Water does have a flavour and it’s sour, find scientists

Research says it should be considered the sixth taste

Sarah Young
Tuesday 06 June 2017 15:24 BST
Water does have a taste after all
Water does have a taste after all (Getty/iStockphoto)

Water doesn’t taste like anything, right?

Wrong, because scientists have discovered that H20 does actually have a distinct flavour, and it’s a sour one at that.

If you had to describe water, flavoursome is unlikely to be the first word to enter your head but new research from Caltech University, California, says that it should be considered an independent flavour.

The work, which appeared in the journal Nature Neuroscience, monitored the tongues of mice while tasting water and discovered that the taste sensors which were being stimulated were in fact the sour ones.

The team also went on to suggest that this accounts for water being considered the sixth taste alongside sweet, sour, salty, bitter, umami.

Assistant professor of biology, Yuki Oka, explained that our ability to taste water isn’t just a coincidence though, and that it’s actually down to our tongue being able to sense the liquid.

"The tongue can detect various key nutrient factors, called tastants— such as sodium, sugar, and amino acids—through taste, however, how we sense water in the mouth was unknown,” Oka said.

“Many insect species are known to ‘taste’ water, so we imagined that mammals also might have a machinery in the taste system for water detection.”

To prove that the sour cells contributed to water detection, the team went on to use a technique called optogenetics that allowed them to stimulate sour cells with light instead of water.

After replacing water from the animal’s water bottle and replacing it with a blue light, they discovered that thirsty genetically engineered mice would go to the spout for water, encounter the light, and “drink” it.

Despite not being hydrated, they continued to lick the source because the light was triggering a sensory cue that water was present.

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