Difference between light, medium and dark roast?

Three roast families are defined by drop temperature and stop timing: light (Cinnamon/City, 205-215 °C, just after first crack), medium (City+/Full City, 215-224 °C, end of development), and dark (French/Italian, 225-245 °C, during or past second crack). Each foregrounds a different register — fruity-bright, balanced-sweet, bitter-chocolaty — and suits a different brewing method.

A light roast ends early in development, typically 60 to 120 seconds past first crack, at a bean temperature of 205-215 °C. The bean stays dry on the surface (no visible oil), takes on a pale hazel colour, and shows an Agtron (SCA-standard colour index) reading between 80 and 95 on whole beans. Origin acidity — citric, malic, phosphoric — and perceived sweetness are preserved while roast aromatics remain in the background. This is the Scandinavian signature (Tim Wendelboe, La Cabra) and the modern specialty default, tuned for V60, Chemex, Aeropress and cupping sessions.

A medium roast (City+ to Full City) extends development by 2-3 minutes past first crack, reaching 215-224 °C. The bean turns chocolate-brown with no visible oil, Agtron 65-80. The most volatile acids mellow, sweetness peaks through caramelisation, and melanoidins produce cocoa, roasted hazelnut and soft caramel notes. This is the historical home of early-2000s US Third Wave roasters (Counter Culture, Intelligentsia, Stumptown) and the easiest bridge for drinkers moving from supermarket blends to specialty. Home moka pots and many contemporary espressos sit here.

A dark roast enters second crack or goes beyond, bean temp 225-245 °C, Agtron 35-60. Oils migrate to the surface, sugars finish caramelising then partially carbonise, caffeine stays almost stable but acidity collapses. The sub-names include French Roast (late second crack), Italian Roast (past it) or Spanish/Viennese depending on local tradition. The profile reads dark chocolate, smoky, liquorice, with heavier bitterness and thicker body — the turf of Neapolitan espresso, Turkish coffee and many industrial supermarket blends. A technical footnote: past 240 °C, you lose an extra 15 to 20 % of dry mass compared with a light roast (overall shrinkage rises from 14-17 % to 20-22 %). In Belgium, daily filter tradition leans historically toward medium to medium-dark, while the specialty wave in Brussels, Ghent and Antwerp pushes menus toward light-to-medium profiles.

Snapshot comparison across the three degrees

Navigating the Spectrum

The light-medium-dark roast classification is the most commonly used consumer vocabulary in coffee, but it conceals enormous variation behind apparently simple terms. In the specialty coffee industry, "light roast" describes a coffee dropped from the drum shortly after first crack, before significant second crack activity, at a bean temperature roughly in the range of 195-205 °C — though this varies by roaster and machine. In a supermarket context, the same term might describe a roast that would be considered medium or even medium-dark by specialty standards, because commercial dark roasts are the baseline from which the lighter end of a commercial range is calibrated. This definitional slippage means that the "light roast" label on two different bags of coffee can refer to products with dramatically different roast levels, chemical profiles, and cup characteristics.

The chemical transitions that define the spectrum are real and consequential. Moving from light to medium roast means more complete development of the Maillard products responsible for complexity, more caramelisation, less chlorogenic acid, and the beginning of body-forming melanoidin development — the cup gains sweetness and body while typically retaining significant origin character. The transition from medium to dark roast accelerates all these processes and begins the degradation of the volatile aromatic compounds that distinguish one origin from another — the cup gains smokiness, carbon notes, and uniform bitterness as individual character is replaced by roast-derived character. This is why experienced tasters often say that all dark roasts start to taste similar while light roasts from different origins can be dramatically different from each other: the roast is progressively erasing rather than building differentiation.

Practical Recommendations

When buying coffee and navigating roast level descriptions, the most useful practical approach is to ask for or look for the roast date alongside the roast descriptor. A bag labelled "light roast" with no date information is less useful than one that says "light roast, roasted three days ago" — the freshness context matters enormously to what you will actually experience in the cup. As a home brewer, consider that different roast levels respond differently to your parameters: light roasts generally benefit from higher water temperatures (93-96 °C) to fully develop their acid structure; dark roasts are better extracted at lower temperatures (88-92 °C) to avoid amplifying bitterness. If you are new to specialty coffee and find very light roasts challenging, a medium roast from a quality origin is an excellent bridge — it offers more complexity than a commercial dark while being more approachable than an aggressively light specialty pour-over.