Impact of Fusarium culmorum-infected barley malt grains on brewing and beer quality

Fusarium culmorum infected malt is capable of entering into the brewing supply chain and have a major impact on the processability and quality of beer if present at high initial loads. In this study, in vitro F. culmorum infected malt was used to produce lager beer. It was found that the wort containing infected malt had a lower pH, a higher FAN, higher β-glucan and a 45% increase in the purging rate than the control. It caused premature yeast flocculation, although final extract and attenuation degree were not affected. The beer produced with infected malt (IB) had a considerably different amino acid profile, compared to control beer (CB), while sugar and organic acid profiles were comparable. The flavor characterization of IB revealed a higher concentration of esters, fusel alcohols, fatty acids, ketones, and dimethylsufide. Acetaldehyde was particularly higher for the IB when compared to the CB (98 mg/L and 7 mg/L, respectively). Another notable difference of IB was the greater proportion of Strecker aldehydes and Maillard products contributing to an increased beer staling character. IB had a 67% darker color with a trend to higher foam stability. It was found that 78% of the accumulated mycotoxin deoxynivalenol in the malt was transferred into beer.