Abstract
Top-fermented beer production relies on efficient sugar utilization by ale yeast, which directly affects attenuation, ethanol yield, fermentation time, residual sweetness, and flavour development. This study examines sugar utilization patterns during top-fermented beer production. Controlled ale fermentations were performed using standardized wort composition, pitching rate, oxygenation, and fermentation temperature. Glucose, fructose, sucrose, maltose, maltotriose, ethanol, glycerol, yeast cell density, attenuation, pH, and aroma by-products were monitored across fermentation stages. The results show that simple sugars were consumed rapidly during early fermentation, while maltose became the dominant carbon source during active fermentation. Maltotriose utilization occurred more slowly and strongly influenced final attenuation. Incomplete maltotriose consumption increased residual extract and body but lowered ethanol yield. Yeast vitality and nutrient availability improved late-stage sugar uptake. The study shows that top-fermented beer quality depends on balancing sugar availability, yeast adaptation, and fermentation duration to achieve the intended alcohol and flavour profile.