Define a coffee colour profile:

The colour of coffee is much more than just an aesthetic feature. It is a decisive quality factor that provides information about the degree of roasting, aroma, consistency and ultimately the taste. But how can the colour of coffee beans be determined objectively? This is where spectrophotometric colour measurement devices come into play.

Why the colour of coffee is so important

Coffee roasters, quality managers and laboratories face the daily challenge of producing a consistent product. Even small deviations in the roasting process can change the colour of the beans and thus the entire sensory perception.

• Colour = indicator for degree of roast: from light, acidic roasts to dark, strong varieties.

• Objective quality control: Consumers expect consistent colour and taste.

• Efficiency in production: colour measurement saves time and reduces waste.

Limits of visual assessment

Human perception is subjective and is influenced by lighting conditions, fatigue or individual differences. This is why more and more companies are turning to instrumental colour measurement to achieve reproducible and standardized results.

SCAA vs. HCCI – Standards for coffee colour

Different scales are established in the coffee industry:

• SCAA-Agtron scale: traditionally used to visually classify degrees of roasting.
• HCCI (Hunter Coffee Color Index): a modern index based on spectral colour measurement. It provides objective and precise results and enables better comparability between roasting plants.

The HCCI offers the advantage that it can be calculated directly from the measured values of a spectrophotometer such as the Aeros or the ColorFlex L2 and thus enables a consistent, standardized evaluation. The SCAA’s roasted coffee set, on the other hand, is a purely visual coarse scale that is suitable for evaluating coffee, but is prone to error due to the subjectivity of the evaluation and only offers eight shades.

The roast coffee set provided by the SCAA (Specialty Coffee Association of America) with a standard colour range of 95 (light) to 25 (dark).

How spectrophotometers measure coffee colour

HunterLab spectrophotometers – like the ColorFlex L2 or the non-contact Aeros – analyze the reflected light components of the coffee beans. This produces an exact measured value in the CIE L*a*b* colour space, from which indices such as the HCCI can be calculated.

• L* = Lightness (from very light to very dark roasts)
• a* = red-green component
• b* = blue-yellow component

This precise analysis ensures that each roast batch achieves the desired colour and quality.

Advantages for roasters and producers

• Constant quality assurance: independent of subjective perception

• Time saving: quick analysis without lengthy sensory panels

• Reduction of waste and costs

• Transparency for audits and certifications

Conclusion: Objective colour measurement as a success factor

The future of coffee production lies in the combination of the artisanal art of roasting and precise, instrumental analysis. Whether using indices such as the HCCI or the SCAA, as well as color values such as L*,a*,b*, manufacturers ensure that every cup of coffee not only tastes the same, but also carries the familiar color.

These spectrophotometers determine colour and degree of roasting accurately and reliably:

❓ How is the colour of coffee beans measured?

The best way to measure the colour of coffee beans is with the Aeros spectrophotometer. The coffee beans are positioned in a sample tray underneath the sensor and precise measurement results are shown on the display in just a few seconds at the touch of a button.

❓ What is the HCCI (Hunter Coffee Color Index)?

The HunterLab Coffee Color Index – HCCI – is a color indicator based on spectral color measurement. It provides reproducible, objective results and is ideal for quality control in coffee roasting. The HCCI measures the reflection of ground coffee at 640 nm, which is ideal for determining the degree of roasting. The HCCI correlates well with the SCAA visual roasting standards and has a range of 20 units.

❓ How does the SCAA scale differ from the HCCI?

The SCAA-Agtron scale is a visual reference for roasting degrees, while the HCCI is based on objective measurement technology. The HCCI therefore enables more precise and standardized comparability.

❓ Why is a visual assessment not enough?

Human perception is subjective and strongly dependent on light, experience and fatigue. Instrumental color measurement, on the other hand, offers constant and reproducible results.

❓ What are the advantages of spectrophotometers for coffee roasters?

• Constant quality assurance independent of subjective, human perception

• Faster processes in the laboratory and production

• Fewer rejects and material losses

• Documented values for audits and certifications

❓ Which HunterLab devices are suitable for the colour measurement of coffee?

Depending on the requirements and laboratory or production environment, our application experts will advise you individually which device is the best choice for the respective sample. In most cases, the Aeros is suitable for the color measurement of coffee beans/coffee powder, while the ColorFlex L2 is also a suitable choice for coffee powder/ground coffee. Ultimately, it depends on the sample handling, which accessories can be used and what the conditions are like in the respective environment. Contact us here, the colorimetry experts at HunterLab will be happy to advise you!