Study On The Process Of Hazy IPA Beer

In this paper,three kinds of yeasts,Londonale III,S-33 and K-97,were selected for brewing.The physical and chemical indexes,hypoglycemic rate,alcohol production capacity,diacetyl reduction rate and flavor substances of mature and Hazy IPA were detected.The taste and flavor of Hazy IPA produced by these three yeasts were comprehensively evaluated by sensory evaluation,and the yeast suitable for producing Hazy IPA was screened.Although the proportion of hops used in beer brewing is small,the flavor substances in hops are rich,which has a significant impact on the quality and flavor of beer.Polyphenols in hops can appropriately prolong the storage time of beer and enhance the flavor stability of beer.More than 400 volatile components in hops have been identified,including hydrocarbons,aldehydes and ketones,sulfur compounds,acetals,furans,epoxides,etc.Most of the terpenes detected have strong hydrophobicity and are easy to volatilize when boiling at high temperature.A small part of terpenes can be retained in wort and wine body,which has little effect on flavor,such as ?-geranione,?-humulene,etc.;terpenoids in hops have strong hydrophilicity and are easy to be retained in the cooled liquor body,such as linalool,geraniol,?-citronellol and ?-terpenes Alcohol has a great influence on beer flavor.In the process of beer fermentation,dry adding a variety of hops can make the flavor of beer more hierarchical.Different aroma components of hops cooperate and overlap with each other.From the perspective of the combination of essential oils of different hops,flavor complementation,inhibition,enhancement and reduction will be produced.Dry hopping play an important role in the brewing of Hazy IPA.Most of the hops used in Hazy IPA are hop varieties with prominent fruit flavor,especially those with citrus flavor and tropical fruit flavor.The commonly used varieties are: Citra,Amarillo,Simco,Mosaic,Galaxy,EI Dorado,Century,Cascade Columbus,etc.In order to explore the best varieties and quantity of hops,headspace solid-phase microextraction(HS-SPME)was used to extract hops aroma.Gas chromatography-mass spectrometry(GC-MS)and gas chromatography olfactory measurement(GC-O)were used to analyze and identify the flavoring substances in different combinations of hops,and to explore the interaction and transformation of hops flavor substances in the fermentation process.The results showed that there were 55 main components in hops,including 22 terpenes,mainly isocaryophyllene,?-caryophyllene and ?-humulene.The important aroma components in hops were geraniol,linalool,isocaryophyllene and ?-caryophyllene.During the fermentation process,linalool was converted into ?-terpineol,geraniol was converted to ?-citronellol,?-citronellol was converted to Citronellyl acetate.There was a synergistic effect between geraniol,?-citronellol and linalool,and the fruit flavor of beer was more significant when the three existed in a reasonable range.Finally,it was concluded that Comet,Mosaic and Simcoe had the best taste when they were dried at the ratio of 5:3:2.During the brewing process,the number of yeast,hypoglycemic,alcohol content and diacetyl change were detected.The results showed that: londonale III yeast had fast proliferation rate and good reproductive performance,which was more conducive to beer fermentation.The fermentation speed of londonale III and k-97 was faster,but the residual sugar content of k-97 was less,which could not bring mellow and full taste to beer.The results showed that London III yeast had high flocculation degree,fast yeast sedimentation rate and fermentation degree of 73%,but malt and residual sweetness were relatively obvious.The three kinds of yeasts have the same brewing technology in the brewing process,and the indexes of wort are stable,and the reliability of the detected data is good.There is a certain gap between the three kinds of yeasts in reducing sugar rate,alcohol content and fermentation degree,but the overall fermentation performance is good.The overall physical and chemical indexes and sensory evaluation of cloudy IPA beer brewed by London III yeast are higher.Based on the varieties of dry hops determined by experiments,the turbidity IPA was optimized by response surface analysis method through single factor test.The main raw materials were malt,oatmeal,wheat and hops.Londonale III yeast was used for brewing.In the fermentation process,hops were put into dry to produce IPA with high turbidity.Finally,the optimal process parameters were obtained as fermentation temperature The results showed that the average sensory score of beer was 91.5,the color of finished beer was 12 EBC,turbidity was 513.4EBC,alcohol content was 5.4%vol,total acid content was 1.6ml · 100ml-1,The color is amber,the wine is turbid,highlighting the rich tropical fruit flavor,especially mango,grapefruit,watermelon characteristics,and the bitterness is generally convergence,easy to import,full-bodied wine.