How To Make Port Wine: Fermentation & Fortification
Once they are picked, the grapes are taken to the winery. On the Taylor estates they are carried in small trays to ensure that they are kept in perfect condition. On arrival in the winery they are evaluated by the wine maker and inspected on a sorting table before being de-stemmed. In the traditional process, still used to make the wines from Taylor’s own estates, the grapes are then placed in wide, thigh-deep granite treading tanks known as lagares. Here they are trodden by foot.
When about half of the natural sugar of the grape juice has been turned into alcohol by the fermentation, the wine maker gives the signal for the fortification process to start. The treading stops and the skins are allowed to rise to the surface of the lagar where they form a solid layer. The wine fermenting under this cap of skins is then run out of the lagar into a vat. As the fermenting wine pours into the vat, a very clean young wine brandy is added to it. This colourless neutral spirit, at strength of 77% alcohol, is usually added in a ratio of about 115 litres of brandy to 435 litres of fermenting wine although this proportion can vary.
The addition of the spirit raises the strength of the Port wine to a level where the yeasts responsible for fermentation can no longer survive. The fermentation stops before all the sugar in the juice has been turned into alcohol and some of the natural sweetness of the grape is thus preserved the finished Port wine.