Study On Application Of Wheat In The Brewing Of Light Beer

Recently, the price of barley malt has been raised sharply, because of the shortage of brewing barley in the global. In this paper, wheat was used as the raw material of Light beer brewing instead of some barley malt. It was studied for the whole beer brewing, including wheat variety selection, addition enzymes during mashing, raw material ratio, boiling process and non-biological stability treatment of green beer.Twelve typical wheat varieties grown in diverse locations were studied in this paper. Firstly, some indices, such as pentosan content, protein content and its composition, extract content, buffer capacity and antioxidant activity, which would have significant effects on beer brewing were examined and compared. Furthermore, the proper wheat varieties for beer brewing were selected by fuzzy evaluation method that synthetically evaluate their brewing properties. The results indicated that, the No.6 and No.10 wheat varieties were suitable for beer brewing.Single factor trials was employed to find the important enzymes affecting wort quality indices, which were Bacillus neutral protease, amyloglucosidase and neutral xylanase, respectively. Box-Behnken experimental design was further used to optimize the levels of above three factors. The optimal dosage of enzymes for better wort quality during mashing were as follows, Bacillus neutral protease 300 U/g, amyloglucosidase 29.2 U/g, and neutral xylanase 6 U/g. Verification tests showed that wort viscosity had decreased 25%, wort gain ratio and free amino nitrogen had increased 20% and 70% respectively, compared with control.The influence of wort physico-chemical indices, beer quality and flavor volatilies due to varying raw material ratio was studied. When the proportion of wheat increased from 10% to 30%, the changes of wort and beer quality were insignificant. While it was up to 40%, the contents of free amino nitrogen and total polyphenol were on the low level, and the high molecular weight nitrogen content was remarkably increased. The above results showed that it was appropriate for raw material consist of 40% barley malt, 30% wheat and 30% rice. In order to investigate effects of boiling time, dosage of carrageenan and mashing tannin on high molecular weight nitrogen content of wort, the optimal boiling parameters for lower content of high molecular weight nitrogen of wort were obtained by canonical analysis, namely boiling time was 83.4 min, dosage of carrageenan and mashing tannin were 32.03 mg/L and 52.64 mg/L respectively.In order to investigate processing methods on beer non-biology stability, effects of silica gel, brewing tannin and papain on SASPL value and nitrogen component of beers were studied. It was indicated that, the beer non-biology stability was influenced obviously by silica gel and papain. But the latter had the negative effect on beer foam, which resulted in high content of total acid. Therefore, silica gel was chosen with addition of 300 mg/L. For examining feasibility of technique for production, EBC fermentation test was carried out by using wheat partly substituting barley malt. The result indicated that the quality of wort and final beer made by 30% wheat was as same as the control beer, and the fermentation process was normal. The cost of raw material was decreased by 65 yuan per KL beer.