You can only be a cult winery for so long. Eventually, the secret-handshake nature of your clients’ fandom becomes widespread, and then you’re just a regional mainstay. That was true at Heart & Hands, it was true at Damiani, and eventually it will be true at Bloomer Creek Vineyard. Not yet. There is still a sense of excitement among those who have visited Bloomer Creek in the past two years. There is a kind of illicit knowledge, an ahead-of-the-curve edge. The critical drumbeat is growing, but owners Kim Engle and Debra Birmingham have not seen an explosion in the tasting…