The Study Of Pilot Scale Brewing Top-fermented Wheat Beer To Reduce Headache

The top-fermented wheat beer with delicate white foam,richer aroma,higher carbonation,slightly sour mouthfeel,lower bitterness and other excellent characteristics,is very popular around the world.As the fermentation temperature of top-fermented wheat beer is higher(15~25 ?),it leads to fine aroma and headache after drink.So the production scale is not big enough.Therefore,the headache factors(the ratio of higher alcohols to esters and acetaldehyde)in top-fermented wheat beer were researched in this paper.Through pilot-scale brewing equipment(2 KL)and headspace solid-phase microextraction-gas chromatography,the brewing process parameters,including wheat malt proportion,pitching rate,fermentation temperature,fermentation pressure and generation of yeast,were studied to obtain the influence of the ratio of higher alcohols to esters and acetaldehyde in beer.Higher alcohols,esters and acetaldehyde are essential volatile compounds of beer,which decide final flavoring characteristics.Suitable content of higher alcohols,esters and acetaldehyde,and ratio of higher alcohols to esters give beer more coordination and reduce headache after drinking beer.According to form mechanism of higher alcohols,esters,and acetaldehyde and their impact factors,the optimization of the pilot-sale brewing top-fermented wheat beer was carried out,to gain the optimal eratio and acetaldehyde.The volatile flavor compounds of top-fermented wheat beer were simply,rapidly,efficiently and sensitively detected by Headspace solid-phase microextraction-gas chromatography.The conditions as follow: the chromatographic column is DB-WAXETR(30m×0.53×1.0 ?m),the initial temperature is 60?,keeping 2 min;and heating at 6 ?/min to 220?,holding 10 min;the carrier gas is high purity nitrogen;splitless injection;the temperature of injection port is 220 ?,the temperature of FID detector is 250 ?.In this study,11 °P of wheat beer was brewed using the top-fermented beer yeast DM303.The brewing process conditions like wheat malt proportion,pitching rate,fermentation temperature,fermentation pressure and yeast generation,alcohol ester ratio and acetaldehyde content influencing the ratio of higher alcohols to esters and acetaldehyde were explored.Combined with response surface analysis,the optimal process was got: wheat malt ratio is 40%,pitching rate is 0.95×107/ml,fermentation temperature is 17.2 ?,fermenting pressure is 0.12 MPa and best yeast generation is generation of zero.Under this condition,the ratio of higher alcohols to esters was about 1.87.Through comparison of flavor substances in two optimal brewing beer and sensory evaluation analysis,the overall flavor of beer brewed by the latter process is better.However,the optimum brewing condition of top-fermented wheat beer which reduce headache were proposed: wheat malt proportion is 40%,pitching rate is 0.95 ×107/ml,fermentation temperature is 17.2 ?,fermentation pressure is 0.12 MPa and best yeast generation is generation of zero.