Vintages are routinely glorified in the wine press. How do they come to the conclusion that a given year is superior? Is it a guarantee of quality?
A vintage refers to one annual growing cycle for the grapevine. The culmination is the harvest, which occurs in the early fall (or the early spring in the Southern Hemisphere). A perfect vintage would be one in which the weather was ideal from the early spring when the buds are breaking and flowering until the grapes are taken off the vine. The greatest threats are frost during the spring flowering, hail damage, excessive heat for an extended period and rain close to harvest time.
I think that the importance of vintage is often overstated. It should be viewed as a series of challenges that the growers and winemakers face. It will determine the size of the crop and the character of the wine, but it should not be viewed as a guide to finding quality. Great producers will make great wine in poor years, they will just make less of it. Conversely, a poor producer will make poor wine in a great year.