Port wine is one of the most desired fortified/sweet wines in the world, called Vinho do Porto, Oporto, Porto, or just Port. It is coming from Douro Valley in the northern part of Portugal as the name derives from the town, Porto. The modern history of port goes back to 1678 when a wine merchant from Liverpool sent his two sons near the city of Porto to buy wine because at that time the import of French wine was forbidden. So, the two sons have returned with rather delightful wine which later became the "Englishmen Wine", making a strong and long relationship between England and Portugal. The main grape varieties for the production of the red port are Touriga Nacional, Tinta Roriz(Tempranillo), Tinta Barroca, Tinto Cão, Touriga Franca, Trincadeira and for the white Sercial, Gouveio and Viosinho. Port wine is made in a very meticulous and simple way from the grape varieties planted in Douro Valley, as first it is produced wine, and then is fortified with the addition of distilled grape spirits at 77% vol. to stop the fermentation halfway leaving some residual, natural sugar in the wine and to lift the alcohol content. After that process, they are often stored and aged in barrels stored in cellars, before being bottled. There are many styles of port wine which are determined before the maturation period and the best ports have an alcohol content between 19-22% vol. and a residual sugar content between 40-60 g/l. Colheita style derives from the Portuguese word for "harvest" as it is a vintage port, one could also call it old tawny or vintage tawny. It is left to mature at least seven years in wooden barrels, and the label must indicate the vintage, the date of bottling and the barrel ageing. Crusted Port is another style, which is a blend of good vintages, but which do not reach the quality of a vintage. It is bottled young after a maximum of three years, usually without filtration, wherein the process of maturation for a few more years it forms sediment at the bottom of the bottle and a crust on the bottle walls. LBV (Late Bottled Vintage) is a less expensive style of the Vintage Port made from grapes from one vintage year, which matures for at least four to six years in barrel and/or tank. The Ruby style is the fruitiest and cheapest one with strong ruby to cherry red colour, which gives the wine its name, results from the low oxidation and short ripening period. It is blend of a couple of vintages of young wines and matures in barrels or steel tanks for two to three years and it is filtered. Ruby Reserve style is a black-red, tannic and fruity type, previously known as Vintage Character, but it was banned in 2002 to avoid confusion with the real Vintage Port. Several vintages are blended to be created and compared to the Ruby, it matures longer, with four to five years in the barrel. The Tawny style is a type that matures in the barrel at least for three years, and with longer maturation, it develops the colour from amber to mahogany and from there derives its name. This type of port wine also contains a larger proportion of white wines and lighter red wines in the blend, always made from several vintages. It is not often a 20, 30 or 40-year-old Tawny port to be produced. There are different styles and types which are called "Fine Tawny" or "Fine Old Tawny" or "Aged Tawny". The Vintage Port is the best port from a particularly good or great vintage, which occurs at best three times in ten years, and it shares only 1% of the whole production of port wine. Each producer decides whether to declare a vintage year or not, and all of them produce a vintage in the same year. This style is vinified reductively and produced from a single vintage, and normally matures for two to a maximum of three years in the barrel and then is bottled. It is ready to drink after 10 to 15 years maturation in the bottle, but it is only after at least 20, 30 and even more years of bottle ageing that it reaches the highest perfection with incomparable oiliness, fragrance, fullness and delicacy. The White Port is produced from white grape varieties with similar winemaking process to that of red port wine, but the mashing time is much shorter or it is not made at all. It is aged for two to three years, mostly in the tank, and has a relatively low alcohol content of about 15% vol. It ranges from dry to sweet, and those that mature longer in wooden barrels develop a golden yellow colour and a nutty taste and can also be kept for decades.