I wouldn’t let anything touch beer that isn’t specifically vetted as food-safe.
A bit of Googling says that pure titanium should be non-toxic, but it won’t be pure titanium. Likely alloying components are aluminum and vanadium, and maybe those are ok, too … but you don’t really know, and you don’t know what else is in there, or what’s going to cause it to leach out, and in what quantities. Sure, it’s probably ok, but I don’t like to mess with “probably” when it comes to potentially ingesting metals.