Ice Wine Yeast Screening And Production Process Optimization

The history of ice wine fermentation has been over200years, and its brewingtechnology is very fine and exquisite. In this paper, the Meili snow mountain CabernetSauvignon ice grape was taken as raw material, the effects of different conditions onfermentation rate and wine quality, different types yeast, different ways of addition ofnutrition, different fermentation temperature and stirring times on fermentation rateand wine quality, were analyzed. According to the physic-chemical index of sugar,acid, alcohol and the sensory evaluation after the fermentation, the optimumparameters were established.The effects of different types yeast and different ways of addition of nutrition onthe speed of fermentation and ice wine quality were analyzed. When R2yeast added,the fermentation gained the highest rate. The wine fermented by K1yeast had thehighest quality with highest total acid and the lowest volatile acid. Once some kind ofyeast was added, there was no difference about fermentation rate between the groups,nutrition added in different phase and at the beginning or1/3of the fermentation, butboth faster than the group without nutrition added. And its influence on ice winequality was: no nutrition added> added when ferment to1/3> added at the start ofthe fermentation. Based on the comprehensive consideration, the optimum way ofaddition of nutrition is the one that nutrition added when it fermented to1/3.The effects of different types yeast and different fermentation temperature on thespeed of fermentation and ice wine quality were analyzed. It still had the fastestfermentation rate with the R2yeast at different fermentation temperature. The winefermented by K1yeast had the highest quality with highest total acid and the lowestvolatile acid. The higher fermentation temperature was, the faster fermentation rate itgained. The ice wine quality at different temperature was:10℃＞12℃＞15℃＞18℃.When the fermentation temperature increased to higher than12℃, the concentrationof volatile acid would increase sharply. And12℃is selected as the optimumtemperature based on an overall consideration of various factors.This paper studied the influence of different stirring times and the different kinds ofyeast on the speed of fermentation and ice wine quality. Results showed that atdifferent stirring conditions it had the highest rate using the R2yeast. Still, whenfermented using the K1yeast, it got the highest quality wine. Stirring times had little effect on total acid and volatile acid, but had significant influence on pigmentdigestion. The more stirring times, the deeper the wine color. Along with the stirringtimes increased, the fermentation speed increased accordingly. And the difference wasremarkable between2times a day and4times a day, but there was little differenceamong4times a day，6times a day and8times a day. Comprehensive consideration,the optimum stirring times is chosen4times a day.Finally, four most representative samples from the above experiments were selected,analyzed by GC/MS about the aroma materials. It showed that the wine fermented byK1yeast had less patterns of aroma materials, content was moderate, aroma wasslightly drab. The wine fermented by R2yeast had more kinds of aroma materials,content was moderate, aroma was rich. The wine fermented by DV10yeast had lesscategories of aroma materials, content was low, aroma was drab and thin. The winefermented by R-HST yeast had more kinds of aroma materials, content was low,aroma was thin. In conclusion, as far as aroma was concerned, the best yeast was R2,followed by K1and R-HST, and the last was DV10.Based on all the results of the experiments, the optimum parameters are as follows:nutrition is added when ferment to1/3, temperature is set12℃, stirring times is4times a day. The best yeast is K1and R2, K1applied to ferment ice wine with highquality and R2applied to ferment ice wine for bulk production.