Roasting

Green coffee is, well, green and hardly tastes like familiar coffee. Only during roasting at high temperatures do chemical reactions such as the Maillard reaction and caramelisation take place. The beans turn brown, lose water, expand and develop hundreds of aroma compounds.

Roasting time and final temperature determine the roast level and with it acidity, bitterness and body. The same green coffee can taste very different depending on the roast. Freshly roasted coffee still releases gases and is often left to rest for a few days.