top of page

A good flask can be your friend for a long time – consider the following when choosing one

In the summer heat, we typically pay more attention to always having fresh water with us, but proper fluid consumption is also essential in cold weather. Our immune system, our skin – dehydrated from the cold weather and heating – and our body as a whole will be all the better for having the recommended approx. 2 litres of water daily intake. Having a good flask can be a great help in this; one we can take anywhere and fill up with fresh water. We can find tap water everywhere we go, so if a Floewater water filter is available in a gym, a restaurant or perhaps at our workplace, we can fill our flask with fresh, filtered water.

But how should we select the right flask and why should we not be satisfied with using an empty PET bottle?

PET is not a solution even if used several times

We often see people using an empty mineral water bottle instead of a flask, strictly in the spirit of recycling and saving money. However, this is a bad solution for several reasons.

If we have one, we must have bought it earlier, right? But if we want to do good for the Earth we should completely avoid consuming soft drinks and mineral waters from plastic bottles altogether. PET bottles pose one of the most worrying problems to our planet, which already struggles with severe environmental issues. A significant part of the disposable plastic waste already engulfing everything comes from disposable mineral water and soft drink bottles. Therefore, no one should buy any, even if they plan to use it later.

Manufacturers do not recommend refilling PET bottles either, as harmful substances may stick to their inner surface after opening them, not to mention that carcinogens may dissolve into their content due to the combined effect of heat and acid (e.g. if a refreshing, lemon-flavoured water is filled into it).

Assess your needs

We should buy a flask that we can easily take with us. We should avoid buying one which we would rather leave at home after the third day, because we find it too heavy, fragile or hard to wash. We should carefully assess our carrying capacity, the type of bag we use and where we can fill the flask up. How well can we take care of it?

If we sit at a desk all day, it is okay to have a flask that is heavy or requires both hands to open, while being on the move often suggests to choose a lighter version.

If we need one for sports, the optimal choice is the Floewater Tritane sports flask. It is made from tritane, it is free from any BPA, impact resistant and light, and it comes with a convenient and safe sports mouthpiece.

What material should we choose?

We all know that design, colour and shape all matter, but first we should find out about the materials available.


Glass is the most reliable option in terms of hygiene. No harmful substances dissolve from it, and with a properly wide mouthpiece it is quite easy to wash. However, it is not only heavy but also fragile. The practical Floewater glass flask, which is made from borosilicate glass, a material stronger than classic glass, is a good solution. This material is more resistant to changes in temperature and chemical corrosion, thus you can store hot or cold drinks in it.


Metal flasks are durable and light, which is why so many people prefer them over glass and plastic flasks. According to research, however, harmful substances may dissolve from the aluminium into the water: bisphenols (BpA, BpS and BpF) are hormone damaging substances, which may be released from aluminium in larger quantities compared to polycarbonate bottles. Stainless steel is a somewhat better solution, but if we fill it with not only pure water but also acidic and alkaline liquids, some metals may still dissolve in it.


Most flasks are made of plastic, but we should check their composition before opting for a nice colourful one. A number can be found in a triangle on the bottom of the flasks which informs us about the specific plastic they are made of.

Numbers 3 and 6 indicate plastics that are potential sources of dissolving harmful substances. Especially when a high temperature, acidic liquid is filled into the flask. The bisphenol – or BPA – dissolving from such flasks is harmful, which manufacturers are also well aware of,; that is why they place the wording ‘BPA Free’ on BPA free bottles (such as the Floewater Tritane flask). Plastics under number 2, 4 and 5 are considered safe, so feel free to buy a flask with any of these on the bottom.

Design also matters

Manufacturers use a wide variety of solutions for the flask cap and opening. A sports cap can be opened with one hand, the beak design prevents children from pouring tea on themselves, while the snap-on lid is convenient to use. However, you should know that the less you can disassemble the top of the flask and the more hard-to-reach parts it has, the more likely it is to be colonised by a pathogen, even mold, which is very difficult to get rid of in the end.

Choosing the right flask is important as it will be our everyday companion that not only helps us live healthier but also saves the environment from more unnecessarily generated plastic waste.


bottom of page