The name Solera is given in Spain to a series of casks of wines in process of maturation, so arranged as to provide for progressive fractional blending, thus insuring the continued production of a wine of even type in spite of differences which may occur between the produce of successive vintages. In the case of other wines the process of mixing is practised at the times the wines are completed and just before they are sent to market. In the making of sherry wine, however, the mixing begins at the first and is continued progressively until the wine is finished. It is evident, therefore, that a wine subjected to the Solera process cannot be of any one vintage, though the final product may be all from one vineyard. In this way there is eliminated the distinctions which occur in wines of different vintages, so that the product when finally completed is practically of a uniform character, in that the peculiarities of many seasons of vintages are blended into one expression. Inasmuch as there is a regular recurrence of peculiarities in different seasons, the final product must be practically uniform.