I have no intention of ever intentionally touching my tongue to a bar of soap.Many times in "the old days" when you had to make your own lye using wood ashes (I've done that), there was scant methods to determine how strong the lye was along with lard or tallow that wasn't rendered properly. Then there is the wait time factor where the lye is changed into soap. I can tell if mine is done by touching a tongue to the bar - if it zaps ya - put it back on the shelf. Otherwise, most homemade soaps nowadays are very very mild. I love mine.