Some California varietal wines — especially the “better” vintages from years in which climatic conditions were superb — age remarkably well or even improve with aging. However, it’s perfectly fine to drink California wines without waiting for them to “come around.” This is true for the vast majority of wines from the Golden State.
Discussions about older wines and aging wines are based on the presumption that the wines have aged in proper conditions, such as a temperature-controlled cellar or a special wine-storage refrigeration unit.
Generally speaking, California red wines age much better than California whites. The following describes how well the six major California varietal wines hold up over time:
Cabernet Sauvignon
Cabernet Sauvignon and Cabernet blends are definitely California’s longest-lived wines, by a wide margin. Even many California Cabernets from the 1940s, 1950s, and 1960s are mostly still fine to drink. But of course, not every California Cabernet will age well; only certain wines from the better vintages can stand the test of time.
Zinfandel
Red Zinfandels definitely age well; many 30-year-old Zinfandels are delicious. But Zinfandel does lose its characteristic berry-like flavor with time and in fact comes to resemble Cabernet Sauvignon. If you like the taste of young Zinfandel, you should probably drink your Zinfandels within 15 years.
Merlot
Not many California Merlots have been around long; before 1985, most winemakers used Merlot mainly as a blending wine. Generally, California Merlots are ready to drink sooner than California Cabernets; they’re usually softer, fruitier, and less tannic than Cabernets. Some believe that most Merlots will not age as long as Cabernets and are at their best within the first 12 to 15 years.
Pinot Noir
Generally speaking, Pinot Noir wines from a fairly low-tannin variety don’t age as long as Cabernet Sauvignons. To be on the safe side, you may prefer to drink California Pinots that are less than 10 years old so that all the wonderful, fresh aromas and flavors inherent in this variety are still at their peak.
Chardonnay
A few of the very best California Chardonnays can age and even improve with up to 15 years of aging — the likes of Hanzell, Long Vineyards, Mount Eden, Matanzas Creek, and Stony Hill, for example. But generally speaking, California Chardonnays more than 10 years old can be disappointing. Therefore, you may want to drink Chardonnays within 10 years of the vintage — with the exception of those few Chardonnays that have a proven track record for aging.
Sauvignon Blanc
California Sauvignon Blancs for the most part are best when they’re young and fresh; most will not age well or improve after 5 or 6 years. Of course, there are exceptions: Robert Mondavi’s very limited-production “I-Block” To Kalon Vineyard Fumé Blanc — from a vineyard planted in 1945, the oldest Sauvignon Blanc vineyard in the U.S. — can probably age for decades. Mayacamas Vineyards also makes a long-lived Sauvignon Blanc.
From: http://www.dummies.com/how-to/content/how-different-california-varietal-wines-age.html