Coffee heightens our senses while beer dampens them. And yet anyone who’s ever handled either beverage knows that coffee is far more precarious in its cup than a freshly poured beer. It turns out there’s a scientific explanation as to why, despite being a little tipsy, you’re less likely to slosh your beer than your coffee.

It all comes down to foam.

Scientists at Princeton University looked at three drinks: coffee, a lightly foamed beer and a heavily foamed beer. What they discovered is that though foam isn’t ideal for drinking, it’s very helpful in protecting against spillage.

According to, “Just as solid foam reduces noise by absorbing sound waves, liquid foam does the same for motion…The more foam that was present, they observed, the more energy was absorbed and the less sloshing occurred.”

Therefore, the debate over which style of beer tastes best may rage on, but the debate over which beer is least likely to splash is pretty clear-cut. Foamy beers like Guinness are more stable in the glass than lighter beers like Heineken.

As for coffee, maybe we’ve finally learned why cappuccino has become so popular. Not only is that layer of foam tasty, it also helps in preventing you from sloshing it all over your shirt.