Light or Dark Roast coffee - What's the Difference?
Short Answer - it depends. Long Answer - it depends on if you’re talking about the taste or caffeine content. What we think of as a simple beverage is in reality, a very complex one.
It all starts with the seed of the fruit of the coffee arabica plant. These very hard, very dense seeds are referred to as green beans in the coffee industry. Coffees grown in different regions have different character profiles due to climate, altitude, and terrior that affect their final taste.
These beans are then roasted. Here at Signature, we lovingly roast these beans in small 24-pound batches in a cast iron drum over infrared burners. Our roastmasters are true artisans as they play with time, temperature, and airflow to coax out the best flavors of each coffee. The longer the beans spend in the roaster and the higher the temperature, the darker the beans become. As moisture is removed from the beans, they puff up, lose weight, and get darker. A longer roasting time will also bring the oils to the surface, creating a glistening shine to the dark roast.
So, that’s the how and why of the different shades of roasted coffee. But there’s more to it than just the color…
WHICH ONE HAS MORE CAFFEINE?
Okay, most of us drink coffee for that caffeine rush. That’s what start’s our day and get’s us goin’ or keeps us going during that afternoon slump. Caffeine stimulates our brain activity and releases neurotransmitters that make us feel more alert. But will a darker roast give us more caffeine than a lighter roast? Well, that depends on if you’re comparing them by weight, by volume, or by varietal.
The caffeine content changes little during the roasting process. The beans would need to be roasted at levels far beyond what is normal to make a significant difference. So, if there is such a minuscule difference between light and dark roasts - why is there such a perceived difference? Some people assume the darker the roast, the higher the caffeine content. Not true. Others believe that the caffeine is "burned off" as the beans get darker, so lighter roasts would have more caffeine. Also not true. Well, maybe a little bit true If the coffee is measured by weight and not volume, then the difference is still negligible.
However, when comparing caffeine levels by volume the results are skewed because of the difference in density. When beans are roasted longer, they lose weight, puff up, and become larger and lighter. So, if you’re measuring by volume, you’ll have less actual coffee in the darker roasts, so therefore less caffeine.
Other factors that can affect the caffeine levels include the type of beans and the way they are brewed. Robusta coffee, a less expensive harsher-tasting varietal, very rarely found in specialty coffee, contains almost twice the caffeine than the Arabica varietal. As to the difference in caffeine by brewing method - it just depends on how much coffee you use.
Something to think about - can your state of mind affect the "perceived" caffeine level of your cup of coffee?
WHICH ONE TASTES THE BEST?
There is no right answer here, so let’s just discuss the differences. A big part of the flavor equation is where the beans were grown, the climate, the terroir, and how the beans were processed after harvesting. However, the most pronounced flavor is determined by how light or dark the beans are roasted.
Lighter roasts create a denser coffee bean with bright fruit-forward, herbal flavors. Lighter roasts are more complex, reflecting more of the distinct origin flavors and the unique elements of the bean. Lighter roasts also have a much thinner body and mouthfeel than darker roasts. They have a more delicate but complex flavor profile. Think bright, crisp, fruity, floral, herbal, acidic. Think white wines.
Dark roast coffee beans are roasted for a longer time or at a higher temperature. These beans will lose more moisture, making them less dense with a more single-note flavor as the complexities of the beans start to disappear. As the beans spend more time in the roaster, they develop oils that are brought to the surface which creates more viscosity, or body in the cup, making it feel thicker in your mouth. Dark roast coffees are full-bodied with deep, bolder, and more straightforward flavors. Think bold, robust, smoky, toasty, nutty, and chocolatey. Think red wines.
If you don’t already have a favorite just try both and compare. Just know that for an honest comparison, you’ll need to keep everything else the same -brewing method, coffee-to-water ratio, etc.
BOTTOM LINE
Lighter roasted coffees have a complex, light and bright flavor profile with a thinner body. Darker roasted coffees have lots of body with a bold and robust flavor profile. Whatever your preference, both contain plenty of caffeine, healthy nutrients and wonderful taste. If you’re wondering which roast is the best option, remember that it boils down to personal preference!
And if you’re like a lot of us, we want it all. We want the complexity of the lighter roasts and the bold nutty taste of the darker roasts. Medium roasts can give us all that and more. Medium roasts are popular with most people because of their balanced notes that aren’t too overpowering.
Drink what you like, and like what you drink...