The forgotten Coffee Roaster¶
About a month before the course comlpetion I decided to change the project. I had been thinking of making a coffee roaster, which seemed both complex and a lot of fun. I did not come to this idea on my own, in fact Maxime and I had been discussiong what else could I make other than the parachute system, and so he started by asking me questions to help me narrow down the choices.
This project did not come to realization… yet!
Coffee 101¶
Coffee comes from an evergreen shrub grown in tropical regions along the equator, also refered as the coffee belt. The plant produces fruit called coffee cherries, and the coffee bean is actually the seed found inside. To extract this seed, farmers use different processing methods that change the final flavor, such as washed, natural, honey, and anaerobic.
Most coffee comes from two distinct plant species known as Arabica and Robusta. Arabica accounts for most specialty coffee because it offers a sweet, complex flavor with vibrant acidity. However, these plants require higher altitudes and delicate care to grow. In contrast, Robusta plants are much hardier and thrive at lower elevations. Robusta beans contain nearly double the caffeine of Arabica, which creates a much stronger, more bitter, and earthy taste that is ideal for instant coffees and espresso blends.
Roasting¶
Roasting coffee is not so difficult as it seems to be… In fact, I am learning more as this project evolves. However it is important to understand that coffee, like any other fruit, is consumed best when it’s fresh.
When roasting, the two key elements to watch are color changes and the cracking stages.
Green: unroasted, raw beans.
Yellowing: the early stage of color change.
Light roast: the first brewable stage, pulled after the first crack.
Medium roast: the specialty coffee industry favorite, offering a balanced profile.
Dark roast: generally less preferred, roasted mostly past the second crack, has visible oils and surface cavities.
After the yellowing stage, a thin skin called chaff starts breaking off the bean. This debris is highly undesirable in both the roaster and the grinder. In a roaster it a potential fire hazard, whereas in a grinder, it ends up in your cup, creating an unpleasant, bitter taste profile.