of today's flasks means that there is no risk of breaking the inner wall when dropped.
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Insulation cup: A good flask should also pay attention to the insulation of the detachable cup, if any. This way your drink will stay warm while you drink it. At the same time, it stays cool outside, so you don't risk your hands getting burned.
Capacity: More capacity means more content can be enjoyed. This also means carrying more weight, but only if you fill it up. For the best insulation, buy a slightly larger (but not heavier) flask than you need, and leave a few centimeters of air at the top. We have listed the capacity and weight information of all flasks below.
Price: From £23 | Buy now from Amazon
Throw it away, sink it, wash the dishes, drink it directly, or even make tea with it. This fab lightweight flask is designed to withstand under any circumstances without affecting the temperature of its contents, keeping your brewing at a comfortable temperature for 12 hours.
The two-piece locking lid doubles as a rotatable water outlet, so it is perfect for sipping while you are walking, although the plastic part of the lid does not feel as durable as metal. We also like the classic Sigg handle, which doubles as a lever, so if your hand is cold or dirty, you can open it with a stick. There is even a built-in tea strainer, so you can use loose tea leaves or whatever you find in your adventure to make tea.
Main specifications-material: 18/8 stainless steel, with polypropylene filter (can be used for dishwashers); capacity: 500ml; size: 25.5 x 6.9 x 6.9cm; weight: 381g; optional colors: 3 (silver, white, black)
Price: £27 | Buy now from Amazon
This stylish, lightweight, double-insulated bottle is made of sturdy stainless steel and is powder-coated to prevent it from slipping off sweaty hands, keeping the beverage cool in the hot sun. It does keep hot drinks hot for 12 hours, but in summer adventures, this flask really works, keeping iced drinks cold for more than 24 hours.
Hydro Flask is also available in a smaller 12-ounce version and a "wide mouth" design, but only the standard mouth fits the insulated silicone sports cap (£9.50), designed for sipping on the go.
Main specifications-material: 18/8 stainless steel (can be used for dishwashers); capacity: 600ml; size: 26.5 x 7.3 x 7.3cm; weight: 295g; available colors: 3 (more colors available from other retailers)
Price: £25 | Buy now from Amazon
Considering its size, the Thermos King is surprisingly light (it is larger than the Stanley Master, but lighter and cheaper) and looks spectacular. Intimate details include a rotating cork that allows you to pour drinks without removing it and a space-saving handle. However, its holding time is not as long as that of Master Stanley, and it drips a little when it comes out of the spout, at least when it is full.
Thermos King can be used for several years, but it is not officially dishwasher safe, and you don't even plan to immerse it in water (if you do this, you will break the manufacturer's 50-year warranty). Curious users report that it is indeed intact in the dishwasher, despite the peeling color.
The flask in the picture is cranberry red; Argos is also available in midnight blue (£27.99). Thermos offers more colors and sizes.
Main specifications-material: 18/8 stainless steel (not suitable for dishwashers); capacity: 1.2l; size: 31 x 10.5 x 9.4cm; weight: 670g; available colors: 2 (other retailers provide more colors)
Price: From £18 | Buy now from Amazon
The king is back, and this time he is full. Here, Thermos’ insulated stainless steel lid doubles as a food bowl and comes with a full-size folding stainless steel spoon. Stews and soups are hot all day, while fruits and buckets of yogurt stay cool all day-if you put an ice pack in the flask, it will be cold in the refrigerator. Ice cream won't go very far, but if you put a handful of packed lollipops from the refrigerator in a bottle, they will freeze for several hours.
The flask in the picture is midnight blue, but Argos also has a red color (as shown in the picture) and costs £18.99. Find more colors on the Thermos website.
