Vineyards and cellars of Port Wine -> Bar do Binho

Part II/I

  The spirit promptly kills the yeasts so that no further fermentation can take place. In this way some of the natural sugar of the grape is retained in the now fortified wine and is responsible for the luscious sweetness of Port.
  Treading is still practised in many of the finest properties of the Alto Douro. Wines of outstanding quality are produced by this time-honoured method.
  Nowadays, however, by far the greatest proportion of Port is made in modern wineries by mechanical means. The wisdom acquired over three centuries of Port prodution by the traditional methods combines with the latest techniques of vinification.
  The grapes are tipped into large hoppers, broken up in a centrifuge and then pumped into fermentation tanks. Sometimes known as "autovinifiers". these tanks operate by a natural method which simulates the treading process.

  This principle makes use of the carbon dioxide released during fermentation. The gas builds up pressure inside the tank between the surface of the must and the sealed top of the tank, forcing the fermenting must up a vertical pipe from the bottom of the tank into an open through at the top where it gathers.
  Eventually a valve releases the carbon dioxide and thus the pressure inside the tank falls and the fermenting must sprays back throught a central fountain over the skins and pips wich are floating as a cap on the must, in the same way as in the lagar.
  Again as in the lagar, this process continues repeatedly until aproximately half the natural sugar has been turned into alcohol and the must has absorbed sufficient colour, body and tannin. It is then run into a vat where the brandy is added to arrest the fermentation.
  The thick, heavy, purple young Port then begins its maturation. Some of it may be destined to mature for several decades. The wine spends the winter in the Alto Douro at the quintas and in the spring it is transported to Vila Nova de Gaia, The town on the south bank at the mouth of the River Douro, facing the city of Porto. This is where the shippers have their offices and "lodges", as the warehouses used for maturing Port are known.