This Device Uses Computer Vision to Quantify the Roast Level of Coffee Beans

If something exists, you can be sure that there is someone in the world who is passionate about it. The world practically runs on coffee, so it’s no surprise that there are many people out there who take their hot bean juice very seriously. We’re not just talking about people who have a preference for Robusta beans over Arabica beans, but people who carefully and precisely control every part of the coffee production process. The way beans are ground, the temperature and time used for brewing, and the roast level of the beans all have an effect. That’s why Zach Halvorson created the company Espresso Vision Inc. and developed a relatively low-cost roast level sensor that works using computer vision.

It’s easy enough to purchase a nice burr grinder and to heat your water to the proper temperature for brewing, but not many people are bothering to roast their own coffee beans. But the roast level is probably the biggest factor contributing to the flavor of your coffee. Light roasts are more acidic and actually have higher levels of caffeine, while dark roasts have a more robust, bitter flavor. If you’re roasting your own coffee, which you can do with an electric popcorn popper, it will likely take some trial and error to learn how to reach the roast level you want. This device makes it quick and easy to measure a sample of ground coffee beans to determine their exact level of roast on a scale of 0-35.

There are devices out there designed to do this, but they’re generally geared towards large-scale production and aren’t affordable enough for small coffee shops or individual enthusiasts. Halvorson was able to get the cost of the Roast Vision device down to a fairly reasonable $299. He achieved that by taking advantage of off-the-shelf hardware, most notably SparkFun’s Qwiic-compatible Photodetector Breakout Board based on the MAX30101 optical sensor. When finely-ground coffee beans are placed over the sensor in a little bowl integrated into the 3D-printed enclosure, the device is able to gauge the roast level by examining the color. The results are then displayed on a small OLED screen. If you want to purchase this device, it is currently in stock on the Espresso Vision Inc. website.