Fermentation and distillation of cheese whey: Carbon dioxide-equivalent emissions and water use in the production of whey spirits and white whiskey

Abstract

Whey disposal can be both an environmental and economic challenge for artisanal creameries. Lactose in whey can be fermented to produce ethanol and subsequently distilled. The objective of this study was to use a process-based life cycle analysis to compare carbon dioxide-equivalent (CO2e) emissions and water usage associated with the artisanal or craft production of clear, unaged spirits using whey or malted barley as fermentation substrate. Differences in production were assessed based on key process differences: energy used, water used, distillation by-product disposal, and mass of CO2 produced during fermentation. For this study, whey was assumed removed from the artisanal creamery waste stream. Quantifiable differences were evaluated per 750-mL (45% alcohol by volume) functional unit and expressed as mass-equivalent CO2 emissions (kg of CO2e) and mass of water (kg) used. The CO2e emissions and water usage were quantified using published data, thermodynamic calculations, and mass-balance calculations for a hypothetical distillation system. The process-based life cycle analysis estimated that distillation of fermented whey reduced overall CO2e emissions by 8.4 kg per functional unit and required 0.44 kg less water added into the production process compared with production of a similar clear, unaged spirit using malted barley as substrate. Our preliminary analysis suggests that conversion to distilled whey spirit is a more environmentally responsible approach compared with landfill disposal of whey.