Ever have one of those hair-brained ideas that you just can't get out of your head until you run it to ground? Well, mine is co-fermenting cold hardy grapes with wild blueberries. For some reason I even want to try Concord grapes with blueberries, even though I'm aware of the usual caveats about Concord wine. I think it has something to do with my current fascination with the health effects of anthocyanins, which are abundant in both blueberries and Concord. Also, both grow well here in the Northeast, so something about it just feels right. I actually did a 1 gallon test batch last fall with about 3 pounds of frozen blueberries and Concord concentrate (added sugar to bring it up to about 21 brix). Fermented open for a few days, as if the blueberries took the place of grape skins in the must. Then racked to secondary and racked again a couple months later. I've not done anything else to it. It's still aging, but tastes decent so far. I think what flaws it has are mostly because it's concentrate. It's a bit thin. I feel like it would be a lot better if I had used grapes or at least fresh juice. I can buy fresh Concord juice in the fall, so I'm thinking of getting 6 gallons of it and adding a few pounds of frozen blueberries as I did last year. Has anybody tried something like this? Any tips? I know a more orthodox method would be to ferment them separately and blend later, but the voices inside my head tell me to co-ferment. I guess I'm wondering about the potential benefits of things like enzymes, oak, tannin addition, etc. Anyway, any advice or discussion is appreciated!