Sherry (Jerez - Xérès - Sherry) is a fortified wine originally produced in and around the town of Jerez, Spain; in Spanish, it is called 'Vino de Jerez'. A historic town with Persian name and during the Rustamid period called Xerex (Shariz, in Persian), from which Sherry and Jerez are derived. According to the Spanish wine authorities, Sherry must come from the legendary 'triangle' area in the province of Cadiz between Jerez, Sanlúcar de Barrameda, and El Puerto de Santa Maria. Sherry is made mainly from Palomino, Pedro Ximénez and Moscatel grape varieties. Sherry production is different from other wines because of how the fermentation takes place. The fortification is after the fermentation, all-natural Sherries are fermented dry and any sweetness is added later. It is made with grape spirit to around 15% Alc./vol. and then if intended to be a Fino style, a yeast called 'flor' is allowed to grow on the surface of the wine to protect it from exposure to oxygen. After that process is to be determined the style of the Sherry which can be from very dry to extremely sweet. There are nine styles including Fino - a pale and the driest of the traditional styles of Sherry. Manzanilla - a very pale style of Fino Sherry made near the port of Sanlúcar de Barrameda. Amontillado - 'flor' aged and then slowly exposed to oxygen, which produces a style darker than Fino. Oloroso - aged oxidatively for a longer time than Fino or Amontillado Sherries, producing a darker & richer style of Sherry wine. Palo Cortado is difficult to be found, as it is rarely produced. Matured and fortified without 'flor', it increases the richness of Oloroso and retains the crispness of an Amontillado. Blended or sweetened Sherry Styles are different labels for sweetened Sherry, based on their sugar content and flavour profile. The pale Cream style has between 45 - 115 grams of sugar per litre made with the base from Fino or Manzanilla, so it retains a bright colour & grape must is added as a sweetener. Medium is between 5 - 115 g/L. with base usually wine Amontillado. Cream - has between 115 - 140 g/L. with base wine normally Oloroso, sometimes Amontillado & blended with some Pedro Ximénez or Moscatel to sweeten. The Pedro Ximénez and Moscatel styles are extremely rich sweet wines that form the selected base for sweetening the base of dry sherries. These wines are rarely bottled on their own, though when they are the Pedro Ximénez makes one of the world's best dessert-style wines, having sugar levels between 200 - 400g/L. The Solera System is the process of maturing of wine and brandy by blending small portions of the contents from different aged barrels in such a way that the complete wine is a combination of ages with the average age gradually rising as the process continues over many years. Solera System ageing method was invented by the producers of Sherry, where the producer may transfer up to a third of each barrel, each year. Sherry which has been aged in the solera way has to be at least 3 years old when bottled. Sherry Solera is traditionally exposed to the sun, as the name tells. The sun rays stimulate an active fermentation process, ageing and development. It is build of several rows (called criadera) of small oak casks piled upon one another grouped by vintages. At the bottom is found the oldest and the most recent, the youngest wine at the top. Approximately one-third of the contents of each of the barrels on the bottom level is removed by the bottling. A new Sherry from the row directly above will replace what was removed and so on until a complete transfer is made from top to bottom. The wine-barrel is never completely drained, so some earlier wine always remains in each oak barrel. Traces of the very first wine put in the 'Solera System' may be present even after 50 or 100 years.