It's a warning that seems a little unnecessary. The "Caution: Contents Hot" label found on most disposable drink cups and lids logically shouldn't be there. Of course, you ordered this hot drink, so you wouldn't be surprised if it was hot.
The reason why coffee cups state this comes from the Liebeck v. McDonald's Restaurants trial of 1994. One accidental coffee spill ended up granting Stella Liebeck almost $3 million dollars. It's easy to think, "All that over hot coffee?" Let's get the facts of the case straight and note how this particular court case changed disposable beverage cups forever.
A Scalding Issue
In 1992, Stella Liebeck, then 79 years old, was in the passenger seat of her grandson's car parked in a McDonald's parking lot. The two had gotten breakfast, and Liebeck's grandson parked so that she could add cream to her coffee. She held the foam cup between her knees and it spilled into her lap. Liebeck sustained third degree burns and required skin grafts on her thighs and groin.
She filed a claim with McDonald's for $20,000 to settle her medical bills. When McDonald's countered with an $800 offer, she decided to go to court.
Stella Liebeck's legal team argued that McDonald's coffee was being held and sold at too high of a temperature. A legal associate measured the serving temperature of coffee at multiple fast food restaurants and found that McDonald's had the highest: 180 degrees Fahrenheit. For reference, 150 degree water can definitely burn you within seconds, and the ideal coffee drinking temperature is between 120 and 140 degrees.
During the trial, it was also revealed that Liebeck wasn't alone. More than 700 people, including children, had been burned by McDonald's coffee in the decade before Liebeck's accident—and McDonald's knew about it.
The Aftermath
In 1994, the court awarded Stella Liebeck $200,000 in damage compensation (which was later reduced to $160,000, as the judge found Liebeck 20% at fault for her injuries). But this was what caught the media's attention: the jury also gave Liebeck $2.7 million dollars, which was equal to two days' profit for McDonald's in coffee sales. One month after the trial ended, the presiding judge reduced Liebeck's total compensation from $2.9 million to $640,000.
Even though her award was reduced, people remembered that $2.9 million dollar figure. Stella Liebeck's case prompted food and beverage corporations to be more cautious when serving hot beverages in the future.
Preventative Measures
One of McDonald's faults during the trial was that their consumers were not adequately informed of the burn risk that came with their coffee. Nowadays, we are aware. After this case, the use of cardboard cup sleeves became more widespread. Hot drink technology evolved, granting us sculpted lids with a raised opening for sipping.
Liebeck v. McDonald's Restaurants even affected the automotive industry. If the car Liebeck had been in had had cup holders, her injury could have been avoided. Even though cup holders have been in cars since the 1950s, not all models had them, and Liebeck's incident proved that they are necessary.
So, the "Caution: Contents Hot" warning has the same function as cardboard sleeves and smart drink lids. They exist to prevent you from hurting yourself with hot liquids, and in turn that protects coffee-serving companies by letting you know your liability. "Caution: Contents Hot" warnings are there to protect you, but they also reduce the chance that a case like Liebeck's could happen again.
My fellow coffee connoisseurs, now you know why your cup reminds you that it's pretty hot. Drink responsibly.