Abstract
Belgian-style strong ale fermentation requires yeast cultures that can tolerate high sugar and ethanol levels while producing complex fruity, spicy, and alcohol-derived flavour notes. This study evaluates hybrid yeast cultures for Belgian-style strong ale fermentation. Controlled fermentations were conducted using selected hybrid yeast cultures and conventional brewing yeast under identical wort gravity, pitching rate, oxygenation, and temperature conditions. Fermentation rate, attenuation, ethanol yield, yeast viability, ester formation, phenolic expression, higher alcohol production, pH change, and sensory balance were analyzed. The results show that hybrid cultures improved fermentation completion under high-gravity conditions while producing broader ester profiles than standard strains. However, excessive metabolic activity increased higher alcohol formation when temperature was not controlled. Stable flavour development was achieved through balanced culture selection and moderate fermentation temperature. The study demonstrates that hybrid yeast cultures can improve strong ale fermentation performance when yeast tolerance, aroma output, and process control are aligned.