Coffee roasting is a complex process that involves the careful application of heat to green coffee in an effort to transform the basic stuff of life contained within each seed – sugars, proteins, acids, etc – into delightful aromas of roasted nuts, malts, chocolate, fruit, berries, flowers and more. We take great care with each coffee, blending scientific data logging with intuition and experience to bring out a balanced taste and optimal flavour.
Step 1. At the beginning of each batch, raw “green” coffee is loaded into the roaster’s charge system. Once the roaster’s internal air temperature reaches 500F the batch is dropped into a spinning, hot drum to begin the roasting process. Inside the drum there are many paddles that toss the coffee through the air – this is similar to how a household clothing dryer works.
Step 2. For the first 5 minutes, a high amount of heat is applied to bring the coffee up to roasting temperatures. This stage has to be done quickly enough to preserve some internal moisture but not so quickly that the outside of the beans are at risk of scorching. The colour of the coffee shifts from green to yellow and the smell shifts from freshly cut grass to hay-like.
Step 3. In the next 5 minutes the coffee undergoes changes at low roasting temperatures (between 300F and 350F). “Precursers” to tastes and aromas that will develop at higher temperatures are developed and the internal moisture, pressure and temperature are carefully controlled. The colour turns from yellow to light brown and the smell turns from hay-like to that of baking bread.
Step 4. During the final 2 to 5 minutes (depending on the type of coffee and roast degree) the coffee’s full flavour is developed. At around 360F the “first crack” occurs – a popping noise occurs as each bean expands under the pressure of carbon dioxide and water vapour produced from chemical reactions within the bean. At this point the internal pressure drops as these gases are allowed to escape, resulting in a bean with an ideal internal temperature, pressure and moisture for flavour
Step 5. Between 360F and 395F the sugars and amino acids in the coffee react at a rapid pace to create the final flavour of the coffee. The flavour of coffee roasted to a “medium roast” degree is derived from carmelization of sugars and the reaction of sugars and amino acids in the “maillard reaction” – very similar to the flavours developed through the browning of meat on a grill. During this period the coffee turns toward darker shades of brown and the aroma develops into a nutty, cocoa-like and malty character.
Step 6. Each coffee has a precise final temperature and time of roasting, both developed through a mixture of intuition and experimentation on the part of the roasting team. For example, a Yirgacheffe coffee might be roasted to 380F in 12:30, while a Honduran Espresso coffee will be roasted to 389F in 14:30.
Step 7. Coffees roasted to temperatures above 395F are considered to be dark roasts. At these temperatures the aromas and tastes developed during the initial stages are combusted and new aromas that are toasty, smoky and spicy develop. Sweet and acidic tastes are replaced by the development of bitters. Most dark roasts develop to between 410F and 420F to achieve full development of these characteristics.
Tips on Coffee Roasting
Coffee roasting is a complex and dynamic process that involves a number of variables. In order to produce a great cup of coffee, it is important to understand the basics of coffee roasting. This essay will provide an overview of the coffee roasting process, including the different methods used, the importance of roasting temperature, and the role of time in the roasting process.
The Different Methods of Coffee Roasting
There are a number of different methods that can be used to roast coffee. The most common methods are drum roasting and air roasting.
Drum roasting is the most common method of commercial coffee roasting. In this method, the coffee beans are placed in a rotating drum that is heated by a gas or electric flame. The beans are roasted evenly as they tumble in the drum.
Air roasting is a less common method, but it is gaining popularity due to its ability to produce a more consistent roast. In this method, the beans are roasted in an air roaster, which uses hot air to roast the beans. The beans are roasted evenly as they are circulated in the hot air.
The Importance of Roasting Temperature
The temperature at which coffee beans are roasted is important for two reasons. First, the temperature affects the flavor of the coffee. Second, the temperature affects the level of caffeine in the coffee.
Coffee beans roasted at a higher temperature will have a more intense flavor. The higher the temperature, the more intense the flavor will be.
Coffee beans roasted at a lower temperature will have a less intense flavor. The lower the temperature, the less intense the flavor will be.
Coffee beans roasted at a higher temperature will have a higher level of caffeine. The higher the temperature, the higher the level of caffeine will be.
Coffee beans roasted at a lower temperature will have a lower level of caffeine. The lower the temperature, the lower the level of caffeine will be.
The Role of Time in the Roasting Process
The length of time that coffee beans are roasted also affects the flavor of the coffee. The longer the beans are roasted, the more intense the flavor will be. The shorter the beans are roasted, the less intense the flavor will be.
Coffee beans roasted for a longer period of time will also have a higher level of caffeine. The longer the beans are roasted, the higher the level of caffeine will be.
Conclusion:
In conclusion, it is important to understand the basics of coffee roasting in order to produce a great cup of coffee. The different methods of coffee roasting, the importance of roasting temperature, and the role of time in the roasting process all play a role in the final flavor of the coffee.
