Ruling on fermented Kefir (a mushroom or grain)
25-2-2013 | IslamWeb
Question:
there is a kind of mushroom/grain called "kefir" that people arround the world "report" it has numerous health benefits, but a certain amount of alcohol (0.8%-2%) emerges during its fermentation in raw milk.Moreover, it is believed that "Kefir" originated from the era of Prophet Mohammad (PBUH), but nothing in hadiths refers to such grains. I found contradiction,in online Fatwas, about it being halal or haram?.if it is prooved healthy, should one use it just for the purpose of treatment only? Should I stop consuming it & tell my acquaintances to do that? that is a big concern to me and i hope you can disambiguate this question for muslims.
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
If it is proved that there is a percentage of alcohol in that drink, then it is not permissible to get benefit from it, even if the percentage of alcohol is little for it was proved that the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, said:
Whatever causes intoxication when taken in a large quantity is also forbidden to take in small quantities
· "Whatever causes drunkenness when taken in a large quantity is also forbidden to take in small quantities
· "Any drink that causes drunkenness is prohibited." [Al-Bukhari, Muslim and others]
· "Any drink that causes drunkenness is prohibited and if something that fills a Faraq (a cubic measuring which equals about 9 kgs) causes drunkenness, then a handful of that thing is forbidden." [Ahmad, Abu Daawood, At-Tirmithi. (At-Tirmithi graded it Hasan and Al-Albaani graded it Saheeh)]
Al-Munaawi 
said in Faydh Al-Qadeer: "It refers to drinking it, i.e. if it causes drunkenness, then it is forbidden to be drunk, even if the one who drinks it does not get drunk with the amount he gets of it because it is very little." [End quote]
On the other hand, it is not permissible to use as medicine anything that contains a percentage of alcohol. It was reported in Saheeh Muslim that Taariq ibn Suwayd Al-Ju‘fi 
asked the Messenger of Allaah, sallallaahu ‘alayhi wa sallam, about wine and he forbade him to use it, so he said: 'I only make it as a medicine.' He, sallallaahu ‘alayhi wa sallam, said: "It is not a cure; rather it is a disease.”
Of course, this is the case if there is no dire need to use it and there was no other medicine that is free from alcohol that can replace it, otherwise, there is no blame on the sick person to use from it what wards off harm.
It is worth noting here that alcohol is the main ingredient that causes drunkenness in wine. If that percentage of alcohol is removed by evaporation or that its substance is changed completely into another substance, then there will be no harm in using it for the reason of prohibition is removed.
Allaah Knows best.