What is Caffeine?
Caffeine is a naturally occurring stimulant found in coffee, which is enjoyed by millions of people worldwide for its energizing effects, increasing alertness and attentional performance. While coffee is known for its caffeine content, the amount of caffeine in your cup can vary depending on several factors. Is the roast level one of them? Well, yes and no.
Does Dark Roasted Coffee Have More Caffeine?
Dark roasts are assumed to have more caffeine mainly due to their bold, bitter taste and darker colour. However you can't taste caffeine in coffee, and the colour of coffee after it's roasted does not indicate the amount of caffeine either. So is this a myth?
Caffeine and Roasting
During roasting, many chemical reactions take place, browning the beans, and creating hundreds of new aroma and taste compounds. Most of the water content in the green coffee bean escapes as steam, and the finished roasted coffee bean is now brittle and pourous enough to grind and brew as coffee.
Caffeine is a stable compound at typical roasting temperatures, so levels are virtually unchanged by roasting. Therefore roasting lighter or darker does not change the amount of caffeine in coffee. BUT, the way you measure your coffee for brewing might impact the caffeine content.
Brewing By Weight
Using the same coffee (species and variety), a lighter roast will produce denser, smaller beans due to there being slightly more water content left in the bean. A darker roast of the same bean will have less water content, and each bean will be lighter, and larger.
So if you weigh out 20g of coffee for pour over / filter brewing, you will have less light roast beans than you will dark roast, because they are more dense. And if the caffeine content is the same per bean, then you will have more caffeine in the dark roast, only due to the fact that you have more beans in 20g of coffee.
Brewing By Volume
Alternatively, if you measure using a scoop, you will get the opposite effect. Darker roasts create larger beans, so you will get less beans (and less caffeine) per scoop. For a lighter roast, you will fit more of the smaller beans in a scoop and therefore get more caffeine.
- Per bean, there is very little difference between light and dark roasts when it comes to caffeine
- The colour or flavour of your coffee is not a good indication of caffeine level
- If you measure your coffee by weight, darker roasts WILL contain slightly more caffeine than lighter roasts
- If you measure your coffee by volume/scoop, lighter roasts WILL contain slightly more caffeine than darker roasts
- We recommend using a scale, so that you can accurately measure your brew ratio for a consistently great cup!
So there you have it, dark roast coffee does not contain more caffeine than light roast coffee, but if you are brewing by weight (recommended), then you will get very slightly more caffeine in your cup using a darker roast, as you will be using more beans.
How you brew your coffee also makes a difference to the amount of caffeine in your drink. Read more here: Which Coffee Drink Has The Most Caffeine?