Is this possible or would the salt and coriander need to be added at the end of the boil for the Gose? I`ve got 7 gal of wort souring that I was planning to split for 2 different berliners, but now thinking if possible to turn the second 3gal batch into a gose.
From the one Gose I've brewed and the fact that I'm doing a similar tactic this weekend, I would say you're going to need to boil separately as the salt and coriander are added during the boil. Maybe you can throw salt and coriander in the fermenter after the boil, but I don't know what type of results you would achieve.
This is definitely possible. The salt is the easy part, as you can just make a saline solution on your stovetop with just enough water to dissolve your salt addition. I'm assuming that you could get a reasonable coriander aromatic pickup by giving it a brief simmer in the same solution, although I have not tried it personally. Then, cool your solution and pitch it straight to the fermentor. I usually do about (1 lb/10 bbl) of (salt/finished beer) if that rate helps at all. A little bit goes a long way, and you can always add more later. Cheers!