Kefir

In our understanding, this drink is made by immersing Kefir grain in a quantity of water. Obviously, it would take a considerable amount of time before the fermentation process (that creates intoxication) takes place. This is similar to how Nabeezh-ut-Tamar”/Date-infused water (mention of which comes in the Ahaadeeth) is made. Hence, the ruling of Nabeezh-ut-Tamar would apply in the case of the Kefir drink as well, that as long as it does not ferment, thereby becoming intoxicating, it would be permissible to consume. After it reaches the level of intoxication, it will not be permissible to consume, unless it is used for medical reasons under the advice of a reliable upright Muslim doctor when there is no other alternative for one’s ailment. 

If this drink is home-made, a person can still monitor it and ensure that it is consumed prior to fermentation taking place. If however, it is purchased off the shelf from a retail outlet, there could be a strong doubt that it had reached the intoxicating level before being bottled for the retail market. In that case, we would advise abstention as a Hadeeth tells us that “Discard that which carries doubt for that which does not carry any doubt.

Furthermore, Rasulullah Sallallahu Alayhi Wasallam said, “Whatever causes intoxication when taken in large quantities is also forbidden when taken in small quantities.”