There are six main grapes used for the majority of Port types: Touriga Nacional, Touriga Franca, Tinta Roriz, Tinta Barroca, Tinta Cão, and Tinta Amarela. Of course there are many other grapes that can and are used in the blend and each grape adds a unique component to the final assemblage. Some add aromatic charm, others body weight, complexity and richness, still other grapes bring a unique flavor profile to the party, but all have their place and raison d’être.

However, there are 64 red and 48 white grape varieties approved for use in Ports by the IVDP or The Port and Douro Wine Institute.  Up until the past two decades, many vineyards were a mix of those approved varieties. Winemakers and master blenders often had no idea which exact varieties were used in their Vintage Ports. Even many vineyard owners and their vineyard managers were mostly clueless about which grapes were growing on their properties. Until the late 1980s, most vineyards consisted of "field blends" with plantings of varying grape types mixed together. Now many vineyards have been replanted into sections of just one grape varietal, called "block planting." However, in recent years there has been a small push to go back to field blends where the vines are known and strategically planted together, then later picked and fermented together.

After the grapes are picked, they are either foot trodden in stone tanks, called lagares, or placed in large stainless steel or concrete tanks where they are crushed by mechanical means. They are then left in the tank or lagar for 1-4 days for fermentation during which the naturally occurring sugars are converted to alcohol. At the point when about half of the sugar has been turned to alcohol, aguardente (a clear neutral spirit made from grapes, often simply called “brandy”) is added to prematurely stop fermentation by killing the yeast cells. This also raises the alcohol content to about 20% alcohol by volume (ABV) and leaves a good deal of residual sugar in the Port. It is then transferred to large stainless steel or wooden tanks or casks to age for a minimum of two years. After that the Ports are selected for quality and it is determined what types of Port they will become. Obviously, this is a much simplified overview, but it will provide the basics, which could lead to further exploration and reading.