Roasting Green Coffee
Coffee roasting is a crucial step in achieving the desired flavors and aromas in brewed coffee. It’s also important to note that roast level doesn’t affect caffeine levels.
Chemical Reactions of Roasting – Pyrolisis
The roasting process eliminates most of the moisture in coffee beans and triggers a series of chemical reactions known as pyrolisis. This changes the chemical composition of the coffee and develops the compounds associated with its flavors and aromas. Roasting is essential to making a great cup of coffee.
The Skills of the Roastmaster
As a skilled roastmaster, it is important to apply the proper temperature for just the right amount of time in order to bring out the best flavors of the coffee beans. Roastmasters need to be constantly monitoring the color of the roasting coffee beans, making sure they do not get too light or too dark. Additionally, as the coffee beans lose moisture, their density changes and needs to be taken into account.
Effects of Coffee Roasting
Coffee roasting can have a significant impact on the flavor, aroma, sweetness, acidity and body of the coffee. Roasting also creates new flavors and aromas and can stabilize existing ones.
Coffee Roasters, Roasting Temperature, and Roasting Time
Roasting coffee beans to perfection requires skill and the right coffee roaster. The roasting temperature typically ranges from 370 to 540 degrees Fahrenheit (188 to 282 degrees Celsius). Depending on the size of the roaster and the type of bean, roasting times can vary from 8 to 20 minutes. As the beans darken in color and become fragrant, they also shrink by about 20% in weight. For example, it takes about eight pounds of coffee cherry to yield one pound of roasted coffee (100 pounds of coffee cherry produces approximately 12 pounds of roasted coffee).
Caramelization During the Roasting Process
Caramelization is a process that occurs when simple sugars are heated to a specific temperature, creating a caramel flavor and color. It’s a natural byproduct of coffee roasting. The process of carbon dioxide gases releasing from freshly roasted coffee is known as degassing.
Continuous Fluidized Bed Roasting
During the process of making instant coffee, continuous fluidized bed roasting is often used. This process involves levitating the coffee beans on a cushion of hot air, which takes between 30 seconds and 4 minutes. Lower temperatures are used in this process, which results in better taste and aroma retention.
Factors Affecting Coffee Roasting Time
There are many factors that affect the roasting time of whole coffee beans, such as the roast type, bean quality, moisture content, and grade. Additionally, bean age and roasting conditions can also affect the roasting process.
It’s important for the roastmaster to monitor the roasting time and temperature, as well as other subtle indicators like appearance and smell. By doing so, they can ensure that the coffee is roasted to perfection.
First Crack and Second Crack
The roastmaster also pays attention to the popping sounds made by the roasting coffee. These distinct “cracks” indicate different stages of roasting, and there is a first crack and a second crack.
The first crack occurs at about 385 to 400 degrees Fahrenheit, which is usually just several minutes after the roasting begins. The coffee beans visibly expand in size as they make a cracking sound. Light Roasts are only roasted until the first crack.
The second crack occurs when the coffee beans reach about 440 to 450 degrees Fahrenheit and the cellulose matrix of the coffee begins to break down. This usually happens several minutes after the first crack, and the coffee beans will make a cracking sound again. Coffee beans roasted just to this point are usually considered a Full Roast (Medium-Dark Roast).
Coffee Roast Profiles – Standardization in the Roasting Industry
There is a lack of standardization in coffee roasting when it comes to factors such as roast types, roast profiles, and production methods. The roast profile of a coffee is a temperature graph of the beans during the roasting process.
The Four Primary Types of Roasts
There are four main types of roast, from light to dark: light roast, medium roast, medium-dark roast, and dark roast. The type of roast you want will determine the roasting time.
Light roasts are sometimes called by other names, including Cinnamon Roast, Half City Roast, Light City Roast, and New England Roast.
Medium Roast coffees are also known as American Roast, Breakfast Roast, Brown Roast, City Roast, Medium-Brown Roast, Medium High Roast, Regular Roast, and Standard American Roast.
Some of the most popular medium-dark roasts include After-Dinner Roast, Dark-Brown Roast, Full-City Roast, Full Roast, Light Espresso Roast, Light French Roast, High Roast, North Italian Roast, and Viennese Roast. These roasts are perfect for those who want a rich flavor with a slightly darker color.
Dark Roasts are also known as Black-Brown Roast, Continental Roast, Dark French Roast, Double Roast, Espresso Roast, European Roast, French Roast, Heavy Roast, Italian Roast, Italian Espresso Roast, Neapolitan Roast, New Orleans Roast, South Italian Roast, Spanish Roast, Turkish Roast, Very Dark-Brown Roast, and Vienna Roast.