There's a scientific reason for why coffee shoots out of the lid

By Shannon Sweeney — / Death Wish Coffee Blog

Why does coffee shoot out
of the lid of your cup? 

Picture this: You're on your way out the door when you realize you don't have any coffee left at home. So what do you do? Stop at your local coffee shop to grab something on the way to work. When you're walking, not paying attention to your stride, coffee shoots out of the lid. White shirt: Ruined. Skin: Burned. 

Walking with a travel cup or a disposable coffee cup should be considered a sport because of this exact reason. If you can get from Point A to Point B without dripping, you deserve an award. After all, every last drop of this precious potion we call coffee gives us the power to get through our day

But why does this happen in the first place? Science says it's because of the shape of your lid. Yes, scientists actually researched this. 

"It happens because of the sloshing of coffee against the lid, which is kind of unique. A the end of the lid, the hole is right up above that. As the coffee sloshes against the end of the lid, that velocity is amplified and it splashes up through the actual hole," Rob Kaczmarek, marketing director at Convergent Science, told BBC.

Coffee lids with bigger openings are less likely to spill. If the sides were more angled or rounded, this may not happen, according to research. In fact, more and more companies are designing new lids for cups to avoid coffee shooting out of the lid — this is the coffee of the future, people. 

Other factors that affect this are how full the cup is, as well as the speed you're walking — a 2012 study found that most coffee spills between the seventh and 10th step of a journey. Count your steps carefully, and slow down — no one should be in that much of a rush to get to work, anyways. 

The easiest solution? Sit and enjoy your coffee. That's what Italy does

Related: 6 of the best (and worst!) coffee inventions



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