Behind the Scenes · The Coffee Journal
Artisanal Roasting
How green bean becomes coffee. Between 200 and 230 degrees, the green bean transforms. In a few minutes, complex chemical reactions create the hundreds of aromas that make up the coffee you drink every morning.
Alchemy
The magic of heat
Roasting is one of the most complex food transformations. A bean that smells of grass and earth becomes, in a few minutes, an aromatically extraordinary beverage.
From Green Bean to Cup
The green bean contains aromatic precursors in the form of sugars, amino acids, and organic acids. Heat triggers chemical reactions: sugar caramelization, the Maillard reaction between sugars and proteins, and thermal degradation of acids. These three simultaneous processes create the 800 to 1000 aromatic compounds of roasted coffee.
It is the roaster's art to master these reactions: too fast, and the coffee burns on the surface before being developed inside. Too slow, and the aromas evaporate without forming. Balance is a matter of degrees and seconds.
Reactions
The chemistry of coffee
Three major chemical reactions occur simultaneously during roasting. Each contributes to the final profile in a different way.
Color and Complexity
Reducing sugars react with amino acids to create hundreds of complex aromatic molecules. This reaction gives coffee its golden-brown color and its toasted bread, hazelnut, and caramel aromas.
Sweetness and Depth
Sugars degrade under the effect of heat to form caramelized molecules responsible for sweetness and dark color. Longer roasting accentuates these caramelized notes at the expense of fruity acidity.
Acidity that Balances
The organic acids present in the green bean (chlorogenic acid, citric acid, malic acid) gradually degrade with heat. Short roasting preserves the bean's fruity acidity. Long roasting attenuates it and reveals body and bitterness.
Levels
From light to dark
Roasting levels define the fundamental character of a coffee. From light roast, which preserves fruity freshness, to dark roast, which reveals power and body.
Light Roast
The bean stops just after the first crack. The floral and fruity aromas of the origin are preserved. Acidity is lively, body is light. The preferred roast for specialty coffees and filter.
Medium Roast
Between the two cracks. The perfect balance: fruity acidity has integrated, body has developed, notes of caramel and hazelnut emerge. The roast for specialty espresso and Carrera Café.
Machines
The master's tool
The artisan roaster works with precise machines that allow control of every parameter of the roasting curve.
The Rotating Drum
The reference machine for artisanal roasting. The beans rotate in a heated drum, ensuring uniform exposure to heat. The roaster controls the heat source (gas, electricity), drum speed, and airflow through a precise digital interface. Each batch is recorded on a real-time temperature profile.
The Artisan
Human expertise
The machine doesn't do everything. The roaster interprets data, adjusts the profile in real time, and makes choices that no algorithm can anticipate. It is an art in itself.
The Ear and the Nose
An experienced roaster works as much with their instruments as with their senses. The first crack sounds like popping corn. The scent evolves from grass to hazelnut to burn. The color of the bean provides valuable visual clues.
It is this dialogue between digital data and sensory perceptions that defines the artisan. Each different batch of coffee requires subtle profile adaptation. It is a learning process that never ends.
Our Story
Géogène's roasting process
At Carrera Café, we trust Géogène, an artisanal Quebec roaster, to transform the selected green beans into exceptional coffees that we serve you in Petit-Champlain.
Géogène · Specialty Roaster
Géogène roasts our coffees in small batches in Quebec City, precisely controlling every roasting parameter. Their artisanal approach guarantees maximum freshness and exceptionally precise aromatic profiles. We receive our batches a few days after roasting, never more.
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