Roasting is the stage where the green coffee bean transforms into what we recognize in our cup. It is a complex chemical reaction — a combination of caramelization, Maillard reaction, and pyrolysis — that develops the hundreds of aromatic compounds that define a coffee's profile. And the final color of the bean after roasting, from golden beige to almost black brown, fundamentally changes what we will taste.

Many people think that the darker the coffee, the stronger it is. This is a misleading simplification. The truth is more nuanced, and understanding it can radically change the way you choose your coffee.

Light roasting: when fruit and flower express themselves

A light roast stops the heating fairly early in the process — usually after what is called the "first crack," the moment when the beans crack open under the pressure of internal gases. The result is a cinnamon-colored bean, light and dense. This is the preferred profile of specialty coffee lovers who want to taste the terroir of a single-origin bean.

Light coffees have more acidity, aromatic complexity, and better preserve the characteristics of the country of origin. A lightly roasted Ethiopian will express floral notes, bergamot, and red fruits. A Kenyan will show its citrus and liveliness. It is in light roasting that coffee most faithfully reveals its identity.

Medium roasting: balance is king

Medium roast is the most versatile. It retains some of the original characteristics while developing a rounder body and notes of caramel, hazelnut, and milk chocolate. Acidity is present but balanced by sweetness.

This is the profile that satisfies the most people. It works well as espresso or filter, with or without milk. For a morning coffee that is accessible, round, and full of character without being aggressive, balance is key.

Dark roasting: body and smokiness

A dark roast pushes the bean further, sometimes to a second crack. At this stage, oils rise to the surface of the bean, which becomes shiny and dark. The original characteristics have largely disappeared, replaced by roasting notes themselves: smoke, bitter cocoa, burnt caramel, licorice.

Dark coffee has more body, less acidity, and a more pronounced bitterness. This is the profile often associated with traditional Italian espressos and commercial coffees. It works very well with milk, as its intensity cuts through foams and creams.

Caffeine and common misconceptions

A very common myth: dark coffee contains more caffeine. This is incorrect. In reality, caffeine is thermostable and does not significantly degrade during roasting. The difference in caffeine between a light and a dark coffee is marginal. What really changes is the taste, body, and aromatic complexity.

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