When Napa-based wine master James Cluer told his client, Qatar Airways, that he would be out of contact for a month and a half, the airline asked questions. Where was he going? And why for so long? Cluer disclosed he was planning to fulfill a lifelong dream and climb Mt. Everest (29,000 feet above sea level)—a trip that had been years in the making. Qatar Airways suggested he might want to conduct a wine tasting to learn how altitude affects the palette outside of a plane cabin. Cluer agreed. Enter a few seasoned sherpas.

The story is a funny one—either the ultimate marketing gimmick, or an extreme experiment in satisfying one's curiosity. Turns out, it was the latter. Cluer and Qatar Airways both take wine seriously. The Doha-based airline has won numerous awards, including Best Airline Wine List, and all of its flight attendants are WSET certified and able to provide sommelier services. And Cluer has dedicated his life to the grape. In addition to consulting, buying, and selecting what wines to serve onboard Qatar Airways flights, he also runs 16 wine schools in the U.S. and Canada and operates a luxury wine tour business called Fine Vintage Ltd.

As one of only 300 Masters of Wine on the planet, we wanted to delve deeper into what may be the world's most extreme wine tasting and ask Cluer a few questions:

Q: Interesting idea to climb to basecamp at Mt. Everest to taste wines for in-flight offering on Qatar Airways. What was the most memorable part of the experiment for you?

A: First, the scenery was breathtaking. Of course. And I found the tastings to be very insightful, especially when it came to the sparkling wines. They were much more bubbly and effervescent—foaming out of the bottle. Of course, we brought two of each bottle in case one was corked. Or, should I say, the sherpas brought them. Those guys are incredible.

Q: Where do you normally taste wines for in-flight service—in the air, or on the ground?

A: On the ground, namely because tastings can go on for days. We do sample wines on flights, but a good tasting is a three-day process.

Q: Is there a difference in the taste of wine at 29,000 feet versus 35,000?

A: It's not so much height as it is length of the journey. Low humidity in the cabin dries nasal cavities. The longer you're in the sky, the blander your taste buds get, which is why we choose wines with big flavor profiles.

Q: What wine tastes even better at 35,000 feet?

A: I'd have to say the port we have onboard. It's a 1974 Kopke tawny port from the Douro Valley in Portugal. It's bold with lots of strength and intense aromatics. Just beautiful.

Q: What are some of your best tips for drinking wine at high altitudes? Whether in a plane or high above sea level?

A: Sip slowly, and don't go overboard. I'd say 3-4 glasses max on a 10-hour flight: a glass of champagne to relax before take-off, white wine with your starter, a red wine with dinner, and a dessert wine or port with your movie.

Q: What's your favorite wine destination?

A: It's such a cliché, but I love Napa. That's why I live here. My second favorite destination is Bordeaux, where I lived and worked for some time. Tuscany, too. There are so many it's hard to decide!

Why did James Cluer climb the mountain and drink the wine? Answer: Because they were there!

Adrien Glover is deputy digital editor at Travel + Leisure.