Beer Bitterness Measurement Using Mach-Zehnder Interferometer

Abstract

This article introduces an innovative optical fiber sensor designed for the assessment of beer bitterness. The sensor utilizes a Mach-Zehnder interferometer (MZI) incorporating two long-period fiber gratings (LPFGs). Leveraging the sensitivity of the LPFGs to the refractive index of the surrounding medium, the sensor detects variations corresponding to the concentration of iso- $\alpha$ -acids responsible for the bitterness in beer. Employing a two-point on-line self-calibrating procedure, the sensor estimates the bitterness of unknown samples by comparing them with reference samples of known bitterness.