I’m posted before about how wonderful McDonald’s Premium Roast coffee tastes. I’ve also expressed how that seems to go against everything that’s right in the universe. I mean, really good coffee? From McDonald’s??!?!?!. But alas, it’s true.
That being said, while they may understand how to brew good coffee, they apparently haven’t figured out physics. Or perhaps they haven’t figured out Styrofoam. Let me explain.
In the photo above, you’ll see that McDonald’s has taken a regular Styrofoam cup, and covered it with paper. Perhaps so no one realizes they are still using Styrofoam, since it’s so environmentally taboo? Who knows. Anyway, you’ll see the mysterious coffee that happens to be under the paper. Anyone who drinks McDonald’s coffee very often has had a cup drip from the bottom. It’s very frustrating because you don’t expect a drip from the bottom, and since it’s dripping from underneath the paper sheath — there is no way to stop the drip. It stains your pants, your shirt, your desk, your paperwork, etc.
How does the coffee get there you might ask? Well, the answer is physics. Look at the following photo:
What starts as a small imperfection in the top of the Styrofoam cup, turns into a physics dynamo, which pumps coffee directly from under the lid onto your pants. If the paper weren’t there, you’d get an occasional drip, which your thumb would catch, at which point you’d simply adjust the lid so it no longer leaks. Thanks to the paper coating, however, the drip is quietly and sinisterly absorbed into the paper. It then wicks all the way down the cup, and begins randomly dripping from around the entire bottom of the cup.
The first few months of this were maddening. I thought I just kept getting leaky cups. It turns out it was much more complex. So my only suggestion to fellow McDonald’s coffee drinkers? Drink fast. Wicking is relatively slow. And the most frustrating part? Throw the cup away after you’re finished. I tended to use my McDonald’s cup all day, to save on disposables. If you keep using the flawed design, the dripping gets worse and worse.
So there you have it, your lunchtime physics lesson.