For many coffee drinkers, the differences between dark roast, medium roast, and light roast are elusive. There are theories that the darker the roast, the stronger the coffee; however, that's not the case.
Roasting coffee beans is similar to cooking. One of the best ways to think about it is that the more the coffee beans are roasted, the more you taste the work of the chef or, in this case, the coffee roaster. The less the coffee beans are roasted, the more you taste the work of the farmer.
The master roaster is comparable to a head chef in a kitchen. They are responsible for creating the recipes and ensuring the production of all batches of coffee beans is consistent and of the highest quality.
Coffee Roasting Basics
While the size of a coffee roasting business will impact the supplies and equipment they have access to when roasting coffee beans, the basic processes are all the same to achieve drinkable coffee. When coffee beans first arrive at the roaster, they are hard, green, and lacking flavor. The roasting process is what gives coffee beans their flavor. Each coffee cherry produces two green coffee beans.
3 Main Roasting Stages:
Drying Coffee Beans:
The green coffee beans are high in moisture, containing anywhere from 10-12% water. Therefore, the drying process is essential to remove the excess water from coffee beans to enable the development of flavor in the following stages of the coffee roasting process.
Whether they end up being dark roast, medium roast, or light roast, all coffee beans will begin with this step. First, the coffee beans are placed in the roasting drum, and heat is used to remove moisture. This phase is complete once the temperature is 300° Fahrenheit and the coffee beans have turned from a green color to a yellow color.
Constant movement, in addition to a gradual increase in heat, is imperative to the drying process. Too much heat or coffee beans that sit still for too long can create hot spots. This presents as dark brown or black spots on the coffee beans. Hot spots on coffee beans will negatively impact the flavor and aroma of the coffee roast. Hot spots will also detract from the consistent cup of coffee we all crave.
Browning the Coffee Beans
In this stage of roasting, the aroma of the coffee beans is often compared to toasted bread, straw, hay, or cooked rice. The coffee beans experience something called the Maillard reaction. This reaction happens in all foods that are browned; think of toast, seared steak, cookies, or toasted marshmallows.
The Maillard reaction was first discovered in 1912 by the French chemist Louis-Camille Maillard. It refers to the chemical reaction between reducing sugars and amino acids that gives browned food its flavor.
During the cooking process, the Maillard reaction can create hundreds of different flavor and color compounds, and these compounds can then break down even further to create more flavor compounds. In addition to being used in the roasting of coffee beans, the Maillard reaction is used by food scientists to create many artificial flavors in foods and drinks.
The roasting process will slow down during the browning stage, and we get what coffee roasters refer to as the "first crack." The first crack is a literal term indicating when the coffee beans have split or cracked open. The first crack creates an audible popping sound, similar to when the popcorn pops.
So, what exactly causes the first crack?
First Crack: The first crack occurs when the remaining water is drawn into the very center of the coffee beans. The moisture builds intense pressure in the center of the coffee bean until it finally escapes, causing the crack.
The coffee roasting process typically has two cracks. The light roast and medium roast process will finish between the first and second crack; however, a dark roast will go up to or past the second crack.
Coffee Roast Development Stage:
The development phase begins at the first crack and goes through the end of the roasting cycle. The length of the roasting cycle will determine if the roaster is creating a light roast, medium roast, or dark roast. The longer the roasting cycle, the darker the roast.
Aroma compounds are fully developed during the development stage. Slowing down the roasting process is essential to avoiding an overly smoky or sharp flavor profile. The end result of the coffee flavor ultimately comes down to how long the coffee beans are exposed to heat after the first crack.
The longer the coffee beans are heated, the more caramelized the sugars and acids become, resulting in a less acidic coffee profile. This caramelization process is why a medium roast will have caramel flavor notes, and a dark roast will have chocolate notes, while light roast coffee will retain fruity and floral notes. In addition, the coffee beans themselves will become browner in complexion the more prolonged the roasting process and the darker the roast.
From Light to Dark Roasts
The roasting process is a highly specialized process that is dependent on the roaster. The master roaster uses their defined palette and feedback they receive from their consumers to artfully create premium roasts from the best coffee beans.
Many of the best coffee roasters in the business were self-taught in the beginning, honing their skills and knowledge in their homes before branching out into larger coffee shop settings.
In association with the Specialty Coffee Association, the Coffee Roasters Guild is an organization dedicated to developing and promoting the coffee roasting profession to create a more diverse community. With expansion and diversity comes the opportunity for growth and innovation in the world of coffee roasting.
Let’s break down each roast type from light to dark and discover what separates them from each other.
Due to a significantly shorter roasting time, light roast coffee will retain the majority of the coffee beans' natural flavors and heavily depend on high-quality coffee beans.
