Before going to bed, many folks fill up a glass of water to set aside at the bedside table. This saves a trip for most folks who wake up in the middle of the night feeling parched while also providing hydration first thing when the sun wakes up. However, the water you put on the bedside table at night isn’t the same when you drink it in the morning.

The water changes tastes overnight due to a change in the water’s chemical composition. The open-air exposure of the water allows it to absorb carbon dioxide and become slightly acidic, as a tiny fraction of it turns into carbonic acid. While it doesn’t make the water unsafe, it may interfere with those who are attempting a more alkaline lifestyle. For more on this scientific change, click here:: Does water ‘go off’?