Torréfacteur de café de spécialité de Montréal 94 celcius

Getting Started in Coffee: The Basics of Roasting

published on September 08, 2024 — by Marc-Alexandre Emond-Boisjoly — 15 mins of reading —

You have just received your precious bag of 94 Celcius coffee and you have a whole bunch of questions?

Our Getting Started in Coffee series is here to help you take your first steps into the world of specialty coffee. We’ll cover topics like storage, extraction , and roasting basics, among others.

Welcome, and above all, don't hesitate to ask us your questions!

Understanding Coffee Roasting

You like your coffee roasted darker for increased intensity, or lighter for fruitier notes. But do you know what a dark roast entails? How does roasting coffee help reveal its full potential?

Therein lies the art of roasting!

In this article, we will introduce you to the basics of roasting.

What is roasting?

Roasting is the process of cooking coffee (as well as other organic materials such as cocoa or nuts) to reduce its moisture content and develop its flavors.

The roaster is a key piece of equipment in this process, consisting of a drum in which the green beans are placed, rotated, and heated. Historically, the heat source was wood or coal placed under the drum. Today, roasters use modern heat sources, such as electricity or gas, which influences how the beans cook and, therefore, how their flavors develop (similar to the difference in cooking between an electric oven and a gas oven).

In the specialty coffee world, roasting typically lasts between 9 and 12 minutes . During this short time, the beans go through several stages of processing:

Color change : from green-gray to yellow, then to orange, and finally to brown.
Weight loss : approximately 16% of initial weight.
Change in texture : the grains swell, become porous and more digestible.

These transformations are linked to various chemical reactions which allow the development of the unique aromas of coffee.

Courbe de torrefaction du torréfacteur 94 celcius

Small glossary of roasting

To perfect the cooking of coffee, the roaster develops and follows a timed recipe that highlights the specificities of the bean. Here is a small glossary to help you better understand the cooking of coffee

Roasting profile = reference curves for cooking coffee. This set of curves will allow you to know when to make changes in gas or air or temperature so that the bean arrives at the desired temperature in good time. It is worked like a recipe and will depend on the bean (origin, variety, post-harvest treatment) and the type of roasting desired (see next section).
Drying phase= first 5-6 minutes of cooking. During this phase, the grain will lose some of its moisture and turn from green-gray to yellow.
Maillard phase= phase during which the Maillard reaction will occur. This is a chemical reaction inside the bean that will allow it to change color and develop its aromas and taste. The length of this phase will greatly influence the acidity and the final texture in the cup.

First crack= the grain will “pop”, a bit like popcorn. The grain has swollen with gas linked to the Maillard reaction and will crack to let it escape. This moment is very important to note on the roasting profile because it will mark the beginning of the development phase. It generally appears between 198 and 200 degrees Celsius.
Development phase= time between the first crack and the end of the roast, lasts between 1.10 minutes and 2.30 minutes. During this phase, also called the caramelization phase, the essential oils of the grain will begin to develop and want to extract themselves from the grain. This phase is crucial because it will define the desired sugar level and allow the full development of the aromas. A development phase that is too short will not cook the grain enough, which risks having a lot of acidity and a taste of hay. On the contrary, a longer development phase will develop more caramel and sugar aromas. Finding the ideal development time is very important to obtain the best balance in cooking the grain.
End of cooking temperature= target bean outlet temperature. This temperature will determine the degree of roasting of the coffee (light, medium, dark), but only partially determines the type of roasting (filter or espresso).

Once the right temperature is reached in the right time, the grain is cooled quickly to prevent it from continuing to cook.

Filter or espresso roast?

Here is the long-awaited question!

How is the roast type determined?

It is not the color of the grain that will give this information. This final color depends on the variety of the grain, its cultivation altitude and its post-harvest treatment.

Determining whether a roast is better suited for espresso or filter is a combination of development time and end-of-roast temperature. As seen above, during the development phase, essential oils will begin to migrate to the surface of the bean and begin to caramelize, and the bean will also become more porous.

An espresso roast will favor a slightly longer development phase (2 minutes or more) and a higher end-of-cooking temperature. The bean will have developed more sugar and will be easier to extract.

A filter roast, on the other hand, will favor a shorter development phase, to preserve the more acidic and delicate aromas, and a lower end-of-cooking temperature.

But these are obviously only estimates. Everyone will play with the different parameters to find their best recipe.

Conclusion

Roasting is the art of getting the best out of each coffee bean in 3 main phases: drying it, developing its aromas and achieving the exact balance between temperature and cooking length. An excellent roast will reveal the characteristics of the terroir and the variety of coffee, whether it is light or darker.

There is no standard recipe, each roaster has their own way of approaching the green bean, their own personal touch.

https://www.larbreacafe.com/blogs/le-blog/guide-pratique-tout-savoir-sur-la-torrefaction-du-cafe-n101

https://perfectdailygrind.com/2020/02/bean-temperature-the-coffee-roasting-curve-and-roast-graph/

Tags: Découverte Torréfacteur Troisième Vague

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