There are many beer brewing novices heard some horrible news from the old hands about the higher alcohols,they said:“If higher alcohols in the beer level is too high will lead the drinker get a headache next morning.” For this reason,every novice brews beer gingerly.Today,let us talking about what is the higher alcohols,what is the feather? How to reduce the higher alcohols level?
Higher alcohols is the main constituent of fermentation metabolite,It main forms from the fermentation process,when the yeast breeding,the most content is isoamylol.
The higher alcohols has a important impact on the beer flavour,if it exceed certain content(The isoamylol’s threshold is 50mg/L),it’s has obvious fusel’s smell(like the smell of stinking socks),Simply put, if the content exceed more than 80m/L(It is related to the proportion of ester,the better proportion is 5：1)you will easy to get a headache next morning.
Through above to introduce how the higher alcohol produced theory,if we want to reduce the higher alcohols produced,we need to adopt below methods:
1) The strain of yeast
Because all the craft beer enthusiast will choose the common yeast strain-dry yeast,so we don’t talk all the details about this method,but we have to remember the different yeast will produce the different types of beer,so we need choose the right yeast.
2) The influence of yeast breeding
Higher alcohols is the by-product of yeast breeding (yeast breeding is divide two phases:aerobic breeding and anaerobic breeding),the yeast breeding quantity is decide the higher alcohols,it becomes direct ratio,wherefore control the yeast breeding quantity is very important.general yeast breeding quantity times is better control in 3-4 times.
3) Fermentation temperature
Raise the fermentation temper is good for yeast breeding,at the same time,it’s good for higher alcohols formed.
4) Yeast inoculation quantity
When the yeast inoculation quantity is higher,the new yeast cell will be little,it could lower the higher alcohols formed,if the quantity of yeast inoculation is too low,the new yeast cell will increase,,it could lead the higher alcohols get more(different craft beer has different yeast content,we suggest the highest concentration should control in 48million to 54million)
5) Yeast autolysis
If the yeast occur to autolyze in the after storage stage,the autolyzed yeast will raise the nutrition of beer,it will let the other active yeast becomes breeding and form the higher alcohols.
When the fermentation degree reaches about 30%,has 70% higher alcohols will be formed,when the fermentation degree reaches about 70%，all the higher alcohols will be formed,so we could raise the temperature appropriately.