A solera consists of four or five rows of barrels stacked one on top of the other. The oldest wine is in the bottom barrels and the youngest is in the top. Wine is bottled from the bottom barrels which are topped up from the those in the level above. Those barrels are topped up from the barrels above them, and so on. New wine is added to the top barrels The new wine gets its flavor from the older wines and the quality and flavor is maintained. The process takes three years.