Picnic Flasks

The Thermos Flask is quite simply a picnic staple and a must have for any dining out experience whether it be picnics, camping or even at festivals.

Our Best Thermos Flask and Vacuum Flasks can keep your food and drink hot or cold.  Moreover these days you’re not limited to just drinks or soup these days either – there are some fantastic picnic food flasks on the market too. These are also great for popping in your lunch bag filled with lovely home-cooked food (or leftovers!).

Our various Vacuum flasks are also great for road trips – whether you need a quick cuppa as a pick-me-up or want to keep water or juice cool on a long summer journey.

There’s a huge range of Thermos Flasks on the market, from individual sized models to ones big enough to keep soup toasty for the whole family.  In addition there are flasks to suit every budget. I have included a few of the budget Thermos Flasks, but only ones that I feel work very well. 

If I’m honest I feel that investing a little bit more in a flask (and a good water bottle and I recommend the hydro bottle) is a very worthwhile investment. It will keep your food warmer for longer and last you for years – as I can testify to with my good old Stanley flask which has been my picnic companion since before Emily was born!

Here are some of our absolute favourites below, from old favourites like Stanley and Thermos to their more modern competitors

Best Large Thermos Flasks

Best Food Flasks

Best Individual Vacumn Flasks

I recommend these Picnic Thermos Flasks and Food Flasks as the UK’s best based on the following criteria:

  • Heat retention – how long are they going to keep my food or coffee at the right temperature?
  • Build quality – will it stand up to being dropped or having the odd knock? Is there any leakage?
  • Durability – how long will it last? Is it weatherproof or will it rust? 
  • Cost – how much value am I getting for my money?

Have you used any of these Thermos Flasks? Then please leave your review in the comments box below. Is your favourite Vacuum Flask is not on the list? Be sure to let me know in the comments below so I can review it.

Buyers guide to the best Thermos Flasks


Firstly – think about how many people you’re going to be using the flask for. If you’re taking italong on a family picnic by all means go for a super-sized version, but if you just want to take a hot drink along to work in your lunch bag than an individual flask is a much more sensible option!

If you don’t want to take a cup along with you look for an individual-sized flask with a lid that doubles as a cup or mug! Also think about things like the material your flask is made of and make sure it’s not going to be too difficult to hold (particularly in winter in case you have gloves on) there’s nothing more frustrating than dropping a flask full of the hot drink you’ve been looking forward too – trust me I’ve been there!

Traditional flasks also can keep soup warm, but you might be better looking at a food flask here – they often come with a built in/attached spoon and bowl to make eating on the go more convenient! It’s probably a better option too if (like me) you like your soup chunky.

Build Quality

The build quality of a flask or thermos is important, as skimping here will mean that it’s unlikely to be as effective at retaining heat. You also want to make sure that it’s double-walled and thick enough that you’re not going to burn your hands picking it up when it’s full!

Make sure the screw top and lid (if applicable) is well fitting and that there’s no chance of leaking – it shouldn’t require a massive effort to line the lid up and close it properly.

Does it look like it will survive a knock or a drop? It happens, and you don’t want the insulating qualities to be affected here.


Is the flask made from a durable enough material? Will it survive being carried in your backpack or picnic basket, or banging up against food containers in your lunch tote, without damage to the exterior or coating?

Think about where you’ll be using your flask too. If you’re a keen anyweather hiker for example, you’d be best going for something sturdy and weatherproof over the prettiest design! And make sure it’s made from materials that are resistant to rust, like stainless steel and aluminium.


Take my word for it – investing in a quality flask from a reputable brand, and spending that little bit worth it is well worth it. The adage ‘Buy Cheap, Pay Dear’ holds here – if you go for a super-budget version you’ll be wishing you hadn’t when you open your flask to lukewarm coffee at lunchtime! Or when your tomato soup leaks all over your bag…

Think about the PPU – price per use! If you’re using your flask every single day for lunch then it works out as really good value if you spend even £30-£35 on it. And think about how much you’ll save on takeaway coffee…

Even if you don’t use your flask every day, statistically a flask is one of the most heavily used pieces of picnicware! As well as picnics we commonly take a flask along on long drives, walks, hikes and lots more. 

Frequently Asked Questions

Most frequent questions and answers

How do Thermos Flasks work?

The sealed stopper stops heat getting in creating a vacuum that stops conduction, and the metal lining between the outer case and the inner chamber stops heat radiating.

This means there’s virtually no way heat can escape from a vacuum or thermos flask and a hot drink stored inside should stay steaming hot for several hours.

How do I clean a Thermos Flask ?

I’ve found that the best way to clean a Thermos Flask is to use washing up liquid and warm water, then rinse thoroughly with hot water (getting to your location just to taste soap is no fun trust me!).  If you want to wash your Vacuum Flask in a dishwasher check whether your flask is suitable before you begin. To remove difficult stains, Thermos recommend trying a teaspoon of bicarbonate of soda and I can safely say that it works an absolute treat on tea and coffee stains!

How long do Thermos Flasks stay Hot?

Top quality Thermos flasks can retain heat for around 24 hours. Everyday flasks should retain heat for around 12 hours. For cheaper models it is usually around 6 hours. 

How do I use my flask for the First Time?

Firstly, wash it as above and rinse thoroughly!

Then I’d suggest warming your thermos by filling it with boiling water. Put the lid on and let  it sit for a few minutes then pour out the water.

Once it’s warm, quickly add steaming hot food (at or above 74°C or 165°F) or boiling hot drinks and screw the lid on tightly.

More Essential Picnic Items

Quickly before we go into recommending picnic seating here are quick links to our other picnic essentials on the site.  If you have all these you are sure of the perfect picnic!

Can you think of another essential picnic items I need to include? If so drop me a line in the comments.