A Nice Hot Cup of Coffee…To Cool You Down?

Two years ago, the biggest thing I looked forward to about summer (besides the beach) was iced coffee. I live in a metropolitan area where there are bodegas, food trucks and, yes, Starbucks on every corner (as well as the gazillion other coffee shops trying to be or not to be Starbucks). This means that perfect iced coffee on a sweltering day is always right at my fingertips. My particular favorite in those youthful days gone by was coffee cart iced coffee. Whatever instant, bought-in-bulk, low-cost coffee they bought paired perfectly with just the right amount of milk and the crystallized sugar that sweetened the drink even though it never actually fully dissolved. (You’re always left with a half-inch of soggy sugar at the bottom of your drink). I would wake up craving the stuff. That wasn’t just the caffeine addiction, either, that was a yearning for that specific blend of flavors and the perfectly soothing coolness.

Then I noticed the people who, on a 90-degree day, were walking away with the paper cups that were designated for hot coffee. I was stunned. Sweat rolled down my forehead and into my eyes; I blinked it away and kept blinking in sheer confusion. Why on earth would anyone want to be anywhere near hot coffee on a day like that?

It turns out, they’re probably not crazy. Scientists have studied the effects of hot vs. cold coffee on hot vs. cold days and come to some interesting conclusions. When it’s hot outside, or wherever you are hot, your body has a natural strategy for cooling you down, aka sweating. Your body produces this liquid and the process by which it evaporates creates a cooling sensation on the skin. Of course, your instinct (or at least mine) is to find all of the not-hot things and put them inside of me. Water, ice cream, iced coffee; anything to make me feel like I’m not actually melting into the sidewalk.

The thing is, apparently, when hot coffee (or any hot liquid) hits your stomach, your body gets a signal that you are hot and need to cool down. Therefore, if you drink hot liquid on a hot day, when your body is already performing its cooling duties, you’re going to send a doubled cooling command. Your body will sweat more. Twice the cooling!

That being said, drinking hot coffee on hot days is not the perfect solution for cooling your body. Sweat only cools us down if it evaporates. If there is too much of it, or the air is too humid, and it doesn’t go through the evaporation process, it doesn’t cool you down all that much. That’s because it’s just rolling off of you onto the ground. So, if it’s really, really hot, or even really, really humid, a hot drink wouldn’t have the same cooling effect as when it’s just really hot or really humid. The advice that comes out of this is drink what you want and if it doesn’t work, try the other thing.

I’m still stuck on those people I saw drinking hot coffee. It was definitely a really, really hot and humid day. Like I said, the sweat was rolling down my face. My sweat was already refusing to do its actual job; adding a nearly boiling beverage to that would be exactly the opposite of what I wanted to do. My only conclusion is that those people worked in offices or stores that like to keep the inside temperature on an arctic level in an effort to combat the air-like-lava outside.
I’ve also seen people drinking iced coffee in winter. And by “I’ve seen people” I mean I drink iced coffee in the winter. There doesn’t seem to be a scientific excuse for this unintuitive behavior. I just really like iced coffee. I like drinks that I can chug and I have to sip my hot coffee until it cools off enough for me to do that, so I might as well get it on ice. I also know some people who simply can’t stand hot drinks no matter what the weather’s doing. They’re the ones who’ll go and settle in Antarctica and start a coffee shop that only serves cold brews. “Unlimited Ice!” the sign on the window would say.

The moral: drink what you like, drink what you think works for you, and don’t be afraid to experiment. You never know, something different that’s right under your nose could work even better for you and become your new favorite.