We get this question a lot: Do light roasts have more caffeine than dark roasts?
There’s so much misinformation out there, folks are never quite sure what’s true and what’s not. In fact, I often hear people order light roast coffee because they believe it’ll promise more of that boost. But are they right about that?
Let’s look at the science of roasting and see if this checks out—or if it’s just an urban coffee myth.
During the roasting process, we take raw (green) coffee from room temperature and modulate the flavor and profiles of the bean over 9–14 minutes. We typically crank up the temperature hotter than 400 degrees Fahrenheit while we’re at it.
Closeup of our tried and true 5kg US Roaster Corps. You'll find this guy at our Roasting Annex.
The beans’ color changes quite a bit, from green to yellow to light brown to deep brown to black. The flavors also change via maillard and Strecker reactions (really cool and complex non-enzymatic reactions that I won’t spend much time on here, but if you want to learn more, I suggest checking this TED video about chocolate chip cookieschange at different temperatures.) One thing we fail to look at (or adequately explain) is what happens to the caffeine inside of the coffee bean.
Do you know why coffee has caffeine? It’s a feature that was naturally selected over the years. We obviously know that caffeine is a stimulant. The plant uses this to defend itself from many different pests. The caffeine overstimulates the bugs, paralyzing them, and preventing them from further damaging the plant (pretty ‘effin cool defense mechanism, if you ask me!).
So, we know that caffeine is a naturally occurring stimulant. We also know that caffeine does not begin to degrade until around 455 degrees Fahrenheit (e.g., it’s stable and not breaking apart). For example, Mission Coffee’s darkest roasts are lucky to get up to 430 degrees Fahrenheit. Logic would tell us that the bean often does not get up to a high enough temperature to cause the caffeine to degrade. So, if you had a light roast bean and a dark roasted bean of the same coffee, per volume, it would likely have a comparable amount of caffeine, right?
A finished roast cooling off in the cooling tray of our 5kg US Roaster. Coffee displayed here is a light roast, as seen by intact cellulose center and light brown coloration.
Caffeine content is actually correlated to coffee varieties (each plant will have a slightly different level of the chemical). Most coffees, whether they’re light or dark roasts, actually have the same amount of caffeine.
So, what is actually dissolvable in a coffee? And does it change from a light roast to a dark roast?
Well, does burnt toast taste different than perfectly golden toast? (Yes). Can you get the same nutritional value from each? (Maybe? I’m not a scientist.) It seems likely and logical that dark roasts are slightly less soluble (there’s much less stuff to dissolve; less flavors, things have degraded and changed, etc.). But, one thing that doesn’t change at these roast levels is caffeine.
While a light roast bean and dark roast bean may have the same amount of caffeine, when you look at the finished brew, there may be negligible smidgen more caffeine in a dark roast simply because there’s less of other stuff in there.
If you want to get even deeper into this topic, I recommend checking out this article on Daily Coffee News. You’ll have all the roast-related details you need.
Turns out, there’s no real difference if you’re drinking a dark roast or light roast. You’re likely to get a nice dose of caffeine from both. But, if you want to have a drink with slightly less caffeine, look for coffee beverages with a lower CONCENTRATION of coffee to water. (There’s a lot more coffee per ounce in espresso than cold brew; more in cold brew than drip).
Next time you’re standing in line at Mission Coffee Co., know that, light or dark roast, you’ll get that much-needed caffeine boost either way!