Yeast recycling and the chemical and sensory quality of cachaça

Why was the work done: Cachaça fermentation often involves recycling the yeast for subsequent fermentations. This practice, common in the brewing and ethanol/biofuel industries, has received little technical attention in the production of cachaça. This work was conducted to address the gap in knowledge and assess the impact of recycling yeast on the quality of cachaça. What are the main findings: Two commercial yeast strains - DistilaMax® RM (‘RM’) and CanaMax® (‘CNX’) - were used. Using sugarcane must, 14 consecutive recycled fermentations were performed. Cachaça (after distillation) was analysed for volatile compounds (GC-MS), ethyl carbamate (GC-FID) and sensorial analysis (Rate All That Apply) with evaluation using PCA. Why is the work important: The sum of volatile compounds (coefficient of congeners) in cachaça produced with the CNX yeast showed greater consistency across all fermentation cycles compared to cachaça made with RM. Yeast CNX demonstrated superior robustness and adaptation to the local climate. However, the sensory quality of cachaça produced with RM was more favourably received by a sensory panel. Fermentation was successful with both yeasts through 14 cycles, producing cachaça that complied with Brazilian legislation. Sensory consistency was maintained up to the seventh cycle, but bacterial contamination was observed from the tenth cycle onwards. Why is the work important: Recycling yeast cells across cachaça fermentations is a reliable technique, ensuring compliance with Brazilian regulations. The study highlights that using selected yeasts with recycling produced a standard final product, and potentially consistent batches of cachaça throughout the annual harvest