Yeah, my understanding is that tannat can be hit or miss. Besides being very tannic, I've heard that its also very acidic. Most of the wineries here in IN use it for blending with less tannic varieties. The best blends I've tried were blends with cab franc, another variety I think I can get away with. I say that because I'm in a location that makes vinifera very tempting to try growing but the time investment and the climate i'm in makes me equally hesitant.