Solera
From EncycloWine
A solera is a series of barrels or other containers used for aging liquids such as Sherry, Madeira, Marsala, Mavrodafni (a Greek dark red fortified dessert wine), Muscat, Muscadelle, and Balsamic vinegar.
Typically, a portion of the wine from the last barrel of the series is removed and bottled. Then the last barrel is filled from the next-to-last barrel, etc., until the first barrel is filled with new wine. The barrels are then left to age until the process is repeated.
Wine produced from a solera cannot have a vintage date because it is the product of wines from many years. The last barrel in a solera has at least a tiny (albeit usually insignificant) fraction of the first wine ever put in it, which could be hundreds of years old. However, if the movement of wine is slow enough, it is possible to establish a minimum age of the blend. For example, if one has ten barrels, and transfers wine along once a year, the result is a minimum of ten years old, and can be labeled as such. However, the average age is older than that.
This process described above is known as solera in Spain, where Sherry is made, but is called in perpetuum in Sicily, where Marsala wine is made.
A solera can easily be the largest capital investment of a family winemaking firm, and the barrels used are usually passed down to one's descendants.
