Impact of Early Detection of Sour Coffee Beans
by Francesco Dell’Endice, PhD - CEO and Founder of QualySense
Sourness is a common taste sensation that can be found in both coffee and wine. In wine, sourness is typically associated with high levels of acidity, which can come from a variety of factors such as the grape variety, climate, and winemaking techniques. Similarly, in coffee, sourness is often caused by high levels of organic acids, such as citric acid, which can be influenced by factors such as the coffee variety, growing conditions, and processing methods. Just as a highly acidic wine can be perceived as sour and unbalanced, a highly acidic coffee can also be unpleasant to drink and negatively impact the overall flavour profile.
Sour beans are associated with an increased concentration of organic acids such as citric, malic, and tartaric acids, which can lead to a sour taste that is negatively correlated with overall coffee quality. According to a study by researchers at the University of Hawaii, coffee samples with a higher concentration of citric acid were perceived to be sour by taste testers (Schenker et al., 2014). Additionally, a study published in the Journal of Food Science found that sourness is negatively correlated with overall coffee quality, indicating that sour beans can negatively impact the flavor profile of the coffee (Mehmood et al., 2020). Another study published in the Journal of Sensory Studies found that a sour taste was the most common off-flavour detected in low-quality coffee samples. The study tested coffee samples from various regions and found that sourness was a common characteristic of low-quality coffee, along with bitterness and astringency (López-Galilea et al., 2015). Therefore, sour beans can also affect the aroma and acidity of the coffee, leading to an inconsistent and unpleasant drinking experience.
Detecting sour beans early in the production process is therefore essential for ensuring consistency, customer satisfaction, and cost savings as they can have a detrimental impact on the taste, aroma, and acidity of the coffee, just as monitoring acidity levels is important for producing high-quality wine. Eliminating sour coffee beans leads to a more consistent and enjoyable drinking experience for consumers.
Sour coffee beans contain chemical compounds that absorb light in the near infrared (NIR) region, which is not visible to the human eye. Near infrared spectroscopy is a non-destructive analytical technique that can measure the amount of light absorbed by these chemical compounds in the beans, providing information about their chemical composition. On the other hand, visual analysis relies on the human eye's ability to detect differences in color, size, shape, and texture of the beans. While sour coffee beans may exhibit some visual changes, these changes can be subtle and difficult to detect, especially for untrained individuals. Therefore, near infrared spectroscopy is a more reliable and objective method for detecting sour coffee beans compared to visual analysis. It can provide accurate and quantitative information about the chemical composition of the beans, allowing for precise identification of sourness and other defects.
For more info contact Francesco Dell’Endice at qualysense@ferrum.net.
QSorter is the only high-speed single bean inspection technology that is able to detect sour beans reliably. Learn more about this and all its features for green coffee inspection here: LINK
