Dark roast vs. medium roast: The differences you’ll notice

Dark roast and medium roast coffee beans
Share on email
Share on facebook
Share on twitter
Share on reddit
Share on pinterest

If you’re a casual coffee drinker, you may be passingly familiar with the idea of different roast levels. You’ll see coffee advertised as light roast, medium roast and dark roast.

Most coffee drinkers drink either medium or dark roast. And you may have picked a roast to drink, but may not fully understand the difference between dark roast vs. medium roast.

The most basic difference between the two is that a dark roast is roasted longer than a medium roast. The extra roasting time causes the resulting coffee to have a bolder taste with less acidity. However, that additional roasting also removes much of the individual flavour and character of the coffee beans in question.

With a medium roast, you’ll be more able to taste the distinct characteristics of whatever type of coffee bean was used to make your coffee. With dark roast, the roasting process standardizes much of the flavour.

How coffee beans are roasted

Roasting coffee beans gives them the complex flavours we enjoy once they’ve been brewed into coffee.

Coffee beans are usually roasted on a large scale commercially. However, an increasing amount of coffee is roasted in small batches by boutique or specialty coffee producers. You might be surprised how easy it is to roast coffee at home.

For professionals, there are two main types of coffee roasters: drum roasters and hot-air roasters. Drum roasters work by tumbling coffee beans within a drum while heating them. Hot air roasters blow hot air up through a screen or grate into the coffee beans, causing the beans to circulate and swirl within the current of the air.

Roasting coffee beans in a drum roaster
Smoke rises from a drum roaster as coffee beans are roasted. (© Cocoa Dream | Flickr)

Regardless of the type of roasting equipment, the raw coffee beans are roasted until they reach the desired level of doneness. Then they’re cooled and ground before being brewed. Coffee beans are often ground by the same commercial entity doing the roasting, though they are often sold as whole beans as well.

The stages of a coffee roast

The first stage of coffee roasting begins as beans just start to heat up. They’ll turn pale in colour, sometimes even white. At this stage, the beans are absorbing heat, but no significant chemical or physical changes have taken place.

During the second stage of roasting, the beans begin to shift in colour from a yellow to an orange or tan color. Now, we begin to observe chemical changes, as the coffee bean experiences both the Maillard reaction and caramelization. The aroma of the roast deepens from a grassy smell to something sweeter and more savoury.

Coffee roasting in a wok on the stove
Pale beans begin to take on a tan colour in the early stages of a stovetop roast.

The next stage of roasting is the first crack. At this point, the beans will audibly split with a cracking sound. The body of the beans will also begin to puff up. If you remove the beans from heat right at first crack, this is referred to as light roast.

The next stage of roasting covers the period in time between first crack and second crack. During this period, the flavour of the coffee changes considerably over a relatively short period of time. Even 15 seconds longer will change the coffee’s taste. Removing the beans from heat between first and second crack gives you medium roast coffee.

Medium roast coffee beans
Medium roast coffee beans. (© Benjamin Zeman | Flickr)

The next stage in roasting is second crack. Here, the coffee again pops or cracks, and oils have begun to migrate from the interior of the beans to the surface. Coffee removed from heat after second crack is dark-roast coffee.

Dark roast coffee beans
Dark roast coffee beans. (© Benjamin Zeman | Flickr)

Physical and chemical changes of coffee beans during roasting

As it roasts, coffee undergoes a series of physical and chemical changes. These changes greatly impact the flavour of the resulting coffee, and are also reflected in the appearance of the beans.

Probably the most fundamental chemical change in coffee beans as they roast is the Maillard reaction. The Maillard reaction is a process by which amino acids and reducing sugars create a distinctive range of tastes and flavours. All roasted coffee experiences the Maillard reaction. Caramelization is another chemical change during the roasting process, resulting in a sweet and nutty flavor.

In addition to chemical changes, the coffee beans undergo physical changes. After first crack, a process called pyrolysis occurs, which releases carbon dioxide from the bean and reduces its weight by 13 to 18%.

After second crack, oil from the interior of the coffee bean makes its way to the surface. That oiliness could be visible both on the bean and in the resulting coffee.

