I use BrewTarget on Linux. Specifically Fedora 18. It is great it does most everything the commercial programs do and is very easy to learn. I have become a 50/50 mead maker vs. all grain brewer these days. That said, it clearly has problems with mead calculations (and I can assume wine calcs too) but for beer it is awesome. Try it, you have nothing to lose.
Edit: I should mention It works on Macs and Windows too, perfectly. Most assume this ... but as a Linux user I like to specifically point this out as users search for this knowledge.
Edit: I should mention It works on Macs and Windows too, perfectly. Most assume this ... but as a Linux user I like to specifically point this out as users search for this knowledge.