What does vintage actually mean on a wine label?
The year the grapes were harvested — not the year it was bottled, and not an indication of quality on its own.
Why the year matters at all. Wine is an agricultural product, and the growing season varies. Temperature, rainfall, sunshine hours and the weather at harvest all affect sugar levels, acidity, tannin ripeness and disease pressure in the grapes. Two bottles from the same producer and the same vineyard, a year apart, can differ considerably.
Where it matters most: regions with variable, marginal climates — Burgundy, Bordeaux, Germany, Champagne, England. Here the difference between years is genuinely large, and vintage charts exist for good reason.
Where it matters least: regions with reliably consistent weather, where vintage variation is modest and a vintage chart tells you little.
What a "good vintage" actually means. That conditions favoured the style the region is known for — not that every wine from that year is good. A competent producer in a difficult year frequently makes better wine than a poor producer in a celebrated one. Producer is generally a stronger signal than vintage, and this is the practical point most vintage discussion misses.
Non-vintage (NV). Common in Champagne and fortified wines. The wine is deliberately blended across years to maintain a consistent house style — which is a skill rather than a compromise, and NV Champagne is the majority of what is made. Vintage Champagne is declared only in years the house considers exceptional.
What vintage does not tell you: how long the wine will keep, and whether it is ready now. Both depend on style, structure and storage far more than on the year.
The point people get wrong most often: most wine is meant to be drunk young. The overwhelming majority of wine produced is at its best within a few years, and improves not at all with age. Only a small proportion — with the tannin, acidity and concentration to develop — rewards keeping.
Storage matters more than age. Heat, light and temperature fluctuation damage wine far faster than time does, and a badly stored old bottle is worse than a young one.