Meet Martin Riese, possessor of one of the finest palates on the planet. Someone who can spot a volcanic frizzante at 50 paces. A man to whom the question “Still or sparkling?” is a travesty.

Why should we trust him? Because Michelin-starred restaurants do. Because billionaires fly him around the planet to taste their tap water. Because he knows an awful lot about sediment.

What does he do? He tastes water. All sorts of water. Water from volcanoes. Water from glaciers. Water from space. Then he spits it out. Especially when it’s from space.

Doesn’t all water taste the same? How dare you? Wash your mouth out. Unless you’re in New York, of course, in which case, never go near the water. It tastes, Riese says, “disgusting”.

Surely water is just water? You may as well ask an artist whether light is just light. Riese is to water as J.M.W. Turner was to the sun: he sees infinite variation where others just see bright and dark. Or in this case, fizzy and tap. He explicitly says “water is not just water.”

How would he describe water, then? It’s the stuff of life. A fantasia of flavour. It is the world in a glass. Riese’s water menus (yes, there are such things) offer everything from water “harvested from icebergs freshly carved off glaciers in the remote fjords” of Norway, to 600m-year-old prehistoric water from Australia. It is also, on occasion, a trifle pricey. A bottle of that glacier water will set you back $150.

He’s not a tap-water man then? On the contrary. To shun tap water is, Riese thinks, a snobbism. He himself drinks a lot of “the tap”. Unless he’s in New York of course. Or California. Or Majorca. And he didn’t much like it in Barcelona, either. Copenhagen, however, apparently has “incredible” tap water. As a general rule of thumb, Riese says, northern taps taste better.

What about space taps? The water drunk on the International Space Station gains its flavour less from passing through aquifers than from passing through astronauts. It is, in other words, recycled urine, lightly seasoned with a dash of shower water and sweat. Then disinfected. It smells, says Riese, “really weird. Almost sweet.” But tastes, once again, “disgusting”.

Does he do birthdays, weddings, bar mitzvahs? Absolutely. Riese can design you a water menu for any celebration. Though not baptisms. Or rather, not for the water in the font. “Baptism water is nothing other than regular water. There is nothing special to it,” he says. Luther himself might have agreed.

What not to say: Pass the space water please!

Most likely to: Last longest in a drought.■