Consuming a Japanese Fermented Paste Used for Treatment, Miso, Made by Fermenting Rice - Jurisprudential Answers - Miscellaneous Issues, Vol 5

Ahmed al-Hasan Response:

There is no problem with it if the amount of alcohol formed in it is small and does not cause intoxication or its symptoms. Attention must also be paid to whether alcohol has been added to it. If added alcohol is present, it must be avoided, because they commonly add types of alcohol prepared for intoxication, and these are impure. Even a small added amount therefore makes the food impure.