What water you shouldn’t drink in summer?

As summer progresses, the amount of water consumed increases and the risk of filling your body with damaged (“burnt”) water increases.

“Burnt” water is water that has been stored in a PET bottle and overheated in the sun for a long time. It is not advisable to drink such overheated water even when it has cooled down. Also, water in glass bottles does not “like” the sun – it becomes more oxidative. To avoid such a risk, water should be stored properly and everyone should be able to distinguish by taste whether the water is “burnt”.

Traveling a lot in warm countries, I have noticed that 70% of the water in PET bottles sold in small street shops, which are in the sun all day long, has burned.

What are the signs that the water is no longer desirable to drink?

Squeeze the water bottle and smell the air that comes out of it. If the smell and taste has a slight alcohol or lemon aroma, the water will be spoiled.

More careful water users recognize this taste and smell, but do not always interpret it as a “burnt water” taste. I have noticed that many of my colleagues – Water Sommeliers – do not recognize this special smell and taste. Not because they don’t feel it, but because they’ve never paid much attention to it before.


Quite recently, I came to the idea that the taste of this (“burnt” water) should be calibrated not only by water taste specialists, but by everyone.

What does flavor calibration mean? In order for the Water Sommelier to be able to recognize the taste of different minerals in water, each mineral is first calibrated separately. That is, each mineral or its compound is tasted by diluting it in distilled (pure) water. In this way, we learn to recognize the tastes of individual minerals.

It would also be valuable to calibrate and learn to recognize the taste of “burnt” water for everyone. Especially for the new generation that started to drink water from PET bottles from early childhood. 

If you feel the call that you would like to widen your sensual intelligence by learning the taste of water, register here BECOME A WATER SOMMELIER and we will inform you about the next Water Sommelier course in Riga.  In meantime you can warm up and learn some basics online at www.waterambassador.org 

How to calibrate the taste of “burnt” water?

Buy still and carbonated water, deliberately keep them in a very warm environment for at least a day, so that the water in the bottle heats up like tea. Then cool both bottles to room temperature.


Next – “tasting”.

The taste reference point requires the same water bottles, but not overheated. First, squeeze both the overheated and non-overheated bottles and smell the contents. Then drink from one bottle and the other. Remember this taste, this will be the calibration of the taste of “burnt” water.

I recommend doing this with carbonated and non-carbonated water, as it is very likely that it will be more difficult for non-carbonated water to feel these nuances of taste. Before the “tasting” it is advisable not to eat or drink anything for at least 30 minutes. It is best to do it in the first half of the day, from nine to eleven o’clock, when the perception of flavors is at its highest. 

When performing this taste calibration, invite work colleagues in the office, or family members at home. I believe that everyone should learn to recognize the taste of “burnt” water.

I recommend using the water drinking reminder PickAqua, which regularly reminds not only to drink, but additionally motivates the user to drink water with various interesting facts about water at each reminder.

Go for smaller sips, but more often!

PickAqua drink reminder calculates at the same time the mineral amount you consume from the water.

What you shouldn’t do in summer?

Do not keep water bottles in the car cabin. It is much safer to put them in the trunk. There are at least three reasons for doing so.

  • Water will not spoil.
  • In direct sunlight, water becomes more oxidative, which means that water moves us away from sustainable health. This also applies to water in glass bottles.
  • The magnifying glass effect. Rarely, but it happens that a bottle filled with water can create a magnifying glass effect, as a result of which the car interior can catch fire.

If you are at the beach, be sure not to keep the water in the open sun on the hot sand. If you are with children, ask them to dig a water hide. Children will definitely enjoy the process itself. The water will be kept cool and safe to drink. 


What exactly happens when plastic heats up where water or food is stored?

The hotter, the more plastic materials can end up in water and food.

Most plastic packaging for drinks or food products emits very small amounts of chemicals. Heat helps break down the chemical bonds in plastics like plastic bottles, and these chemicals can migrate into the water.

According to the US Food and Veterinary Service, the amount of the chemical is too small to cause health problems. But scientists who study these effects over the long term, point out that all these small doses can add up significantly if we neglect plastic packaging, especially in the summer. Heat in PET bottles accelerates the release of antimony and acetaldehyde. Antimony is used in the production of plastics and can be toxic in large doses.

The rate of antimony leaching from PET bottles is low when the storage temperature is up to 25°C. However, at temperatures above 45°C and higher, release of antimony can occur very quickly.

In summer, the temperature inside the car can exceed 70 degrees. In the experiments, it took 38 days for bottles of water heated to this temperature in the laboratory to show antimony levels above the safe level.

After all, the trace amounts of chemicals that a person can consume from plastic food or beverage containers left in the heat will not pose a short-term health hazard. But more attention should be paid to how many different plastic products are in our everyday environment. For example, synthetic clothes.

Water in petrol stations

When thinking about the water storage temperature, the environment in which the PET bottles are located should also be taken into account.

I have noticed a relatively careless attitude in gas stations, when water bottles are placed right next to the fuel pump for the convenience of customers. The PET material is breathable, meaning that the evaporating fuel penetrates the water bottles.

Of course, how long the bottle has been near the fuel filler also matters here. In order to feel the taste of fuel in the water, it would have to stand next to the fuel filler for at least a couple of days.

The good news is that the turnover of water packages on hot days is high and most likely the bottles will not be at the gas station for too long. In Latvia, it actually only happens during the summer period, but even then it shouldn’t be like that. It’s just not “Feng Shui”. 

On most bottles is clearly and brightly written – “do not store near volatile substances and strong smells”.

Bottled water should be stored under the same conditions as consumers store other food products.

To learn more about water drinking habits, as well as to discover the interpretations of the composition of all mineral waters available in the World, download the PickAqua water choice app.

In the water choice app PickAqua, you can find all waters by its dominant element or various other value parameters.

Dan Volevah

Water Sommelier

Instagram: @volevah


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