Definition - What does Non-Vintage mean?
In the context of wine making, "Non-Vintage" refers to wines that are produced with grapes or wines from different harvest years. Non-vintage wines are typically blended with wines made from grapes of multiple years to create a consistent flavor profile from year to year, and these wines are mostly associated with Champagne and fortified wines like Port or Sherry, although vintners can also blend multiple vintages to produce consistent table or drinking wines.
WineFrog explains Non-Vintage
A wine that is labeled as "vintage" refers to a wine produced with varietals of a particular harvest year, thus a non-vintage wines is the opposite. Vintners produce non-vintage wines by combining wines made from multiple vintages to create a consistent flavor profile, so wine drinkers can enjoy the same flavor in their favorite wines from bottle to bottle, year to year. While non-vintage wines were classically used to make Champagne, and fortified wines; they are also used to make modern drinking and table wines. Using non-vintage wines allows the winemaker to make the wine style consistent and to reflect the style of the wine, not the vintage.
Non-Vinatge wines are different than Vintage wines, which are produced to express the characteristics of a specific vintage and would have subtle nuances that would reflect the terroir of the region and the growing region; these differences would make the same wine from one year, taste different than a wine from the previous or following year.