Wine is aged in two stages, the first ageing process takes place in a warm environment where the wine suffers a form of oxidation and where the bouquets are created and turn the wine into Madeira Wine.
The second stage takes placeover a period of years, when the wines are stored in casks in a cooler environment where they continue to develop and enhance their bouquet, due to the gradual evaporation of water.
Therefore in the course of time, the wines become more intense in alcohol, sugar, and dry extract and the bouquet becomes more enhanced. If the process of oxidation does not take place, it cannot be considered a Madeira Wine. Once opened, a bottle of Madeira Wine has an extensive life span, due to this oxidation process and also to the influence of the acidity in the volcanic soils, which allows the wine to keep its freshness.
There are two different types of Madeira Wines, blends and vintages. Blends are made from wines which are generally 3, 5, 10, 15 years old or more and are blended to reach an average of the age indicated on the bottle. Vintages are wines made from one single harvest. These wines are considered top quality wines, when they have been aged in casks for over 20 years and have reached the required quality. This traditional and natural method of ageing means that the wines are stored in seasoned oak casks in lofts under the roof of the old lodges in Funchal, here they benefit from the gentle warmth of the sun. No artificial heating is used for any of these wines. The word canteiro is derived from the name of the supporting beams that underpin the floor on which the casks are placed. These canteiro wines are stored in casks by variety, name and year of harvest.
The wines produced from “Tinta Negra” which is a Red Vitis Vinifera grape variety, are used to make the 3 year old wines. The four style names are: Rich, Medium Rich, Medium Dry and Dry. Their names describe their relative sweetness. These wines are aged by estufagem, which is the process of heating the wines in estufas. The wines are gently warmed up to temperatures of 45ºC by means of a coil pipe through which warm water is circulated. The estufagem process lasts for 3 months. Some “Tinta Negra” also ages in the natural canteiro process. These wines are used in some high quality blends after due time in cask.
The premium wines (the very fine 5, 10 and 15 Year Old wines, single harvest wines, and Frasqueira or Vintage Vintage Madeiras) are made with the following grape varieties: Sercial, Verdelho, Bual, Malmsey and Terrantez. These wines are exclusively aged by the “canteiro process”.
The oenologists tasted all the wines regularly throughout the year and decides which wines will be used to make up a blend (of the same varietal) and which wines will be kept to make single harvest, colheita or vintage (minimum 20 years of ageing in cask – single year varietal). There is no maximum ageing period, although wines that are stored for very long periods can become too concentrated.
After the oenologists consider the wines have achieved their true characteristics, they are removed to a cooler area, to continue the ageing process more gently. The higher the temperature, the higher the risk of evaporation, so it is a fine balance between obtaining the right characteristics without losing too much of the wine in the process.