An old vine Zinfandel.

The phrase 'old vine' appears quite often on California wine labels.  Old vines have a reputation for making better quality wines due to the concentration of all of the vines resources into fewer clusters of fruit.  But anyone who knows just a little about viticulture and oenology knows that this is a gross over-simplification, as there are a multitude of factors that together determine the eventual quality of a given wine, the least of which is the subjective experience of the individual taster.  In the United States there is no formal definition of exactly what constitutes an old vine.  Is it 30, 40, 50 years before the vines in a vineyard are deemed old?  All grapevines begin to produce less crop after 20 years and in the Napa Valley, for instance, 20 years can be pretty ancient for a vineyard.
The Rosenblum Cellars, 1991 Michael Marston Vineyard Zinfandel does not mention old vines on the front label, but on the back label it says: "These vines are over 85 years old...They produce a crop of less than one ton to the acre, but the fruit is spectacular in its intensity."  All well and good, but harvesting less than one ton of grapes per acre is not really viable from an economic standpoint, is it?  Wineries need to make a profit or they simply cannot continue making wine.  As a side note,   The Marston family no longer farm these low-yielding Zinfandel vines in their Spring Mountain vineyard (Spring Mountain became an AVA in 1993), they have replanted every block to Cabernet Sauvignon.
I didn't have high expectations for this wine, after all it was almost 22 years old.  Yes, I know, in the grand scheme of things this wine might not seem old when compared to some wine producing areas of the world - I'm thinking Bordeaux - however, this was a California Zinfandel and I personally don't think Zinfandels age particularly well.  Neither Vinomaker or I are quite sure how we acquired this wine, which can often be the case in Vinoland, but that makes trying older wines all the more fun, one never really knows what the wine will be like.  The tasting notes on the back label describe the wine thus; "...rich brambly blackberry and briary spicy elements in the bouquet with flavors of blackberry jam, spice and anise."  And I could very nearly agree with these descriptors if it wasn't for the fact that this wine had been thoroughly spoiled by brettanomyces.  Now, I usually have a higher tolerance for a touch of brett in wine, I am not as sensitive to this spoilage as Vinomaker is.  On this occasion my olfactory epithelium must have been working overtime because after three sips of this veritable mouse-bottom of a wine, I was done. However, Vinomaker didn't think it was that bad.  No biggie...brett happens!