London - It’s a mystery that puzzles thirsty sleepyheads all over the world – why does the glass of water on your bedside table change taste overnight?
Well, puzzle no longer – the cause has been revealed by the science website Discovery News.
Its experts say the water turns more acidic during the night. While it cannot technically go off, these subtle chemical changes affect the taste.
Although water does not contain the proteins or sugars that would enable microbes to break it down like they do with food, its chemical composition does change.
This is because as it is left open to the air overnight in the glass, it absorbs some carbon dioxide from the atmosphere. This creates an extremely diluted and harmless solution of carbonic acid.
As for bottled water, it should in theory stay pure forever as long as it is stored in a cool, dark place.
Daily Mail