Low-cost fluorescence-based method for beer bitterness measurement

Abstract

Abstract A simple low-cost methodology for assessing beer bitterness using the IBU (International Bitterness Units) scale has been developed. The experimental setup is composed of a UV source, a fluorescent material and a digital single-lens reflex camera. The main concept of the method involves estimating the UV attenuation through IBU solution samples, by comparing the resulting fluorescence instead of the direct UV data obtained with a spectrophotometer. This significantly lowers the cost of the IBU measurement, allowing the hop bitterness values to be directly obtained from simple processing of the fluorescence images. For validation purposes, all values were compared to traditional measurements made with a spectrophotometer. A calibration procedure was carried out using samples with different iso-alpha-acid concentrations, which were naturally measured with the traditional IBU methodology. Finally, for illustrating the application of the novel method, commercial beers were analyzed using the traditional approach and compared with the proposed methodology. The results yielded a root mean square error of predicted samples below 3 IBUs, which demonstrates the potential of the proposed alternative.