Spanish term (also solera criadera system) for the traditional storage and blending system of younger and older wines, i.e. different vintages in the production of sherry. However, the process is also used alternatively in the production of Madeira, Malaga, brandies (brandy, whisky, etc.) and vinegar (wine vinegar). The name is derived from the lowest row of casks (solera = "lying on the bottom"). Most sherries go through six to seven, in extreme cases up to 14 solera stages. Every year, a part (up to one third) of the fully matured sherry is taken from the lowest row of casks for bottling and marketing. From the bottom to the top, the wine is removed (saca) and refilled (rocío) from the row above. The average ageing time for a wine in the solera system is given by the quotient when the total wine stock in a solera system is divided by the quantity of the annual extraction. The quotient must be greater than two. A wine may thus be marketed after two years at the earliest.
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Egon Mark
Diplom-Sommelier, Weinakademiker und Weinberater, Volders (Österreich)