I tried once, but it imparted too much of a toothepaste like flavor. I added it to the secondary and in retrospect I probably added too much. It was quite strange tbh. Be careful and don't overdue it if you end up going through with it.
Thanks for the advice, what did you use for the flavoring??? My girlfriend is pretty content on me brewing something with peppermint and I figured a porter would work best.
They were peppermint leaves, but it was no porter. It was actually a mead. Either way I was just trying to caution you about how much you add. Peppermint porter sounds pretty good though. Mint and chocolate are always a good combination