The most common traits in light roast coffee beans are:
- Lighter color coffee bean
- Enhanced acidity
- Floral notes
Light roasts tend to contain more floral aromas. With less roasting time, you are getting a coffee that most closely resembles the natural flavors of the coffee bean. The flavors reflected will be indicative of the environmental factors from the location the coffee beans were grown.
Light roast coffee beans will finish roasting shortly after the first crack. Aside from their light brown color, they will also have a matte complexion without any oils on the surface.
With less roasting time than a medium roast or dark roast, it translates to a more subtle "roasty" flavor. Light roasts boast a more dynamic fruit or floral flavor. It is perfect for drinking hot or cold.
Light Roast Alternative Names:
- Half City Roast
- Cinnamon Roast
- New England Roast
We recommend using the drip method, specifically the pour-over method for light roast coffee.
Slightly browner in color than the light roast, the darker color originates from the caramelization of the sugars inside the coffee beans. In addition to the color change, medium roast also has a more robust aroma than light roast coffee beans.
Similar to a light roast, a medium roast will not have any oils on the coffee beans; however, it will typically be sweeter than a light roast due to the caramelization process. Medium roast coffee beans will have more body and more balanced acidity. Although all coffee will have some level of acidity due to the chemical reactions necessary in making coffee, the length of roasting time will determine the acidity levels.
The original process for roasting coffee beans consisted of putting the coffee beans directly to a flame. For this reason, the dark roast was the first type of coffee roasting attempted on coffee beans, and it was the standard for many years. On the other hand, the medium roast was the first attempt at roasting coffee beans to appeal to a broader array of potential coffee drinkers.
Advancements in coffee technology led to the shift in coffee culture, where creating specialized roasts and blends to cater to different taste buds began to take center stage.
Medium Roast Alternative Names:
- City Roast
- Full City Roast
Cold brew is our recommendation as to the best brewing method for medium roast coffee beans.
The original. The oldest roasting style for coffee beans. Dark roasted coffee beans can run the risk of being roasted for too long and then producing a burnt taste. Far too many people have experienced a burned cup of coffee, and it has turned them off from dark roast completely.
To reach the ideal dark roast, the internal temperature of the coffee beans should reach 464° Fahrenheit. This temperature is typically reached at the end of the second crack or afterward, depending on the roaster. Roasting for too long after the second crack or not diligently monitoring the temperature of the coffee beans can lead to overcooked and burned dark roast coffee beans.
A high-quality dark roast will not taste burned at all; it will have a strong aroma with a smooth and chocolatey flavor. The bean itself will be darker than a medium roast and will have a shiny, oily finish that will differ from light roasts and medium roasts.
A dark roast is classified by low acidity, a heavy body, and sweet flavor notes. In addition, a great dark roast coffee will have a thicker body due to the oils on the coffee beans. Most people envision diner-style coffee when thinking of a dark roast coffee.
The myth that dark roast coffee is stronger than a medium roast or light roast can be traced back to two things:
- Flavor Profile
- Preferred Brewing Style
Flavor of Dark Roast:
The dark roast boasts a thick body and bold chocolatey aroma compared to the bright fruit and floral flavors found in light roast coffee beans. When comparing the heavy chocolate with bright florals, it can be easy to see why some might consider the dark roast to be stronger than a light roast, but in actuality, they are similar in strength,
The most popular coffee for making espressos are dark roast coffee beans. An espresso shot has 63 milligrams of caffeine per ounce, while a standard cup of coffee has 16 milligrams per ounce. This increased level of caffeine is attributed to the brewing style, not the coffee bean roast.
Light roast, medium roast, and dark roast coffees all have comparable amounts of caffeine. The roasting process does not positively or negatively impact the level of caffeine in the coffee beans.
The dark roast coffee beans are the most versatile when it comes to brewing style. Due to spending so much time in the heated roasting process, they are able to withstand high heat while brewing. This is what makes them ideal for making espresso but also perfect for making a pour-over coffee.
Dark Roast Alternative Names:
- Full City Plus Roast
- Italian Roast
- French Roast
We recommend dark roasted coffee beans for espressos and cold brew coffee brewing.
Dried, Cracked, and Roasted to Perfection
The roasting process is instrumental in creating the ideal cup of coffee, turning green coffee beans into your perfect cup of Joe. However, discovering your favorite roast of coffee goes beyond finding the ideal coffee shop; it traces all the way back to where the coffee beans originated from.
When drinking a light roast coffee, the origin of the coffee beans plays a pivotal role in the flavors and aromas that are captured and brought to life. When drinking a medium roast or dark roast coffee, the master roaster is instrumental in creating a beautiful cup of coffee.
The role of the master roaster is a serious job that requires attention to detail, patience, and an understanding and appreciation for nuance. They use their highly honed skills to create masterful coffee roasts that make for the perfect cup of coffee—truly a gift that keeps on giving.