Abstract
Belgian ale flavour consistency depends strongly on fermentation temperature because yeast metabolism controls ester formation, phenolic expression, higher alcohol production, and attenuation behaviour. This study investigates how different fermentation temperature profiles affect flavour consistency in Belgian ale production. Controlled fermentations were conducted using constant, rising, and fluctuating temperature profiles under identical wort composition, yeast strain, pitching rate, and oxygenation conditions. Ethanol formation, attenuation, ester concentration, phenolic compounds, higher alcohols, pH change, yeast viability, and sensory flavour stability were evaluated. The results show that stable moderate temperature profiles produced consistent fruity and spicy flavour balance across batches. Rising profiles improved attenuation but increased higher alcohol formation when temperature elevation was too rapid. Fluctuating profiles caused greater batch variation and inconsistent ester production. The study demonstrates that Belgian ale flavour consistency depends on precise temperature management throughout active fermentation and early maturation rather than relying only on average fermentation temperature.