Which Coffee is Stronger: Light or Dark Roast?

by Peter Taylor | Last Updated: 16 February 2020

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Which Coffee is Stronger: Light or Dark Roast?

When you wake up in the morning or go for your afternoon pick-me-up, have you thought about why you choose the roast of coffee that you choose? Perhaps you go for the dark roast because you believe, as so many do, that the darker the roast, the stronger the coffee and so it will be better for giving you the jolt you crave. Light roast coffee, in the perception of many, is seen as being not only lighter in color, but also in flavor and in caffeine content; thus, it’s not as strong, so it often gets passed over. But is this assumption actually correct?

If you’ve been figuring that dark equals stronger, you’re probably wrong! The only thing that dark roast coffee is stronger in is oil level. This is because the longer roasting time that produces the dark color of these beans forces the oils out, giving them a reflective sheen. In every other way though, light roast coffee is actually stronger than dark roast. What gives?

How Light Roast Coffee is Made

The answer lies in the making of light roast coffee versus medium and dark. When coffee beans are roasted, they are done for different periods of time in order to create the light, medium and dark roasts. Light roasted coffee isn’t exposed to heat for very long, medium in between, and dark roast has been exposed the longest. Lightly roasted coffee is actually roasted in order to preserve the character of the bean rather than to just roast it until it goes dark. This also means that light roast coffee has now become the favored bean for connoisseurs in particular as it’s much easier to taste the different types of beans and get a variety of flavor profiles.

Still though, there will always be lovers of the dark roast, so let’s break this down.

Light Roast vs Dark Roast: Caffeine Content

The big question for people when it comes to light and dark is caffeine content. For a long time, it was assumed that the stronger taste of dark roast coffee (strong to the point of too bitter…) meant that it also had a lot more caffeine content. This is where the idea of a ‘strong cup of black coffee’ came from and why it was so popular.

However, the roasting process of roasting the beans until they have at least one crack to it and nearly a second one (thus releasing more of the oils), has the effect of slightly reducing the amount of caffeine in the bean. Now, this is slightly, as in, the amount is less when you’re looking at pounds of coffee, not by the cup. By the cup, there’s no difference in caffeine content between light, dark or otherwise. The difference in caffeine actually comes from the species of beans with Robusta beans having double the caffeine of Arabica (but at the price of a much harsher flavor). So if you’re looking for a caffeine jolt, pick the coffee you like and don’t worry about light, dark, or medium roasts.

Light Roast vs Dark Roast: Taste

Dark roast was once considered to be for the people who had the strong palate and could ‘handle’ the coffee. However, darkly roasted coffee loses a lot of its original flavor profile and can instead taste burnt, too bitter, or has a bolder flavor (which may or may not be a good thing, depending on your preference). Quality dark roast can have notes of chocolate to it and it will be more bitter than light roast. A quality dark roast will also be smoother and less acidic. Dark roast therefore is more popular with people who have a sensitive stomach to acids since there’s a lot less in it compared to light roast.

Which Coffee is Stronger: Light or Dark Roast?

Light roast coffee on the other hand tends to be sweeter than dark roast. It’s also roasted so briefly that the original flavor of the coffee bean is left intact, so it will likely have a fruitier flavor (coffee beans are fruit after all!) Depending on the origin of the bean, there will be other notes to the profile, and they are very wide ranging nowadays. Roasters also don’t have to hide the flavor of the beans because the beans themselves are better quality. This gives manufacturers more room to try out different combinations, leading to a lot more diversity. The same goes for dark roasts, but with light roasts, it’s much more noticeable. On the negative side, light roasts are a lot more acidic and can cause discomfort in sensitive drinkers.

Light Roast vs Dark Roast: Smell

There are few smells that are as distinctive as coffee. Some people who don’t even drink the stuff still like the smell! Is there a difference between light roast and dark roast smell?

Light roast beans do have a richer and stronger aroma than dark roast because they haven’t been burned or roasted too heavily. Dark roast on the other hand has a smokier and more carbon smell and if the beans were roasted for too long, there won’t be much of a smell at all. As to which smells better, that’s really between you and your nose!

Light Roast vs Dark Roast: Oils

One of the big differences between light roast and dark roast is the amount of time they spend being roasted and that matters because of the amount of oils that are released. In the case of light roast coffee, no oils are released and thus you get the more acidic and flavorful profile. In the case of dark roast, you get more release of oils, leading to a smokier odor and a more bitter, but smoother drink (as we saw earlier).

Dark roast coffee beans and light roast coffee beans look different because of the release of these oils. Light roast beans are light brown or tan in color whereas dark roast beans are dark brown or black and have a sheen to them. They will also brew differently, with makers of super automatic espresso machines in particular, recommending that you be careful when using very oily beans as they can clog up your machine over time!

What About Super Dark Roast Coffee?

Most of the coffee you get will likely fall between light, medium and dark roast, but there are some coffee that are really black. These include French roast, Italian Roast, continental roast, expresso Roast and New Orleans. People drink these super dark coffees under the assumption that they are stronger. However, for many people, they are far too roasted to get any flavor aside from burnt. The beans are so roasted that they are black or nearly black in color and have a lot of oil on their surface. The flavor of these coffees actually depends more on the roasting process than on the original bean, meaning that some will be perfectly good (such as Illy brand), while others will be pretty nasty.

Again, it’s important to keep in mind that dark roast coffee does not equal a stronger caffeine content or necessarily a stronger flavor (just a more bitter one), so it really will boil down to preference.

Light roast coffee has a reputation in many circles for being ‘weaker’, but as you can see this is definitely not true. When it comes to flavor and aroma, light roast coffee is actually better tasting while caffeine content is the same whether you use dark or light. Dark wins in terms of an earthier, more bitter and smoother flavor with a lot less acidity while light roast wins for having a brighter, more flavorful profile. What does it all come down to? Your preferences! So, choose coffee that you enjoy or try out all different kinds until you find a favorite. Enjoy!

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