We recently wrote about how the only real reason to use a water filter is to keep your water cold. But why do we like our water to be ice-cold in the first place?
One of the biggest reasons has to do with taste — specifically, the lack of it. Cold temperatures slightly suppress the sensitivity of our taste buds, meaning we can taste fewer flavors when the food or drink we’re wolfing down is cold. Cold suppresses our sense of sweetness, too: That’s why sodas are always served over ice, as drinking them lukewarm makes them excruciatingly sweet. Try letting a glass of soda warm up to room temperature — it’ll taste sweeter and more acidic (the cold affects your perception of tartness, too) than cold soda.
It’s also possible that cold water may be an “acquired” taste, a preference that we as a species have developed over many years. That’s because most of us associate warm water with stagnant, uncovered water (e.g., a puddle or pond water). And since stagnant water can be dangerous to drink — it provides a better incubator than running water for many kinds of bacteria and parasites — we consider flowing water to be more palatable.
Finally, a lot of it is purely psychological. According to science writer Luis Villazon, “A 1997 study at the Yale School of Medicine found that the action of drinking is more thirst quenching than being rehydrated through a nasogastric tube.” In other words, the same amount of fluid can be pumped into two different people, but the one who drinks it out of a glass will feel more hydrated.
The study explains that this is due to the fact that the physical sensation of drinking tells our brains that we’re rehydrating. Since the sensation is enhanced if the temperature of the drink is hotter or colder than your mouth and throat, a cold glass of water is more satisfying than a lukewarm one.
In short, there’s nothing really wrong with tepid water besides the fact you’re used to having it cold. Unless it really is from a puddle, in which case, yeah, you might want to reconsider drinking that.