This is the first post in a series of several. There are many misconceptions and misunderstandings about our beloved drink that need to be exposed. This inaugural installment deals with roast level and caffeine content.
It is commonly believed by coffee drinkers that darker roasted coffees contain more caffeine than lighter roasted coffees. I am not entirely sure where this myth came from, but I imagine it has something to do with the taste of dark roasts. Darker coffee can indeed have a “stronger” flavor (i.e., bolder, smokier, more bitter) than its lighter counterpart, but this has next to nothing to do with its caffeine content.
It should be rather obvious than a green coffee bean (well, actually, coffee seed, but more on that in another post) can be roasted many different ways. The vast majority of coffee in American highways and byways is somewhere close to a “medium” roast. Most fast or semi-fast food restaurants and gas stations have been serving a similar type of coffee for decades–something resembling Folger’s or Maxwell House. When Starbucks began its meteoric rise to a household name, it also helped to proliferate the idea that “gourmet coffee” was more defined by its roast level than by its bean quality. Starbucks differentiated itself from “everyday” coffee by its dark roasted flavor, which was the easiest (and quickest) way to make an immediate statement to customers. Devotees of Starbucks soon began to define cup quality by its boldness—a darker coffee was thought to be a “better” coffee—and boldness meant more caffeine content.
But this is flat-out false. There are two major coffee varieties: arabica and robusta. Arabica is typically the higher quality variety and robusta is the higher caffeine variety (generally about twice the caffeine content of arabica). Most restaurant and gas station coffees are a mix of robusta and arabica, while most specialty coffee shops are serving straight arabica. This fact alone gives the higher caffeine nod to the former and the better taste nod to the latter.
Roast level has little to do with caffeine content, although some argue that darker roasts actually have less caffeine due to the chemical reactions that take place at the higher heat levels and longer roast times. So if you are simply looking for a larger dose of caffeine, you are wasting time and money standing in line at the snooty speciality shop in your town; the gas station is where you should really be. (Of course, if taste is important to you at all, then this “caffeine jolt” may be more pain than joy.)