At the crossroads of art, craft and science...

Roasting blurs the boundaries of art, craft and science. Roasters can dose each element as they see fit to create their own unique style, their trademark. It is a conscious act taken to impart a personal vision of a coffee among its consumers. It is therefore difficult, if not impossible, to assess a roast without understanding the overall context, which is the synthesis of the roaster’s entire thought process and culminates in an aromatic profile for a given cup, a given coffee. We need to understand their roasting intentions, target audience and chosen coffee.

A profession of choice

This article aims to explain how roasters use their know-how to achieve diversity. It would be far too simplistic to reduce their work to the mere act of roasting. It begins with careful selection of a green coffee, which requires knowledge of the origin (specific features of a terroir, species, botanical variety, process), sensory analysis (organoleptic analysis of the coffee, roasting projection), the problems encountered by business owners (strategy, range issues, price-target correlation) and personal vision (identity, values, contribution to the industry).

Knowing the variables

Roasters then proceed as they would for a food recipe, managing numerous factors to enhance their coffee. They begin by building a clear picture of the variables affecting the roasting process. The main ingredient is the green coffee itself, which has its own identity card. The roaster must understand its aromatic potential, based on the terroir, species, botanical variety and process (nothing more frustrating than searching for aromatic notes that simply don’t exist). Knowledge of physical data (density, moisture content, screen) is equally important, to develop the coffee during roasting. Other ingredients make additional contributions, and must be included in the equation. 

Depending on the season

Our climate (still) offers four seasons, and the humidity level of ambient air plays a large role; a same coffee can deliver different results depending on whether it is roasted in March or July. Coffee storage, machine design, preheating time and heating protocols between different roast batches will also leave their mark. Roasters must know, control and experiment with coffee roasting variables to proceed with confidence, the most important being start temperature, exit temperature, total roasting time, energy management and development time after the first crack.

Depending on how the green seed develops

The transformation of green beans is observed clearly during roasting. There are three distinct phases, one visual, one olfactory and one audible (coffee roasters are lucky compared with roasters of cocoa beans, which do not change colour and do not crack). The yellow point is a visual and olfactory (sweet nuances of brioche or cereals) signal of the transition from the drying phase (first phase) to the “chemical reaction” phase (particularly the Maillard reaction and sugar browning). Then the bean makes itself heard with a first crack, announcing the beginning of the third phase, the development phase, and hence the end of roasting. Roasting is a continuous process consisting of these three interrelated phases, which must be understood and optimised to achieve a desired result.

By measuring roasting data

The post-roasting stage begins with measurement of data, including weight loss after roasting, colorimetry and quality-control cupping. In reality, these controls are often skipped or overlooked due to time constraints. Many roasting shops focus on offering and selling coffee (packaging being another essential and time-consuming step). It’s all a question of priorities. Some believe this to be a less important, or too laborious step, reserved for only one type of roaster. Whatever the reasons, post-roast cupping should be a routine roasting shop practice. Methods exist to make it more accessible and effective (something Belco will be happy to help you with). It’s essential for better understanding a green coffee (e.g. ageing), for achieving a desired aromatic profile (further refining the profile with each roast), and for creating a unique and personal roast and advising customers. It’s essential for better understanding the relationship between your roasting machine and the coffee in the cup. 

The profession of roaster is complex, and each step is essential. The transition from green coffee to sale can be explained easily and understood in just five minutes, but mastering these steps may take more than a lifetime. It is not a linear profession, and each coffee, each roast can be a pretext for improving skills.

Experience is valuable but not necessarily equal to the number of hours spent behind a machine.

While respecting his state of mind

The most important consideration must be state of mind, ability to question and experiment (as far as economically possible), sharing of experiences with peers, customer insight and cupping (again and again!). Ultimately you will be able to explain your choices, from green coffee and roasting recipe to selection of an aromatic profile and customer experience.  More generally, it’s also a question of accepting a continuous improvement dynamic, which will probably raise many questions but will also provide answers, and contribute to your progress.  

What guides and drives us as roasters? The answer will be as fascinating as it is personal. But we will agree on some things: a desire to promote diversity in our coffee industry, a desire to communicate its values, and a desire to project our own personal vision of coffee through our roasts.

And of course cupping, the only language shared by producers, sourcers, roasters and customers alike… so let’s cup, communicate and collaborate!

In sum, there is no right or wrong roast, just a variety of messages showcasing our roasting profession. And above all coffee, all coffees.