Sherry is a dry or sweet fortified wine from the Jerez region of southern Spain, though its name makes you think of England. It is produced from three main grape varieties: Palomino, Pedro Ximenez, and Moscatel. Making sherry is complicated, but the results can be sensuous.

Relying on a Finicky Yeast

Most sherries begin with the white Palomino grape. At the end of the aging process, Moscatel may be added for color and Pedro Ximenez for sweetness. Before aging, of course, comes fermentation, just like any other wine. After fermentation, the base wine is fortified through the addition of a grape spirit and barreled.

For those sherries destined to become Finos, Manzanillas, or Amontillados, a yeast called flor forms on the surface of the wine in the barrels. The flor influences the wine's flavor, producing compounds called aldehydes, and creates a protective layer like a crust on top of the wine, slowing oxidation. For the flor to form, the wine must be high in acidity (food for the flor), and the environment must be humid.

The flor plays no role in sherries destined to become Olorosos or one of the sweet versions. Olorosos develop their unique flavors through controlled oxidation.

The Solera Method of Blending

As the sherries age in barrel, they are subjected to one of the most fascinating blending operations in all of winemaking, known as the solera system. Imagine rows and rows of casks all stacked on top of each other — up to 14 tiers. The oldest wines are on the bottom and the youngest on top.

Producers remove about a quarter to a third of the wine from the bottom barrels and bottle it. They replace what they just removed with a wine from the next oldest, one tier up. This cascading of sherry from the younger to the older continues all the way to the top. By blending all these wines together, you get an enormously complex product. Sherries are not vintage dated, so it's perfectly fine to blend wines together from different years.

Types of Sherry

Not all sherries are created equal. They range in style from bone dry to so syrupy sweet you could pour them over ice cream. Here are the ones to know:

• Fino sherries are produced with the help of flor. They are typically pale and dry with aromas that might remind you of roasted almonds.

• Manzanilla sherries are basically fino sherries, but the type of flor yeast used in their production is unique and gives the wines a more aromatic character. The yeast is Saccharomyces beticus, and it thrives in the more humid climate of Sanlucar de Barrameda, a town in the Jerez region.

• Amontillado sherries are unique because they continue to age in barrel after the flor dies, picking up added personality through oxidation. Pale cream sherries are amontillados.

• Olorosos develop completely without the influence of flor. Dry olorosos do exist, but many of the famous ones are sweet.

• Many sweet sherries are made from the fermented juice of the Pedro Ximenez or Moscatel grapes. Flor does play a role in these wines. Palomino is often nowhere in sight, although winemakers are perfectly free to add dry sherry made from the Palomino grape to these wines to enhance their personality.