Have you ordered a mocha lately? Do you realize that "mocha" shouldn't actually mean "chocolate-flavored-coffee," and instead should mean really, really expensive coffee? And that someday, it could mean the best decaffeinated coffee in the world?

For me, mocha always meant a combination of chocolate and coffee. That's what most of the world thinks of when they order a mocha at a coffee house. It wasn't always so. No one knows exactly where the idea to call the combination "mocha" came from, but we know what probably inspired the name: excellent marketing.

Mocha beans were once the most sought-after beans in the world. This particular strain of coffee beans, now known as Coffea arabica, is still grown in the hills of Yemen. In the 1700s, it was shipped out through the now-unused port of Mocha, otherwise known as Al Mokha. Only the richest people could afford them. At one point they were exclusively consumed by French royalty. Even as production went up and price went down, they remained expensive and sought-after.

Arabica beans are now cultivated elsewhere, but the ones from Yemen supposedly still taste best. Like grapes, they are supposed to pick up flavors from the soil, and those flavors can't be replicated elsewhere.

There is a new twist on the mocha story. In 2004, a strain of Arabica beans in Ethiopia was found to have far, far less caffeine than other types of coffee. Decaffeinating beans saps their flavor, so the existence of a naturally-decaffeinated strain caused a lot of excitement. Coffee beans have a chemical called theobromine (also found in chocolate). When a methyl group (CH₃) gets added to the molecule, it becomes caffeine. The process is called methylation. It looks like, in this bean, the process is blocked. Scientist are trying to induce the same quality in other strains. So one day, "mocha" could come to mean high-quality decaffeinated coffee.