Like everything else we see in the world there is always old and young, with wine its no different. Vines can live upwards of 100 years old but that doesn't mean they produce the best wine made, or that they even produce enough juice to put into production. Depending on the AVA a 25 year old vine could be considered "old" so what is the big difference between old and young? Is it the depth of the root? Is it when it was planted? A certain type of grape vine in particular? Wine vines take a minimum 3 years before they produce fruit, 5 years before they produce enough fruit for an actual harvest worthy of production and last up to about 25 years hopefully with full production, if no complications occur such phylloxera which is a disease which attacks the vines killing them from the roots. After a vines first full harvest at 5 years old its yield slowly starts to decrease year after year creating a more concentrated, full flavor that most everyone enjoys. I mean do you really want to drink a acidic, flat, mineraly, no flavor wine? I don't. Don't get me wrong, there are great wines that are mineral, earthy toned wines that continue to dominate and are great wines and Old World countries such as France and Italy have perfected and protected those practices for centuries. The AOC and DOCG (check out my old world new world article to learn more) of France and Italy, just to name a few, tell vitners where, what, how and at what age they can use grapes from those vines. Truly creating "old vine" wine. Red Zinfandel in the U.S. is probably the most widely known and used grape for old vine wines but again that is all subject to opinion.
There are also practices that a lot of New World wineries and vitners do as well to create the simulation of what "old vine's" go through to create the same structure at an early age in young vines. Water deprivation or water deficit simulates what old vines go through in drier years. Considering old vine roots can reach upwards of 25 feet going through many different soil types and young vines maybe 6 feet reaching the middle part of the first layer, maybe, this is a strategic way to produce much more concentrated fruit at the earlier stages. But there is another factor to consider when talking about vines and fruit and that is coverage.
Coverage is one of the biggest factors when it comes to grapes and wine making. Kirk Grace vineyard manager at Stags Leap Cellars talks about this in a article on their website. The reality is coverage is what dictates under ripe from over ripe. Under ripe fruit can create over acidic tart flavors that strip the palate and have an overbearing nose, as to where over ripe fruit can be to concentrated doing the same with bold flavors and spice. At the end of the day Grace says the blend grapes from blocks that are 3 years old all the way up to 35 years old.
Wine is all subjective that is the important thing to remember and I will always stand behind that. Everyone's palate is different and everyone's style is different. Some people drive Cadillac some people drive BMW, that is what makes it fun, if we all did everything the same that would just be boring and insignificant and not worth writing, or talking about. Old Vines can be 25 years old all the way to 100+ years old.
Zinfandel as some may know is my favorite varietal and for good reason. Diversification of another level, color, flavor, body, aroma, mouthfeel, texture, finish. I can go on about why but that sums it up pretty much and I am sure that most winemakers who have had the chance to play with Zin over the years will tell you the same. Zin is the best Sin, corny I know but its true! It truely is the BEST! 
