The right roasting process is decisive
The unique aroma and the flavour of each bean typical for this type of coffee is the result of the roasting process and chemical reactions that occur during this process. During the grease-free and dry roasting process up to 800 aromatic substances contained in the coffee beans are revitalised.
Roasting time influences the moisture as well as the acidity of the beans. The darker the roast, the less acidity, but the more bitterness and sweetness is released. Temperature development and roasting time therefore influence the aroma and flavour of the beans. This means that the same type of bean can taste differently depending on the parameters of the roasting process. As only flavour substances that are present in the untreated bean can be released during the roasting process, every roasting process must be perfect for the blend of beans. Only then can the whole flavour pallet of a bean develop and unfold.
As the moisture in the bean evaporates during the roasting process, its water content reduces from originally approx. 12% to only 5%. The bean's weight also reduces. But those who now think that this would result in the bean shrinking, is mistaken: its size doubles during the roasting process as the evaporating water increases the pressure inside the bean.
During the roasting process of Miele's Black Edition N°1, the untreated coffee beans are poured into a pre-heated roasting container. This dries the beans and pre-warms them. Then they are roasted during which the first aromas develop from approx. 150°C. At the end of the roasting process the coffee is at least 180°C hot before it is cooled down.