STTYLES OF PORT

Port from Portugal comes in several styles, which can be divided into two broad categories:

Wines that have matured in sealed glass bottles, with no exposure to air, and experience what is known as "reductive" aging. This process leads to the wine losing its colour very slowly and produces a wine which is smoother on the palate and less tannic.

Wines that have matured in wooden barrels, whose permeability allows a small amount of exposure to oxygen, and experience what is known as "oxidative" aging. They too lose colour, but at a faster pace. If red grapes are used, in time the red colour lightens to a tawny colour - these are known as Tawny (or sometimes Wood) ports. They also lose volume to evaporation (angel's share), leaving behind a wine that is slightly more viscous and intense.

The IVDP (Instituto dos Vinhos do Douro e Porto) further divides Port into two categories: normal Ports (standard Rubies, Tawnies and White Ports) and Categorias Especiais, Special Categories, which includes everything else.

GRAPE VARIETIES - PORT WINE

Over a hundred varieties of grapes (castas) are sanctioned for Port production, although only five (Tinta Barroca, Tinta Cão, Tinta Roriz (Tempranillo), Touriga Francesa, and Touriga Nacional) are widely cultivated and used. Although Touriga Nacional is the most celebrated Port grape, the difficulty of growing it and its small yields result in Touriga Francesa being the most widely-planted variety within the Douro. White ports are produced the same way as red ports, except that they use white grapes—Esgana-Cão, Folgasão, Malvasia, Rabigato,Verdelho, and Viosinho.

PRODUCTION OF PORT

Port is produced from grapes grown and processed in the demarcated Douro region. The wine produced is then fortified by the addition of a neutral grape spirit known as Aguardente in order to stop the fermentation, leaving residual sugar in the wine, and to boost the alcohol content. The fortification spirit is sometimes referred to as Brandy but it bears little resemblance to commercial Brandies. The wine is then stored and aged, often in barrels stored in "caves" (pronounced "ka-vess" and meaning "cellars" in Portuguese) as is the case in Vila Nova de Gaia, before being bottled. The wine received its name, "Port", in the latter half of the 17th century from the seaport city of Porto at the mouth of the Douro River, where much of the product was brought to market or for export to other countries in Europe. The Douro valley where Port wine is produced was defined and established as a protected region, or appellation in 1756 — making it the third oldest defined and protected wine region in the world after Chianti (1716) and Tokaji (1730).

PORT WINE

Port wine (also known as Vinho do Porto, Porto, and often simply Port) is a Portuguese style of fortified wine originating from the Douro Valley in the northern provinces of Portugal. It is typically a sweet red wine, often served as a dessert wine, and also comes in dry, semi-dry and white varieties. Fortified wines in the style of port are also produced outside of Portugal, most notably in Australia, South Africa, Canada, India, Argentina and the United States. Under European Union guidelines, only the product from Portugal may be labeled as Port. Elsewhere, the situation is more complicated: wines labelled "Port" may come from anywhere in the world, while the names "Dao", "Oporto", "Porto", and "Vinho do Porto" have been recognized as foreign, non-generic names for wines originating in Portugal. 

MISTELLE

Mistelle (sifone in Italian, mistela in Spanish) is sometimes used as an ingredient in fortified wines, particularly Vermouth, Marsala and Sherry, though it is used mainly as a base for apéritifs such as the French Pineau des Charentes, It is produced by adding alcohol to non-fermented or partially fermented grape juice. The addition of alcohol stops the fermentation and, as a consequence Mistelle is sweeter than fully fermented grape juice in which the sugars turn to alcohol.

FOTIFIED WINES

Although grape brandy is most commonly added to produce fortified wines, the additional alcohol may also be neutral spirit that has been distilled from grapes, grain, sugar beets, or sugarcane. Regional appellation laws may dictate the types of spirit that are permitted for fortification.

The source of the additional alcohol and the method of its distillation can affect the flavor of the fortified wine. If neutral spirit is used, it will usually have been produced with a continuous still, rather than a pot still.

During the fermentation process, yeast cells in the must continue to convert sugar into alcohol until the must reaches an alcohol level of 16%–18%. At this level, the alcohol becomes toxic to the yeast and kills it. If fermentation is allowed to run to completion, the resulting wine will (in most cases) be low in sugar and will be considered a dry wine. The earlier in the fermentation process that alcohol is added, the sweeter the resulting wine will be. For drier fortified wine styles, such as sherry, the alcohol is added shortly before or after the end of the fermentation.

In the case of some fortified wine styles (such as late harvest and botrytized wine), a naturally high level of sugar will inhibit the yeast. This causes fermentation to stop before the wine can become dry. 

FOTIFIED WINES

Fortified wine is wine to which a distilled beverage (usually brandy) has been added. When added to wine before the fermentation process is complete, the alcohol in the distilled beverage kills the yeast and leaves residual sugar behind. The end result is a wine that is both sweeter and stronger, normally containing about 20% alcohol by volume (ABV). The original reason for fortifying wine was to preserve it, since ethanol is a natural antiseptic. Even though other preservation methods exist, fortification continues to be used because the fortification process can add distinct flavors to the finished project.

Fortified wine is distinguished from spirits made from wine in that spirits are produced by means of distillation, while fortified wine is simply wine that has had a spirit added to it. Many different styles of fortified wine have been developed, including port, sherry, madeira, marsala, and vermouth. 

Although grape brandy is most commonly added to produce fortified wines, the additional alcohol may also be neutral spirit that has been distilled from grapes, grain, sugar beets, or sugarcane. Regional appellation laws may dictate the types of spirit that are permitted for fortification.

The source of the additional alcohol and the method of its distillation can affect the flavor of the fortified wine. If neutral spirit is used, it will usually have been produced with a continuous still, rather than a pot still.

During the fermentation process, yeast cells in the must continue to convert sugar into alcohol until the must reaches an alcohol level of 16%–18%. At this level, the alcohol becomes toxic to the yeast and kills it. If fermentation is allowed to run to completion, the resulting wine will (in most cases) be low in sugar and will be considered a dry wine. The earlier in the fermentation process that alcohol is added, the sweeter the resulting wine will be. For drier fortified wine styles, such as sherry, the alcohol is added shortly before or after the end of the fermentation.

In the case of some fortified wine styles (such as late harvest and botrytized wine), a naturally high level of sugar will inhibit the yeast. This causes fermentation to stop before the wine can become dry.