Fortified Wine

In the making of fortified wine fermentation is interrupted earlier than in still wine, in order to prevent the total transformation of the must’s sugar into alcohol. Fortified wines have higher alcohol content than still wines. This is because fortified wines go through a winemaking phase called fortification, i.e., after fermentation, brandy is added to the wine. Fortified wines are stored in bottles or barrels, where they go through an ageing period (sometimes for decades) before being put on the market.

The harvest starts when the grapes are ripe and have the desired colour, acidity, weight and (especially) sugar levels. In the Douro region, harvesting is usually done between August (Douro Superior) and October (Baixo Corgo). This operation must be conducted carefully, which is why it is usually done manually.

The grapes are placed in containers that are later transported to the winery. It is necessary to ensure that the grapes don't get crushed or smashed during transportation, since this may lead to their fermentation and, consequently, make them useless for producing wine.

As soon as they get to the winery, the grapes are examined to check if they are in perfect condition. They are then unloaded to the receiving bin (a big container in the shape of an inverted pyramid), and some products are applied to them, in order to avoid their quick oxidation.

Destemming | Crushing
Destemming is the process in which the grapes' berries are separated from the ligneous parts of the bunch. After that, the grapes are placed in rock or stainless steel tanks (the first ones very common in the Douro region) to be crushed. In the Douro region it is still a tradition to crush grapes underfoot; however, nowadays mechanical models are used in most wineries.

Alcoholic fermentation
This is a very short process, usually of 3 to 4 days, in order for the wine to obtain very intense flavours. The must has to be in permanent contact with the grapes' skins (maceration), therefore it is constantly moving. Fermentation is a very rigorous process. An oenologist analyses the must and temperature (usually of 28ºC) on a daily basis. Fermentation ends when the amount of non-fermented sugar endows the wine with the desired sweetness.

Fortification is the process of adding brandy to the fermenting must. The must is separated from the solid parts (draining) and taken to the tanks, where fermentation is interrupted by the addition of brandy. Fortification improves the wine's chemical stability and controls its final level of sweetness.

The must is taken out of the rock or stainless steel tanks and the solid parts deposited at the bottom of these are transferred to presses. The presses mix the sediments to extract elements that are later added to the wine in order to endow it with more colour and aroma.

The wine is cleaned frequently: lees deposited at the bottom of the containers are removed. In racking, the wine is transferred to new containers so as to separate it from unwanted particles, let it breathe and gain better taste.

Wine is poured into wooden containers to age. Some wines age in stainless steel tanks because they have inferior quality and it is necessary to preserve their aromas and colour.

Wine is poured into tanks to be blended, i.e., the final wine is obtained by mixing several wines. This way, the wine has high quality and unique characteristics. Blending can be done with wine from one single harvest or from several ones.
Clarification eliminates particles that would only precipitate after bottling the wine. Younger and lighter wines are stabilised, i.e., are refrigerated at temperatures between 8º and 10ºC, with the intention of removing the elements that make the wine cloudy and not very crystalline. Filtering is only performed in Colheita wines, because their maturation process takes several years in oak. Even so, it is a light filtering.

The wine is bottled according to the maturation time desired by the oenologist. Port wines have different characteristics depending on the blending, maturation and sugar processes. For example: Tawny is aged in small barrels, while Ruby's ageing occurs in big containers.

The grapes are taken to presses, where they are mechanically transformed into juice. The juice is run down and taken to fermentation tanks. When this happens, one uses fermentation off skins (solid parts are not used in the winemaking process). If one uses fermentation on skins (fermentation with all the grapes' elements), the wine is fermented and only afterwards pressed.

Alcoholic fermentation
In alcoholic fermentation yeasts are added to the must, transforming the grapes' sugar into alcohol. The oenologist watches this process and, according to the grape variety and desired level of sweetness, finishes fermentation.

Fortification is the process of adding brandy to the fermenting must. In Malvasia and Boal, fortification is performed earlier to get sweeter wines. Verdelho and Sercial grape varieties produce dryer wines, so their fortification is done later.

Wines are heated and kept at a constant temperature of about 40ºC – 50ºC. They are kept in closed containers for about three months, without air circulation. Better quality wines undergo a slower evolution close to the place where heating takes place: the temperature is about 10ºC lower and ageing time is between 6 to 12 months. Leaving the wine under the eaves is a natural ageing process in which no artificial heat is applied. It is a slow process and produces the very best wines of all.
Cooling corresponds to an ageing period lasting for about 90 days. It is a slow and gradual process; otherwise it may impart a "burnt" taste to the wine. After that period, the wine is ready to be treated (clarified, filtered and blended).

In racking, sediments resulting from winemaking processes are eliminated. The wine is transferred to clean casks, but that is not enough to eliminate the particles in suspension. Therefore, to completely clear the wine, it is clarified and filtered.

The wine is bottled according to different ageing times: if it is a Reserva Extra, it has to age for at least 15 years; if it is a Reserva Especial or Velha, ageing time is of 10 years. Colheita has a minimum ageing time of 20 years in wood and 2 years in bottle, i.e., when the wine is bottled it doesn't mean that it is immediately put on the market.