The One Beverage Flight Attendants Secretly Hope You Don't Order (And Why)

Flying can be a stressful ordeal. By the time you battle your way through a busy airport and take to the skies, you just want the comfort of your favorite drink. But due to factors from science to logistics, there might be a few limitations around what's ideal to order. You should never order shaken cocktails on an airplane, for example, because most flight attendants don't have the equipment or the time to make them. And there's also a particular soda that, while certainly possible to serve, flight attendants secretly hope no one will order: Diet Coke.

This is because Diet Coke is fizzier than other sodas, which means it takes flight attendants longer to pour it. They have to pour slowly and keep letting the soda's foam calm down before pouring more. Other drinks pour so much faster, they can serve multiple passengers in the time it takes to provide one Diet Coke.

Why is Diet Coke so especially effervescent? Because it's easier for bubbles to form and pop in a liquid doesn't have sugar and so isn't viscous. Plus, in order for bubbles to develop, the surface tension of a liquid has to be lower, meaning that the bonds between the molecules in that liquid can be broken — otherwise those bonds act like bubble barricades. Diet Coke has potassium benzoate and aspartame, which are considered "surfactants," or chemicals that can actually lower a liquid's surface tension. Between the lack of sugar and lower surface tension, Diet Coke can be explosively bubbly.

Thanks to science, soda can taste different on a plane. The airplane is dry, and there's a lot of pressure in the air. Both that dryness and the cabin pressure tend to dull our taste buds. Things will taste less sweet. Therefore, as long as you can have sugar, you may enjoy ordering a regular Coke more — it will seem less sweet than normal, and may be the exact flavor you want. Flight attendants will appreciate you for ordering the soda that's easier and faster to pour.

If you're set on Diet Coke, try asking for the can. If you don't, flight attendants may stick to a system of splitting cans between passengers in order to preserve supplies, which is why they pour soda into cups by default. As long as there is enough soda, most flight attendants will be happy to give you the can.

"I always give them two cans and a cup on the bar round because I don't have to pour it," says one Reddit user. If you have a full can, you also have more soda to work with — just be sure to request a cup, too. Drink half on its own, then elevate your Diet Coke with liquor or mix-ins, depending on what you have or also order from the crew. Try a splash of cranberry juice, or red wine to make a diet version of kalimotxo, the Spanish wine and cola combo.