I believe that I read somewhere that in the early days of these here colonies beer was often brewed from squashes (including pumpkins) . But that said, canned pumpkin is more likely to be other squashes, AND, it is very likely that it is not the pumpkin flavor that people find so attractive about pumpkin beer (and perhaps wine) as much as it is the blend of spices. If it IS the spices that make the dish and not the vegetable itself then focus more on those spices and find a vehicle for using them in a wine IF (I say IF) you don't find that pumpkin wine works for you.