I use Homebrew Formulator as I one of those poor deluded Mac fools. It is however freeware and does the job so long as you can operate in lb, oz and F. If beersmith was on mac I'd be rattling off my credit card number like a mantra to get a copy.
Just so everyone knows Beersmith runs well under Wine in Linux too, a little fiddly to get it going but if you're already figured Linux it shouldn't be a problem.
I believe there's a Mac version of BeerToolsPro if you don't want to use an emulator, but TBH I didn't like BTP.