Studies On Malting Processing And Brewing Characteristic Of Black Malt

Black malt was necessary and important for the brewers to produce various types of beer.The final beer could be provided the characteristic color, flavor and taste. It was studied thatthe processing technique, flavor and quality evaluation of black malt and its effect on finalblack beer quality in this thesis. It was optimized the process of malting and kilning for theblack malt, the characteristic flavor compounds of black malt was determined and the formingpathway of the flavor compounds was discussed, the evaluation system of black malt qualitywas established primarily, and the effect of using black malt in the brewing on the beer flavorstability was discussed. The main results were as follows:1. The effect of steeping degree, germination temperature, germination time and kilningtemperature on the color, extract yield and sensor evaluation of black malt was determinedby crossing experiment. The optimal processing of black malt was steeping degree with48%, germination on 17℃ for 4 days and kilning temperature with 85℃. The color of thefinal black malt was 850 EBC, extract yield was 71% and the sensor score was 7.0. Thetaste of black extraction was better with strong sweetness and light bitterness while thekilning temperature was 240℃, and was extracted on 75 for 28 minutes.2. The main flavor compound of black malt was formed by Millard reaction. The volatilecompounds such as aldehyde, furan, pyrazine, and pyrrole which was formed on hightemperature was the main composition of the black malt aroma. The content of aldehydeand pyrazine of black malt was much higher than that of light malt. On the other hand,many flavor compounds could be formed by degradation of enzyme and chemicaloxidation of non-saturated fatty acid. It could also be formed by the degradation of somecompounds by heat, such as DMS.3. The evaluation system of black malt quality was recommended. The quality of black maltcould be evaluated by the common analysis index, the content of characteristic flavorcompounds and sensor evaluation. The quality of black malt could be discussed accordingto three-part of the evaluation system. The sensor evaluation of black malt was veryimportant for the final beer.4. There was not only some compound with characteristic aroma in the black malt, but also alarge amount of aldehyde which was associated with beer staling flavor. It was concernedabout the amount of black malt with suitable level used in the black beer brewing. Thefinal black beer was brewed successfully with the color of 150 EBC and obviousapparence by changing the raw material and its proparation. The aroma of black beer wasvery strong and pure. The content of higher alcohol and ester in the black beer was verysimilar with the content in light beer. Although the content of staling compound was muchhigher, the beer flavor stability was better with the recovering of the strong sweet maltaroma. Darker the beer color was, longer the beer flavor stability was.