I Just Learned What Happens To Diet Coke On Planes, And It's Fascinating

<span class="copyright">AerialPerspective Images via Getty Images</span>
AerialPerspective Images via Getty Images

HuffPost UK has previously learned that some parts of the plane are frankly too filthy to touch.

And it turns out that flight attendants aren’t just being friendly when they greet you onto the plane, either ― they’re actually quietly sussing you out.

And now, we’ve discovered another behind-the-scenes flying fact; Diet Coke is among the most complicated drinks staff have to pour mid-air. In fact, all fizzy drinks behave strangely due to the pressure in the cabin.


The altitude causes the drink to fizz ― like, a lot.

Writing on the blog Golden Wings, flight attendant Jet said, “Soft drinks foam up a lot more when poured out of a can, and the worst culprit for this is Diet Coke – I literally have to sit and wait for the bubbles to fall before I can continue pouring.”

That’s because, as the blogger points out, “the aircraft cabin isn’t pressurised to sea level, but rather to the equivalent of about 7 or 8 thousand feet.”

That’s why some people feel dizzy on a flight and also why we’re more likely to feel drunk quicker in the air.

And because “The pressure inside the bottle [or can] is the same but because the pressure outside the bottle is lower,” fizzy drinks’ corks pop and bubbles fizz a little harder, The Real Review writes.

The blogger stresses that she doesn’t mind what customers order and is happy to pour any drink people want.

In fact, the author even devised their own method of pouring a froth-free glass of the fizzy drink on a plane.

Why is Diet Coke specifically so fizzy?

The science makes sense, but why are people saying Diet Coke is more fizzy on flights, in particular?

Well according to McGill, “Diet soda actually has a slightly higher viscosity than sugary soda, which slightly diminishes its fizzing potential. However, a slightly higher viscosity means that when bubbles do form, they’re a bit more stable.”

They added, “This explains why Diet Coke not only fizzes more than classic Coke, but the foam also lasts longer!”

By that logic, all “diet” versions of fizzy drinks ought to fizz more, but perhaps Diet Coke is more noticeable as it’s usually the most popular order, and therefore flight attendants notice it more often.

Makes sense that that’d apply mid-air too, right?

So perhaps you might want to order a can of classic Coke next time you’re on a plane ― it might save you and the flight attendant a bit of faff!