Some readers may be interested to follow up on the result of this process. Well, the (bio-)juice of the fermented kaffir limes looks like light brown cloudy liquid, smells like a fruity wine and tastes like... No. I am not game enough to taste it. Because I have no ideas what micro-organisms have been living and growing in the juice.

I did tested the bio-juice as a cleaning liquid. Here is one test.

A number of cleaning agents were painted on a copper-bottom pot. Fresh kaffir juice on the left, water, baking soda, vinegar, a popular dish washing liquid and the bio-juice on the right.

The pot was left alone for 30 minutes. And the result is shown by the second photo.