Here’s Why You Should Never Order Diet Coke on an Airplane

When you’re on an airplane, flight attendants can make the skies that much friendlier with extra cookies, a pillow swiped from first class, or a tour of the cockpit for the kids. So there’s no reason to annoy them with a drink order. A 2013 post from flight attendant blog, These Golden Wings, recently resurfaced on Delish, which may have you second guessing your in-flight drink order.

Turns out that some flight attendants hate it when you order Diet Coke. It’s not that they hate the drink per se, but they hate the way it reacts in high altitude. Apparently, Diet Coke takes longer to pour than any other soft drink or beverage while up in the air, because the high altitude and lower air pressure reacts with the C02 in the drink, to make it extremely bubbly. That means when someone orders a Diet Coke, the flight attendant has to crack open a can, pour it into a glass and wait for the bubbles to go down so they can actually fill the glass and not serve passengers a mere two sips of soda. “Pouring diet coke is one of the biggest slow downs in the bar service and on the shorter flights those precious seconds count!” wrote the These Golden Wings blogger.

While the low pressure-high altitude situation makes every drink extra bubbly, for some reason it particularly effects Diet Coke, much to the consternation of flight attendants. “If all 3 passengers ask for diet coke I’ll often get them started, take another three drink orders, serve those, and then finish the diet cokes,” wrote the blogger. When people order Diet Coke, flight attendants just have to grin and bear it—or come up with clever solutions for making it all go much faster. Their trick is pretty smart, as demonstrated in this video, using air pressure to slow the flow and prevent bubbles and overflow.