Taste of dark roast coffee vs. medium roast

A raw coffee bean is extremely acidic, and doesn’t even hint at the traditional coffee taste that most coffee drinkers enjoy. During roasting, the acidity is lessened and more flavours are promoted from the bean.

A medium roast retains some of the bean’s acidity, as well as some of the distinctive flavour of whatever strain of coffee bean was used. For this reason, those who buy expensive or highly-regarded single-origin coffee beans prefer a medium or even light roast.

A dark roast has very little acidity and a much bolder taste. The dark roast flavour tends to be deeper and darker. Traditionally, dark roast was used to mask the taste of substandard coffee beans, but now many coffee drinkers prefer the standardized, heavily roasted flavour to lighter roasts. It mixes especially well with milk or cream, making it popular bean for espresso drinks. Try it with your next flat white or cappuccino.

Pouring milk to make a cappuccino
Coffee made from dark-roasted beans mixes well with milk to make drinks like cappuccinos and lattes.

Which has more caffeine: dark or medium roast?

A number of myths exist about how roast level relates to caffeine content. Some people swear that dark roast has the most caffeine, while others say the opposite.

The truth is that there’s a negligible difference in the amount of caffeine from medium roast to dark roast. The process of roasting coffee beans does not meaningfully change the caffeine content.

The slight difference in caffeine levels may be due to the fact that dark roast loses the most volume in each bean while roasting. Since the beans aren’t as dense, there’s slightly less caffeine.

However, for all intents and purposes, medium and dark roast have comparable levels of caffeine. Neither will give you more caffeine jitters than the other.

Why are dark roast coffee beans sometimes shiny?

Raw coffee beans contain oils inside the bean. At lower roast levels, those oils remain locked inside. By the second crack stage of the roasting process, the interior of the coffee bean has begun to break down.

Oily coffee beans
That shine on dark-roasted coffee beans comes from oil that has made its way to the surface.

Now, those oils make their way toward the surface of the bean. If you take a look at unground dark roast, the beans often have an oily sheen to them. Oily coffee beans are perfectly natural in a dark roast. This oiliness will persist through the brewing stage to the cup of coffee.

Choose the one that suits your taste

The choice of dark roast vs. medium roast comes down to your expectations for the flavour of your coffee. If you prefer a more acidic, more subtle coffee that retains the character of the coffee beans, you’re better off going with medium roast.

If you prefer a less acidic, bolder coffee with the deep, rich taste often associated with traditional coffee, dark roast is your best option.

In the end, there’s no difference other than taste. You won’t get more caffeine from one or the other, and there aren’t any health factors to separate the two. It’s even possible to appreciate both for certain occasions. Many people enjoy dark roast for their daily coffee while choosing medium roast when they have access to premium coffee beans.

Welcome to Bean Poet!

We’re here to help you make and enjoy better coffee. We aren’t coffee snobs, but if you want to become one, this isn’t a bad place to start. Please know that as an Amazon Associate, we earn from qualifying purchases. This may also be true for links that lead to sites other than Amazon. You can sign up for our occasional newsletters below.

Featured

What is French roast coffee?

The English came up with the name, and it has nothing to do with where the beans were grown. Here’s all you need to know about French roast coffee.

2 thoughts on “Dark roast vs. medium roast: The differences you’ll notice”

  1. Thanks for the information. Now I know why I like dark roast best — I don’t like an acid taste. And my husband can’t tolerate acidic things, so now I know I’m better off giving him dark roast, which I had thought would be stronger in all ways. Great site!

    Reply
  2. Good points about the differences between dark roast and medium roast. Another roast to consider is white roast, i.e. most often called “White Coffee”. White coffee is weird. It doesn’t even taste like coffee. If the roaster roasts the bean too light (yellow) then the bean tastes like straw. But if the bean is roasted to a golden color, then the coffee tastes very nutty and wonderfully smooth. It’s very tough to find whole bean white coffee, but you can find it on the internet if you search for “Whole Bean White Coffee”.

    Reply

Leave a comment