What is an Agtron score?

Agtron is a near-infrared colour scale used to measure roast degree objectively. On the commercial scale, higher numbers mean a lighter roast and lower numbers mean a darker roast, so a 70 is light and a 30 is very dark.

What are first crack and second crack?

They are audible cracking sounds as beans roast. First crack, around 196 °C, is moisture escaping and marks the start of drinkable light roasts. Second crack, around 224 °C, is the bean structure fracturing and signals dark, oily roasts.

Does a darker roast have more caffeine?

Not meaningfully by mass. Roasting changes flavour far more than caffeine, and the differences between light and dark are small. By weight they are nearly identical, though scooped by volume light roasts are slightly denser and can measure a touch higher.

Why do dark roasts look oily?

As beans roast into second crack, oils migrate from the interior to the surface, giving dark roasts their characteristic sheen. Lighter roasts stay dry because they are dropped before those oils reach the surface.

Is this lookup done in my browser?

Yes. The roast data and the Agtron-to-roast matching run entirely in your browser as a static reference. Nothing is fetched, uploaded or stored, so it works offline.

Coffee Roast Level Reference

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Match a roast level to the cup you want

How long coffee is roasted shapes almost everything you taste — acidity, sweetness, body and how much of the bean’s origin survives. This reference maps the roast spectrum from light to espresso with Agtron colour scores, drop temperatures, crack milestones and flavour notes, and lets you look up any commercial Agtron number.

How it works

Roasters track colour with the Agtron scale, where higher numbers are lighter. As beans heat they pass two milestones:

First crack   ~196 °C / 385 °F   light roasts drop here or just after
Second crack  ~224 °C / 435 °F   dark, oily roasts develop here

The further past first crack a roaster drops the beans, the more roast-driven flavour (chocolate, smoke, char) develops and the more origin acidity and fruit fades. The lookup takes an Agtron score and returns the matching roast band and its flavour profile; values outside the typical range snap to the nearest extreme as guidance.

Tips and notes

Light roasts preserve the most origin character — bright acidity, florals and fruit — but need careful brewing to avoid sourness.
A dry, matte surface means the roast was dropped before second crack; surface oil means it went into a dark roast.
“Espresso roast” is a style, not a rule — you can pull espresso from any roast level, though darker roasts are more forgiving.
Roast labels like “City” or “Full City” are unstandardised; the Agtron number is the more reliable comparison across roasters.