I just added 1.5 pounds of blackberries (smashed up in a food processor, almost to the point of being liquid) into my lambic/sour. That was a month ago. The flavor isn't really fruity or sweet, but they are definitely there. The color hasn't been affected too much, either.
Jeff, Brewer, Troegs Brewing Company, Harrisburg, PA
"No, just do it right, damnit!"