Coffee bean roaster works best when you know how to roast.
Knowing how coffee bean roaster works would determines the strength, taste and even caffeine content on your next espresso or coffee. Even if you are using a electric roaster, knowing the roasting process would equipped you with the knowledge to roast different category of beans, allowing you to enjoy a variety of flavors.
The process begins when the heat source from coffee bean roaster is applied to the green coffee beans inside the drum or cannister. And usually, there would either be spinning or rotating to roast them evenly. 290 degree celius is a benchmark temperature and depending on the type of roast, it might go lower for lighter roast and higher for darker roast.
** Sounds complicated? Fear not, the whole process would go unnoticed in most home coffee roaster as most of its process is in auto-mode and you would not have to do a single thing other than pressing some buttons!**
This heat creates chemical changes in the physical structures and composition of the beans.
The changes begins when the Water evaporates from the beans. Here, the starches are convert to sugars and the sugars caramelize. And for those that have looked through the windows of coffee bean roaster, you would noticed that The beans increase in size by 25 to 35%.
As the coffee bean roaster begins to turn and heat is added, the green beans turn a yellowish color, then darken to a deep rich brown.
This is due to other chemical reactions that happens when the beans' sugar and proteins interact with each other. These chemical reactions releases caffeol, or coffee oil, the element responsible for bringing out the flavor and aroma of the beans. The darker the beans, the more oil they produce.
Do note, at all times as heat is being applied to the beans, the spinning and turning in a coffee bean roaster is essential, more so as the process is finishing to ensure that the already heated beans are not burnt.
Then as the beans turn into a medium-dark roast, flavorful acids is formed . As the roaster produces a darker roast, the flavorful acid will begin to break down, and the sugar components will start to caramelize. And that is the reason, why a darker roast has more body and an intense richer flavor to the palate.
Coffee drinkers, like yourself would know that espresso beans are characteristically lower in acidity, richer in body, and taste to a slight degree like caramel(caramel, is after all, just roasted sugar)-yup, they are the darker roast beans... After this monitored roasting process, the coffee beans have to be rapidly cooled down by cold air. This is to seal in all flavor and aroma that the reaction has given to the dormant green beans.
So, what does all these roasting process means to you -someone who just wants to enjoy that cuppa? Well, either you are choosing or even using a coffee bean roaster at home, you would know this:
A lighter roast has more flavor acids, resulting in interesting flavors and taste. This category of roast are lighter in body as the roast has not produced caramelized sugars or caffeol
Then, medium roast would have less acidic snap but they are richer and comes with a more rounded flavor. This is mainly due to coffee oils coming out from the roasting.
And when the beans reaches the dark roast stage, all the acidic tones disappear and the beans becomes oilier. This results in a definite bittersweet, chocolaty flavor. And your cuppa would be rich and full in body and texture.
Now, one final trivia for drinkers that would be using a coffee bean roaster. If you are thinking of decaf or drinking less caffeine -roast the beans longer. As the darker the roast, the lower the caffeine level. Hence, higher and longer roasting temperatures eliminate more caffeine from the beans than will a brief, cooler roast.