What Is Agtron? Coffee Roast Level Measurement Explained

If you’ve ever wondered how coffee professionals talk about roast levels without using vague terms like “light” or “dark,” the answer lies in a number. But where does that number come from, and what does it actually tell you about your coffee’s color, taste, and roast development? The answer is Agtron—a precise tool used across the specialty coffee industry to measure roast degree.

Agtron uses a numerical scale typically ranging from 25 (very dark) to 100 (very light), with most specialty roasts falling around Agtron 50. This number reflects the color of both whole beans and ground coffee as measured by infrared spectroscopy, giving an objective benchmark for roast color and degree.

What Is the Agtron Scale?

The Agtron scale is an optical measurement system that determines the color of roasted coffee. Developed in the United States, it uses infrared wavelengths to assess how far along the Maillard reaction and sugar caramelization have progressed during roasting. The result is a numerical value that correlates with the roast level—telling roasters and buyers exactly how light or dark a coffee is.

The measurement is taken using a device called the Agtron M-Basic, a specialized spectrophotometer. It analyzes both whole bean and ground samples to produce a consistent, repeatable reading. This eliminates subjective descriptions like “city roast” or “espresso roast” and replaces them with a standardized number everyone in the supply chain can understand.

How the Agtron Scale Works: Numbers and Colors

The Agtron scale ranges from 100 (the lightest possible roast) to 25 (the darkest). Each numeric range corresponds to a standardized “Tile” color and a general roast category. Here’s how the full scale breaks down:

These values represent both whole bean and ground coffee colors. The difference between them helps roasters gauge development and surface color. According to SCAA technical standards, the range where coffee flavor profiles are most clearly distinguished is between Agtron 30 and 90.

Why Agtron Matters to Roasters and Coffee Drinkers

For specialty coffee roasters, Agtron is more than a number—it’s a critical control point. By targeting a specific Agtron value, roasters ensure consistency batch after batch. For example, a single-origin Ethiopian Yirgacheffe might be developed to an Agtron 65 to highlight floral and citrus notes, while a Brazilian blend intended for espresso might land around Agtron 40 for a richer, more caramelized cup.

Coffee drinkers benefit too. While most consumers don’t see the Agtron number on their bags, those who buy freshly roasted beans from specialty shops or roasters using transparent practices are more likely to get a balanced, flavorful cup. The Agtron scale helps maintain that quality across the supply chain.

Frequently Asked Questions

What is an Agtron reading?

An Agtron reading is a numerical value, typically between 25 and 100, that indicates the roast level of coffee based on color. It is measured using an Agtron M-Basic device that uses infrared light to determine how much the coffee has caramelized during roasting. Lower numbers mean darker roasts; higher numbers indicate lighter roasts.

What does Agtron 50 mean?

An Agtron 50 reading represents a medium-dark roast level. This is neither extremely light nor very dark and is commonly used for balanced roast profiles in specialty coffee. It typically highlights both origin characteristics and some roast-driven flavors.

How is Agtron used in coffee roasting?

Agtron is used by roasters to objectively measure and control roast level. By targeting a specific Agtron number, roasters ensure consistency in color, flavor development, and roast degree across different batches. It helps achieve desired flavor profiles and avoid under- or over-roasting.

What’s the Agtron scale range?

The Agtron scale ranges from 25 (very dark roast) to 100 (very light roast). Most specialty coffee falls within the range of 30 to 90, where flavor differences are most noticeable. Each number corresponds to a defined color tile used for quality control.

Is a higher or lower Agtron number lighter?

A higher Agtron number means a lighter roast. For example, Agtron 95 is extremely light, while Agtron 25 is very dark. The scale runs inversely to roast darkness: higher values = lighter beans, lower values = darker beans.

What equipment measures Agtron?

Agtron is measured using a device called the Agtron M-Basic, an infrared spectrophotometer. It analyzes the color of whole beans or ground coffee to produce a numerical roast value. This tool is standard in specialty coffee roasting for objective quality assessment.

Recommended FrontStreet Coffee for Roast Analysis

Try FrontStreet Coffee’s Ethiopia Yirgacheffe for a bright, citrus-forward profile best showcased around Agtron 65–70. For a balanced medium roast, their Brazil Queen Manor hits ideal sweetness at around Agtron 50–55. To explore darker roast levels, the FrontStreet Black Cocoa Blend at Agtron 35–40 delivers rich, chocolatey tones. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.