Cross-posted at the Scotch Blog - an excellent resource for Whisky imbibers.
Now that you know a little about the epic history of Sherry, It's time to learn what all the fuss was about. Buckle up. I'll do my best to explain how Sherry is produced and which grape varieties are used to produce the various styles of this Spanish treat.
Part 2: "Waiter! There's a 100 Year Old Wine in My Sherry."
What would you say if I told you that a glass of 100+ year old wine will cost only a few bucks at a tapas bar? This is the beauty of Sherry. Sherry is a blended, non-vintage wine - and in some cases, a portion of the wine used in the blend is decades old. Sherry producers go to great lengths to produce a consistent 'house style.' In this respect, Sherry is similar to Champagne. Of course, in most other respects, Sherry is utterly unique.
Hot and Dirty
Jerez, the demarcated Sherry production zone, is situated in the southernmost region of Spain. The region's otherwise toasty climate is moderated by the Atlantic Ocean. Still, only a few miles inland, summer temperatures can reach 100F, while coastal communities enjoy much cooler air (~20F cooler). In addition to hot hot heat in the summer time, Jerez experiences essentially drought conditions from June through October. Grapes growing in this environment need to be tough. The luckiest vines grow smack-dab in the middle of the Sherry Triangle (the 3-town triangle, which forms the nucleus of Jerez). In this sweet spot, spongy, water-retaining Albariza soils slake the thirst of hot grapes during the hostile growing season. Albariza is a chalky, calcareous soil. In fact, vineyard sites within Jerez are ranked by the amount and depth of calcareous minerals within the soil.
Palo, PX and Mosca
Pre-Phylloxera, Sherry producers used many different grape varieties in their wine. Since vineyard replanting at the end of the 19th century, three varietals have risen to prominence: Palomino Fino, Pedro Ximenez (AKA 'PX') and Muscat of Alexandria (AKA 'Moscatel'). Palomino is the king-o; as it represents well over 90% of total vineyard area. Still, PX and Moscatel play key roles in the production of Sherry. Moscatel excels in sandy, non-Albariza soils, while PX produces intense, super-sweet wine.
Butts & Yeast
More important than grape varieties to the production of Sherry, is the manner in which the wine is fermented, aged and blended. Specifically, Sherry's unique character is due to butts (heh) and a unique yeast called flor. Nowadays, most of the wine in Jerez is fermented in stainless steel tanks. Once fermentation is complete, wine is poured into butts (heh, heh) - the name given to Sherry barrels. Butts (heh [last time, I promise]) are made of American oak, and hold 600 litres of wine. Depending on the style of Sherry to be produced (we'll get to the Sherry styles in just a minute), the butt (...) is filled to partial capacity (see pic, at right). Butts destined to produce lighter Sherry are filled less than butts used to produce heavier Sherry. The remaining air space is reserved for friendly flor yeast. Flor yeasts are endemic to the Jerez region. Flor is unique in that it produces a film over the top of the ageing wine, which protects it from rapid oxidation. The flor film feeds off oxygen in the butt (!) and alcohol in the wine. This yeast-wine interaction dramatically alters the scents and flavors in the maturing Sherry. However, were the butt/barrel to remain sealed, the poor flor would suffocate and/or starve to death; thus producing a rather unhelpful scum over the top of the wine. Fortunately, Sherry producers discovered that they could preserve the flor film by occasionally replenishing the butt with younger wine - providing new yeast cells, a fresh supply of nutrients and a puff or two of oxygen. This practice of recharging butts (I can't help myself) is the foundation of the Solera Reserva System, which is still used by all Sherry producers.
The Solera system is essentially a fractional blending of new wine with older wine in order to achieve a consistent house style. It works like this: Sherry butts are divided into graduated units; each unit comprised of a specific age, or maturation level of wine. These like-aged units are called criaderas (see figure at right. credit: Emilio Lustau House of Sherry). New wine is added to the highest ordered criadera (e.g. 4th criadera). A fraction of wine from this criadera is then added to the next criadera (e.g. 3rd criadera), which is in turn added to the next criadera, and so on. Butts containing the oldest wine are called the Solera. Each year, producers take wine from the Solera, bottle it and then replenish it using this system. In this way, a Sherry lover will be sipping a wine containing fractions of Sherry from several decades. For example, Sandeman's "Royal Esmeralda" is from a Solera established in 1894 - meaning a portion of this wine is over 100 years old.
Sherry's Shades of Style
The styles of Sherry are derived from its interaction with flor and the characteristics of the end product - whether it is dry or sweet. Of course there are also hybrid styles and brand-specific styles created by marketeers within the Sherry houses. Understanding all of these styles can become an exercise in confusion and/or boredom. Let's tease out the classic Sherry styles. Sherry is initially divided into two categories based on the wine's heft and flavor: Fino refers to the lightest, most delicate wines; while Oloroso refers to heavier, darker wine. Fino wines are fortified up to 15% alcohol with neutral grape spirits, poured into butts filled to 5/6th capacity and begin their Solera journey under yeasty flor film. Finos will be bottled as either "Fino" (confusing, I know) or "Manzanilla." Manzanillas are the same as Finos - its simply a difference in geography. Finos are from the area around the town of Jerez, and Manzanillas are from the community of Sanlucar. If, during the maturation process, a Fino, or Manzanilla, loses its flor covering, the wine becomes slightly darker due to increased oxygen exposure. Such wine will be bottled as "Amontillado." Finos and Manzanillas are light, tart and tangy. In contrast, Amontillados are heftier, slightly darker and offer nutty flavors. Amontillados may also be 'induced' from Finos/Manzanillas by upping the fortification above 16% alcohol. This knocks out the flor.
The heavier wines, that were initially classified as Olorosos, are fortified to 17%+ alcohol. This prevents flor from forming during the ageing process. As a result, Olorosos are directly exposed to oxygen. These wines are quite dark and full of nutty & biscuity flavors. Olorosos are commonly sweetened to produce Cream Sherry. It is interesting to note that due to the lack of flor, some Oloroso wine often evaporates during ageing. This results in concentration, and effectively increases the alcohol percentage - commonly over 20%. These sweet Sherrys are produced from sweet wine made from raisinated grapes. Historically, the Pedro Ximenez grape is used in Cream Sherry production. There are, of course, additional styles of Sherry. However, the above-mentioned styles are by far the most common.
In Part 3, we will explore the flavors of each of these Sherry styles and discover a few tapas to pair with this quintessential Spanish drink. In the meantime, your homework is to sample: