sounds interesting. it is likely citric acid that is giving the sour. if you are interested in trying sour pitch this would be a good candidate. you wouldnt want to hop it though.Ok I'll take your advise and prime them to 3, better safe than sorry. The plan is hopping to 7hbu. No preservatives in the concentrate, and good idea to throw it in the freezer for the couple weeks it'll take to ferment out. The juice mixed to label strength is quite sour as it is. Originally I was going to kettle sour and brew 5gal. but I want to try a more concentrated cherry flavor so I'm cutting the batch down to 2gal. The acid in the juice will make it plenty sour on its own., remember this is tart sour cherry juice. If you've ever eaten a fresh sour cherry you know they pack a punch. This is an experiment, albeit a bit of an expensive one at $33.00 a 32oz bottle of juice, but I'll take one for the team and let you know how it turns out.
I would be surprised if the tartness carries through the beer. keep us posted on the progress.
Also what yeast are you using?