It has all happened to us all. Let’s go to bed with a glass of water to quench thirst just before sleep. But the next day, when we take a sip from the same glass, we realize that the taste of water is different. But why?
Science has the answer. It is something chemical. And it is that in that glass of water there are not only H2O molecules. There is all a variety of different ions and molecules also, that they can change over time and thus affect the taste of the water. One of them is carbon dioxideThat is, what we exhale during respiration, which causes Coca-Cola to have bubbles and that polygamous gas responsible for acidification in the oceans AND also in the glasses of water.
The water iscapable of dissolving numerous substances of different physical state (liquids, solids and even gases), until it reaches equilibrium with the atmosphere. So when the glass of water we take to bed has been in our room for a while, gradually absorbing carbon dioxide from the air. H2O and carbon dioxide molecules react with each other to form carbonic acid, causing the pH of the water to decrease, and thus making it slightly more acidic. Hence, it acquires a stranger flavor when drinking from the same glass in the morning.
Chlorine and temperature: key elements of the taste of water
We could say that the gas molecules that are mixed with those of the liquid element are responsible for the unpleasant taste of the water, also when they stop interacting. In fact, in water treatment centers are often added to this small amounts of other components, for example chlorine, in order to purify it, since chlorine has been shown to be quite effective in killing bacteria or viruses that they could be floating in the water. That’s why chlorine is added to swimming pools. And that’s why accidentally swallowing water while swimming in one, the feeling is so annoying.
But then, why a fresh glass of cold water tastes good? The answer is simple.
When you are used to drinking tap water, with a little chlorine, tends to associate it with clean, fresh water, while by allowing the chlorine to dissipate as a gas over time, the glass could lose that characteristic refreshing touch.
That is, aside from chemical factors, the main reason for a worse taste of water is most obvious: temperature. As a general rule, low temperatures remove flavor, while water at warmer temperatures it has greater mobility between its particles, which enhances the flavors that the taste buds can detect. As with wine, we are unable to appreciate the subtler flavor notes of the water.
In any case, drink from a glass of water that we have left out all night it won’t hurt us, you can only leave us a little bad taste in your mouth.