Modulation of beer fermentation time and yeast metabolite generation using audible sound with elevated particle motion.

Studies on the impact of audible sound on yeast growth and metabolism during beer fermentation have focused mainly on the pressure component of sound, with limited attention to particle motion. This study investigated three sound treatments (800-2000 Hz 140 dBRMS re 1 μPa2 @ 1 m, 800-2000 Hz 110 dBRMS re 1 μPa2 @ 1 m, and 4000-10,000 Hz 140 dBRMS re 1 μPa2 @ 1 m) with elevated particle motion, compared to a no-sound control (91 dB), assessing yeast cells in suspension, extracellular metabolites and volatile organic compounds (VOCs). The 800-2000 Hz treatment significantly reduced fermentation time by ∼46 h (p < 0.05), while the 4000-10,000 Hz treatment showed a ∼ 30-h reduction, though not statistically significant (p = 0.08). Both high-intensity treatments retained more yeast in suspension and increased metabolite abundance, with minimal impact on the VOC profile of the final beer. These findings suggest that sound frequency and intensity, particularly particle motion, can influence yeast performance and accelerate fermentation without compromising beer flavor.