There are more than 10,000 hectares (25,000 acres) of vineyards in the Jerez region, where the predominant grape is the Palomino, named after a 13th-century Spanish knight. Grown elsewhere, the Palomino is an undistinguished grape prone to oxidation (darkening and spoiling), but due to the combination of soil and the prevailing humidity which allows the growth of the protective flor yeast, Sherry acquires its exceptional dryness and earthy aroma.
Like Port, Sherry is a "fortified" wine, meaning that extra alcohol is added to bring its alcohol content up to around 16 percent volume.
After the grapes are harvested in early September, they are crushed to make a still white wine which is aged for about two years before being put through the criadera and solera system, and blended to ensure that the finished product is of a consistent quality: rows of barrels are stacked in layers and a portion of wine, destined for bottling, is drawn off from the bottom row, called the "solera", which contains the oldest blend. These barrels are topped off with wine from the row immediately above, and so on to the top row of barrels, which are replenished with the most recent wine etc. For this reason, most Sherries are not vintage wines, more they are blends from different harvests. In exceptional years, some wine might be set aside for aging separately as Vintage Sherry, which is rare and correspondingly expensive.