Main specifications-material: 18/8 stainless steel (unofficial dishwasher safe); capacity: 470ml; size: 14.2 x 9.4 x 9.4cm; weight: 390g; available colors: 2 (more colors available from other retailers)
Price: £21 | Buy now from Cotswold Outdoor
This large, sturdy flask comes with a removable shoulder strap so you can carry it on your shoulders when you go up the mountain on the weekend. It’s even better if you go there with friends, because there is a second plastic "friend cup" hidden inside the larger metal cup. The flask is wide enough to be used as an insulated lunch box, but you need to bring your own spoon. The insulation is very good, keeping the contents steaming for more than 12 hours.
Main specifications-material: 18/8 stainless steel copper plated (can be used for dishwashers); capacity: 1l; size: 23 x 12 x 11.5cm; weight: 708g; available colors: 1
Buy now from Cotswold Outdoor
Price: £70 | Buy now from Amazon
A new product from the creators of the 106-year-old Stanley Classic, this smooth, sturdy flask can keep hot drinks for longer than the promised 27 hours, and iced drinks can keep for more than 100 hours (if you are found, Good luck) Frankly speaking, the heat wave lasted so long). So if you are packing a car for a camping trip, this is the flask to bring.
Master realizes its insulation magic through the "QuadVac" four-wall insulation system, which is completely made of BPA-free 18/8-grade anti-rust steel. The thermos cup is made of the same material and does an excellent job of keeping the temperature of the drink during your lunch. The stopper is plastic, but is lined with steel, so your drink will never come into contact with the plastic, and we have found that it can reliably prevent leakage.
Our only complaint is that even before it was filled, the weight of this flask was close to one kilogram and there was no smaller size.
Main specifications-material: 18/8 stainless steel, with steel-lined plastic inner cover (can be used for dishwashers); capacity: 750ml; size: 30 x 8.8 x 8.8cm; weight: 889g; available colors: 1
Price: £23 | Buy now from Amazon
If you are not a big fan of hot drinks but still want a special flask to keep your drinks cool during camping trips, long days and overnight stays, then this smooth product from travel favorite Contigo is the ideal choice. It claims to be able to refrigerate drinks for 28 hours, and in our tests, it did this. Although the temperature drops a bit when the ice starts to melt, we found that the ice-free liquid is at the same temperature as when it was first added after 28 hours. In some cases, they stayed cold for much longer than the prescribed time.
It is 100% leak-proof-no matter how hard we try, we can't let any liquid escape, and the automatic trigger means you can easily drink with one hand. Finally, there is an extra loop handle on the top, so it can be easily hung on the bag or carried in this way. All in all, it is very stylish and sturdy
Main specifications-material: stainless steel (plastic lid can be used for dishwasher) capacity: 720 ml; size: 7.6 x 7.6 x 27.4 cm; weight: 382g; available colors: 2
Price: £22 | Buy now from Amazon
At the other end of the weight range is this gorgeous new product from Thermos, weighing just over 200 grams (of course, before there is nothing in it), with a "direct drink" spout on the top, perfect for train work.
Thermos designed the flask to be as light and ergonomic as possible, and has a cool, sweat-resistant appearance. It can’t compare with the Stanley Master in terms of absolute insulation capacity (to be honest, no flask can), but it can still refrigerate cold drinks for a few days and keep hot drinks piping hot all day long.
Main specifications-material: stainless steel (unofficial dishwasher safe); capacity: 470ml; size: 22 x 6.5 x 6.5cm; weight: 210g; available colors: 1
Price: £30 | Buy now from Amazon
This vacuum flask from Black+Blum is a very unique and environmentally friendly choice that keeps your food delicious and warm. It has a capacity of 400 ml, and its leak-proof twist cap ensures that no matter where you go, food and drinks can be left in place. After sealing, it can keep food warm for up to 6 hours, while boiling water can keep it for 10 hours or more. At the same time, cold food and drinks will stay cool for about eight hours. Finally, this colorful and ergonomic spoon is fixed to the flask by inserting artificial leather straps, so you will never drink soup like tea.
Main specifications-material: 304 stainless steel, polypropylene, HIPS, silicone and artificial leather (not suitable for dishwasher/microwave oven); capacity: 400ml; size: 16 x 9 x 9cm; weight: 349g; optional colors: ocean, Orange, olive
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