Spectrophotometric Solutions: Utilizing Color Measurement to Optimize Coffee Quality

Spectrophotometers can be invaluable tools in the creation of the perfect cup of coffee. Image Source: Unsplash user Padurariu Alexandru

What makes a good cup of coffee? For some, the lightness, high acidity, and robust caffeine levels of a Nordic roast is the perfect way to start the day. Others prefer a medium roast for its pleasantly complex aroma and delicate mix of body and acidity. Dark roasts let the flavors of the roasting process shine through, offering a full-bodied, smokey-sweet experience with lower caffeine levels that make them perfect for enjoying later in the day. Whatever their preference, today’s consumers are more discriminating than ever when it comes to their coffee, raising the bar for quality amongst both well-established coffee giants and independent up-and-comers just joining this $100 billion worldwide industry.1 Integrating spectrophotometric color measurement throughout the coffee manufacturing process allows you to constantly monitor your product to ensure it conforms to your high standards while minimizing waste and reducing cost.

Color Measurement from Start to Finish

Whatever the final form your coffee will take, excellence starts with the beans. Measuring the color of raw coffee beans ensures that you are starting with the best possible quality ingredients to ensure satisfying roasting results. The color of raw beans varies depending on growing conditions, which affects the taste of the final product, and an inconsistent mix can impede your ability to create blend you are looking for. Spectrophotometric analysis allows you to be sure that the beans you have chosen will respond consistently to roasting.

Once the beans have been selected, the roasting process begins, allowing for each blend to develop the flavor and aroma your customers desire. The heat of roasting removes moisture, breaks starches down to simple sugars that caramelize, alters acidity levels, impacts caffeine content, and leads to the development of caffeol, the oil that gives coffee its distinctive smell.2 The exact aesthetic, aromatic, and taste qualities of the final product will depend on the specific reaction of the raw product to the roasting process. Measuring the color of the beans during roasting gives you optimal control over the final result and spectral analysis of the ground beans ensures that the qualities you are seeking are consistent throughout the blend.

The darkness of a roast can give you important information about its aroma, taste, and caffeine content. Image Source: Unsplash user Bo Smith

Roast Classification

Agtron/SCAA: The Specialty Coffee Association of America has produced eight visual color standards for roast classification of ground coffee. Classification is normally done via visual inspection by comparing the color of a roast to a set of 8 colored disks, each varying 10% in shade and ranging from #95 (“Very Light”) to #25 (“Very Dark”).3 This measurement method depends on the subjectivity of human perception, requires precise sample preparation, and can easily be skewed by factors such as light source and texture, leading to imprecise results.

HCCI: The HunterLab Coffee Color Index measures the spectral reflectance of ground coffee at 640nm, the optimal setting for defining the degree of a roast. To optimize your roasting process, HCCI is best measured during roasting, allowing you to end the process when the coffee reaches its desired color and ensuring batch-to-batch consistency. This sophisticated measuring system does not limit you to matching one of eight pre-set standards, but allows infinite possibilities for creating the perfect roast.

Spectrophotometric analysis of ground coffee allows for thorough measurement of the effect of roasting throughout the bean. Image Source: Unsplash user Felipe Rizo

HunterLab Solutions for Precise Color Measurement

HunterLab’s years of color measurement expertise within the food and beverage industry has led to the development of elegant solutions for analysis of coffee in all its forms. Both the ColorFlex EZ Coffee and D25 NC come complete with firmware to identify the HCCI, SCAA number, and SCAA roast classification, eliminating the subjectivity of the human eye and offering the ultimate in color control.

D25 NC: The D25 NC spectrophotometer offers the most advanced, non-contact color measuring abilities available for large, irregularly shaped samples. By integrating laser-based height measurement, its unique algorithm corrects for texture variation, allowing for seamless measurement of coffee beans in raw, roasted, and ground form without the need for labor-intensive sample preparation. Its automated rotation, ability to measure and average up to five color readings per second, and instant alerts to out-of-spec product combine to produce the ultimate in accuracy at every stage of the coffee manufacturing process. With the ability to store up to 250 product standards, tolerances, scanning parameters, the D25 NC offers unsurpassed versatility and reliability.

ColorFlex EZ Coffee: The ColorFlex EZ Coffee is designed specifically to measure the color of roasted coffee grounds, including freeze-dried grounds and instant powders. Using a 45º/0º optical geometry based on human visual perception, it measures color the way the human eye sees it and provides quantifiable color analysis that ensures lot-to-lot and batch-to-batch consistency. Grounds can be passed or failed based on the the standard of your choosing. With a small footprint, the ColorFlex EZ Coffee is an ideal spectrophotometric instrument for commercial and specialty coffee manufacturers alike.

As demand for high quality coffee continues to grow worldwide, our state-of-the-art technologies allow you to consistently create the best products possible. HunterLab is committed to offering not only the finest spectrophotometric instruments in the world, but also provide the highest level of service and support for your business. Contact us today to learn more about the products we have to offer.