{"id":14470,"date":"2021-04-02T14:44:44","date_gmt":"2021-04-02T12:44:44","guid":{"rendered":"https:\/\/www.coffeedesk.pl\/blog\/?p=14470"},"modified":"2021-04-02T14:44:44","modified_gmt":"2021-04-02T12:44:44","slug":"how-is-the-coffee-roasted-the-basics-of-coffee-roasting","status":"publish","type":"post","link":"https:\/\/www.coffeedesk.com\/blog\/how-is-the-coffee-roasted-the-basics-of-coffee-roasting\/","title":{"rendered":"How is the coffee roasted? The basics of coffee roasting"},"content":{"rendered":"

The boom in the specialty coffee industry has been on for several years. Baristas are tirelessly gaining experience, broadening their knowledge of coffee, honing their skills, and mastering modern techniques. Over time, their profession has become more and more interdisciplinary. However, my impression is that the increase of professionalism is missing one of the basic coffee-related areas. It seems to me that baristas know more about botanical varieties<\/a>, terroir or processing methods<\/a> than they do about roasting coffee. This is no surprise \u2013 a lot of reliable, basic information about what is happening on the plantations is available online. Whereas roasting is still largely treated like a secret knowledge<\/em>, a craft for the chosen ones. So, what is coffee roasting and how does it look like? Let\u2019s find out!<\/strong><\/big><\/p>\n

Why so secret?<\/h2>\n

Lighter roasting of high-quality Arabica<\/a> in craft roasteries is a new and, therefore, still underdeveloped area. Everything was trivial as long as all coffee was roasted dark, and, consequently, every brew tasted very similar.<\/p>\n

The famous third wave of coffee<\/i> forced the roasters <\/b>(i.e. people who roast coffee, editor’s note) to significantly expand their knowledge, develop analytical and sensory skills, and gain a lot of patience and humility. Hundreds of theories are analyzed every day on geek forums for roasters. Among them: truths, half-truths, understatements, myths and incorrect assumptions. One person says one thing, the other says otherwise. The third one overthrows both foundations, and the fourth one counters all three, convinced that he is right. Some roasters cooperate with each other and share even the smallest variables, others treat their conclusions and profiles like little Amber Rooms. Knowledge is largely passed on in closed master-student relationships. Otherwise, it is gained from several published books, none of which has so far been a decent and comprehensive compendium of knowledge from A to Z.<\/p>\n

\"green
Green, raw coffee, just before roasting. \/ photo by HAYB<\/figcaption><\/figure>\n

Finally, the techniques and styles of roasting coffee that provide the desired results are relatively numerous. Let’s add local preferences to that. Roast from Solberg & Hansen <\/a>or\u00a0 Johan & Nystrom<\/a> can be considered undeveloped and sour in the United States. And in Goteborg they will say that Melbourne coffee is definitely too dark and bitter…<\/p>\n

Let’s put it all aside for a moment. It would be nice if the basic information on coffee roasting was available to as many people as possible. I will try to present some of the foundations of roasting in a simple form and, I believe, paint an elementary picture of what it is all about.<\/p>\n

Roaster<\/h2>\n

Coffee is roasted in specialized roasters. Shocking! The vast majority of them are the so-called drum roasters. They are usually powered by fuel in the form of flammable gas. The most important element of such a machine is:<\/p>\n

Drum<\/h3>\n

It\u2019s a bit like in a washing machine. It\u2019s cylindrical and it spins. Inside the drum there are paddles, which scoop the beans to ensure them an even, cyclical, rotational journey through the roasting process.<\/p>\n

\"coffee
Coffee roaster at the end of the roast. \/ photo by Lumina \/ Stocksy \/ Adobe Stock<\/figcaption><\/figure>\n

Flame<\/h3>\n

It is located directly under the drum. It turns the fuel supplied to it into a flame, the intensity of which is controlled by the operator. The flame is a source of energy – it heats the drum to the desired temperatures, which roasts <\/span><\/i>the coffee.<\/span><\/p>\n

Cooling tray<\/h3>\n

Placed directly under the exit, through which the roasted coffee is dropped at the right moment, thus completing the roast. It\u2019s necessary to cool the beans in order to stop the chemical reactions that have just taken place in them as quickly as possible. Therefore, just before the drop, the operator starts the mixer and a separate engine which draws in the air from the environment, cooling the heated material. The mixer arms, similar to the blades within the drum, ensure even distribution of the coffee beans during the roasting process.<\/p>\n

\"how<\/p>\n

Chimney<\/h3>\n

A simple thing \u2013 hot air roasts the coffee, it goes through the drum and has to get away somewhere. Part of the dust and suspended particles from the raw material and the smoke generated in the final stage of roasting also get away with it. So does the air, transported through a separate channel, which cools the beans.<\/p>\n

Panel<\/h3>\n

For clicking, starting, changing and switching. It\u2019s the roasting command center, captain’s bridge.<\/p>\n

The roasting process<\/h2>\n

Coffee is a strikingly complex raw material. It is estimated that there are over 1,000 chemical compounds in roasted Arabica beans. Over 700 of them are odorants, i.e. substances responsible for the aroma impression. Even relatively small changes in the pool of substances contained in the beans will bring out completely different characteristics in the ground coffee, not to mention the brew. This is a chemical explanation for why we can easily sense the differences between the Kenyan SL 28 and the Peruvian caturra.<\/p>\n

Strecker, trigonelline, sugars, acids, amino acids and lipids degradations, caramelization, Maillard reactions… This is just a small share of the most important processes taking place in roasted coffee, the complexity of which is a major headache for many chemists. Two of them have actually told me that. This is not the place and time to delve into the detailed depths of these phenomena, but here\u2019s some interesting trivia.<\/p>\n

Sensing specific aromas in coffee is not just fancy hipsterism. Here are some popular aromas in the specialty-quality Arabica and the chemical compounds behind them, formed during the syntheses:<\/p>\n