Jeff King, Roastmaster
Lamppost Coffee Roasters Mythbuster: Dark roasts have more caffeine than light roasts OR light roasts have more caffeine than dark roasts
We get questions about caffeine content all the time. Some just about how much caffeine is in coffee, and sometimes about if a dark or light roast has more caffeine. I’ll toss in a quick table to roughly answer the first question, although how much caffeine is in some of the drinks depends on how strong you make them.
A little surprise in this chart is that a shot of espresso has less caffeine than a “normal” cup of coffee. This is because the amount of caffeine extraction is related to how long the water is in contact with the coffee, and espresso is extracted in 20-30 seconds (ideally), and brewed coffee takes a few minutes. That was just an aside. On to the questions at hand…
Myth 1 – Dark coffee (or bold) has more caffeine than lighter coffee
This is derived from the fact that dark roasted coffee is more acrid or bitter, which is what caffeine actually tastes like. But, this flavor is actually caused by the carbon of the deeper roast and not by caffeine.
Myth 2 –Light coffee (or even green or white coffee) has more caffeine than dark coffee
This belief is common and can be found all over the internet. It is assumed that roasting burns off some of the caffeine. The reality is that the caffeine molecule is pretty much impervious to heat and there is a negligible loss of caffeine in the bean during the roasting process.
A coffee bean has nearly the same amount of caffeine in its green state as after it is roasted, to any drinkable level. If coffee is measured by volume before brewing, lighter roasts can have more caffeine as beans get larger during roasting. If coffee is measured by weight, the darker roasted beans weigh a little less than the lighter beans, so the dark roast could have more caffeine.
So, enjoy your coffee! Drink up! The roast level isn’t affecting your caffeine intake. Find the level you really like, and if you need to control your caffeine amount, consume less, or brew with less coffee, brew with a method that minimizes contact time between the water and coffee.