Universal Coffee Color Curve vs. Agtron: Which Will Become the New Industry Standard?

For many years, the Agtron analyzer has been considered the factor standard for measuring the degree of coffee roasting. By measuring the intensity of reflected light on the surface of coffee beans and coffee powder, the analyzer produces a numerical system ranging from 100 (very light roast) to 20 (very dark roast) to indicate the level of roasting. These values are widely used in the roasting industry. 

However, the Agtron values are relatively technical, making it difficult for the average consumer to understand. Moreover, the high cost of the equipment limits its use mainly to medium and large-scale roasters and laboratories. This has led to a demand in the industry for a more universal, intuitive, and cost-effective tool for measuring roast levels. In recent years, the introduction of the “Universal Coffee Color Curve” has offered a promising solution to meet this demand. Can the universal coffee color curve replace Agtron and become the new industry standard? This article explores this possibility.

The Agtron analyzer, with its high measurement accuracy and standardization capabilities, has gradually become a benchmark in the coffee industry. Its numerical range from 100 (very light roast) to 20 (very dark roast) can effectively distinguish between different degrees of roast, providing roasters and industry professionals with precise quality control references.However, Agtron’s values are relatively technical and closed, making it difficult for consumers to intuitively assess the roast level when purchasing coffee. Moreover, the high cost of Agtron makes it inaccessible for many small to medium-sized roasters. In addition, its numerical system only indicates roast depth and cannot describe the dynamic changes in color throughout the roasting process. This limitation has created a demand for a tool that can provide a more comprehensive and standardized description of roasting colors.

To address the limitations of the Agtron analyzer, the UC Davis Coffee Center introduced the concept of the “Universal Coffee Color Curve.” This curve is based on the internationally recognized CIE Lab* color space standard (Lab*) and uses a three-dimensional color coordinate system to comprehensively quantify the color changes of coffee beans throughout the roasting process.

Through the analysis of tens of thousands of data points, the research found that different roasting curves and bean types follow a similar color change pattern along a single curve. This universal curve reveals the dynamic changes in color from green beans to darkly roasted beans, covering a broad range of coffee varieties and roasting methods. This research offers a more scientific, universal, and intuitive tool for describing coffee roasting levels.

• More Intuitive Color Descriptions:
  The universal coffee color curve, based on the three-dimensional Lab* color coordinates, can provide a richer and more comprehensive description of coffee colors compared to a single Agtron value. Consumers can easily understand the roast level through visual color descriptions such as “light yellow-brown” or “deep red-brown,” instead of just seeing a set of numbers.
• High Applicability:
  Measurements for the universal color curve can be taken using any device capable of measuring Lab* values, such as colorimeters or spectrophotometers, which lowers the technical barrier and makes the curve more accessible for widespread adoption.
• Accurate Tracking of Roast Changes:
  The universal coffee color curve not only describes the final roast level of the coffee beans but also records the dynamic trajectory of color changes throughout the roasting process. This is valuable for analyzing roasting curves and adjusting flavor profiles
• Standardization and Consistency:
  Because the CIELAB color space is widely used internationally and maintains strong consistency across different devices, lighting conditions, and operational environments, the data from the universal coffee color curve offers a high degree of standardization and reliability.

Although RoastSee C1 is also a device used for measuring the color of roasted coffee, its primary function is based on measuring Agtron values. As LeBrew’s coffee color analyzer, RoastSee C1 can accurately measure the Agtron values of coffee beans, helping roasters efficiently manage quality within the existing Agtron system. In contrast, the universal coffee color curve focuses more on providing a comprehensive color description system from the Lab* color space, offering a broader and more universally applicable standard for roast level evaluation.

This means that RoastSee C1 is more suitable for roasters who are already relying on the Agtron standard, while the universal coffee color curve has the potential to become a new standard across the industry, providing a more holistic solution.

Although the universal coffee color curve shows significant advantages in describing the color changes of roasted coffee, completely replacing Agtron will require time and greater market acceptance.

Firstly, the Agtron system has been widely used in the industry and is recognized by the SCA (Specialty Coffee Association) as a reference standard. If the universal coffee color curve is to be promoted, the industry will need a transition period to adapt to the conversion between Lab* coordinates and existing Agtron values.

Secondly, the universal coffee color curve is still in the early stages of commercial promotion and validation. Although it has demonstrated high consistency in scientific research, its effectiveness in actual production environments needs further empirical support.

Finally, consumer education is a crucial component. Although the universal coffee color curve offers a more intuitive description method, promoting a new color standard requires time and a clear promotional strategy. Without a unified market education approach, it may be difficult for the new standard to replace Agtron in the short term.

The introduction of the universal coffee color curve has provided the coffee industry with a more scientific and standardized roasting evaluation system. It not only accurately describes the color changes throughout the roasting process but also serves as a bridge for better communication between the industry and consumers. In the future, if the universal coffee color curve can be further validated in commercial applications and gain recognition from major global coffee associations and roasters, it could gradually become the new industry standard, and even replace Agtron in certain areas.

Ultimately, we hope that in the future coffee market, consumers can make more informed choices about the roast level of coffee beans based on the universal coffee color curve descriptions, selecting products that match their taste preferences. For industry professionals, this system could offer a more standardized quality management tool, laying a solid foundation for the further development of the global coffee industry.

[1] National Coffee Association, 2023 National Coffee Data Trends Study.

[2] Scott C. Frost, William D. Ristenpart, Jean-Xavier Guinard, "Effects of Brew Strength, Brew Yield, and Roast on the Sensory Quality of Drip Brewed Coffee," Journal of Food Science (July 2020)

[3] Common terms for some of these different roast profiles include “fast start,” “slow start,” “negative rate-of-rise,” “exaggerated flick,” and several others.