Brian - if your Pinot Noir tastes like your Grenache, you’re in a VERY interesting place!
I think some grapes have very distinctive personalities that trump almost everything. For example, Cab Sauv somehow tastes like Cab more often than not, wherever it’s grown. I associate some herbal notes to it. Riesling tastes like Riesling. But then again, that may be simply because people plant those grapes in places that let them produce wine that’s similar to what I’m used to. I don’t really know.
Syrah on the other hand, is actually quite different when planted in different places. It can be light and ethereal or heavy and thick. So if I have Syrah from Austria, I tend to like it, as it’s often got a touch of bacon and some pepper and it’s rather lighter in weight than what I drank last night, which was Pride Syrah and which was much bigger and heavier. That didn’t have any of the notes that I like. It wasn’t bad though, albeit not something I’m likely to want frequently. But I don’t find anything similar between that and something from Austria, or between either of those and something from Hermitage. They’re all good, they meet Rick’s criteria of being distinctive, but they don’t have a lot in common.
It’s why I was interested in the Tempranillo and why I still am. I think that Tempranillo has a distinctiveness that becomes more apparent with age, and I’m curious to see whether that’s in fact true or only something I know from Spanish wines.
I agree that you’d look for a similarity between wine made from a grape by several producers in a region AND a difference between that group of wines and wines made from other varieties. However, we shouldn’t imagine that wine should only be monovarietal - blending different grapes can produce more complex wines and I would hope that the blend would highlight the region. So ultimately, I suppose what I’m looking for is a combination of distinctiveness and “goodness”. It’s no use finding a wine that’s distinctive if the wine just sucks. But if it just tastes like something generic, that’s of no interest either.