Often the coffee beans we buy from coffee shops in light, medium or dark brown in colour actually don’t pick off from the coffee plants exactly that way.
It is a heat processing called “coffee roasting” that turns the green coffee beans into those familiar brown colours. And the roasting happens as not all coffee enthusiasts enjoy the mild flavour of green coffee beans. Also, coffee roasting becomes certain to unwrap the aroma and the literal taste of those green beans.
Since the roasting process actually can be tailored depending on the preferences, so to understand your coffee roasting better and unlock your preferred flavour, knowing the variables of this roasting process thoroughly is vital.
Know your perfect roasting profile to decide roast degree and time
Finding your preferred roast profile is crucial since there is no existence of any ‘ideal roast profile’, and it varies from person to person’s taste preferences. For example, if you are a fan of complex fruity taste, shoot for lightly roasted coffee or if you need rich and intense flavour in your cup of coffee, pick the dark roasted beans.
Eventually, the roasting temperature and time put the biggest role in affecting the caffeine level and flavour. For a more balanced, low acidic and smoother taste, professional coffee roasters prefer slow roasting. On the other hand, fast roasting brings out that concentrated flavour for the people who are concentrated on getting much acidic tone in their coffee.
Let’s discuss some general roast types in detail.
The shortened roasting process is known as light roasts, where the green seeds are being exposed to heat only for a minimum amount of time just before or right after the first crack stage. When the roaster heat transfers to the coffee beans, in the first warm phases, the beans start transforming from green to yellow to light brown in colour, leading to the first crack of the beans. The lightly roasted beans hold more caffeine content and acidity despite being light in the body.
Once the beans clear the first crack, it prepares for another fracture which is the second crack. And the medium roasting occurs before this second crack, where many chemical changes occur, and the beans’ natural sugar start to caramelise, bringing a darker shade of brown colour. The medium roasted beans provide a more balanced flavour and richer consistency compared to the lightly roasted beans.
Immediate before or after the second crack, the medium-dark roasting happens and holds a much darker shade of brown that is near to dark. This roasting process brings out the oil of coffee beans’ and becomes visible in the surfaces that have been closed inside the beans. The medium-dark roasted beans hold less acidity and thicker consistency due to the long roasting time and bring out a bittersweet aftertaste.
Passing the second crack and taking the longest amount of time, the dark roasted beans are roasted until the beans turn into the colour of dark chocolate or become black. At this stage, the beans’ sugars become strongly caramelised and contain minimum acidity with the least amount of caffeine. However, even due to the long roasting process, the beans lose their original flavour and wear the flavour imparted by the roaster.
Understand the roasting phases and development
Now that you got the ideas of the basic roasting profiles, for a better understanding of the basic notions, have a clear idea about the roasting processes also. Therefore, let’s discuss the phases of roasting transformations in the following stages.
Before dropping the raw coffee beans into your coffee roasting machine, it is important to preheat the space. Preheating your roasting machine is vital to maintain consistent roast time and it ensures the even spread of heat within the machine. And to fix the starting temperature, you need to focus on the size of the roasting machine, amount and required characteristics of the coffee.
After preheating your roasting machine, you put your first batch of raw beans inside it, and this is when the roasting process begins. Usually, the green coffee beans are rich in moisture-holding much water in its body, and charging those beans in the preheated roasting machine works to drive those water by transforming into the stream. Once the coffee beans start absorbing heat, it starts turning from green to yellow, which you can mark as the end of the drying phase.
Since the beans have been dried out in the drying phase, the beans start to turn brown from yellow in this browning stage. The roasting process is taken slowly to let beans develop their flavour and create a distinct scent in this browning stage. And after some time, when the first pop of sound or what is known as the first crack occurs, it signals the beginning of the development stage.
In this phase, just as the name, the development and modulation of the coffee beans occurs by changing colours rapidly. This is where you can decide whether to go for a fruity flavourful high acidic light roasted coffee or pick a rusty and brunt low acidic coffee. And then, you can either stop roasting after the first crack or in between the first and second crack or after the second crack. Hence the time and temperature also fully depends on your preferred choice.
This is the phase that lasts till the final part of the roasting process by browning the sugar that coffee beans contain. So, the more you extend your development stage by roasting the coffee for a longer time, the more you will get caramelised and buttery beans that release acidic and aromatic compounds.
Which roasting machine is your best fit?
It varies. As for in-house roasting, people tend to use items such as a pan, popcorn popper or oven to roast the small batch of beans at home. But since they are not designed to roast coffee beans and might roast unevenly, you can go for a small size roasting machine-like medium drum roaster for your home roasting that provides better control and variability.
Or, in case you are planning to buy roasting machines that professional coffee roasters use to offer freshly roasted beans, pick machines such as classic drum roaster, recirculation roaster, fluid bed roaster, or any large machine that holds the capacity to roast a larger batch of beans at one time.
Though coffee roasting is a skilful task and learning to roast is eventually a boundless journey, these are some of the basic insights you can focus on to better understand your coffee roasting to achieve expertise.