Now that the production of Sherry has had time to sink in I want to go into Port wine production. But, in case you missed it, you can click the link for Sherry Production Part 1, which discusses the types of grapes used to make Sherry, how the grapes are crushed and what goes into the fermentation process, Or you can go here for Sherry Production Part 2 and learn how Sherry is classified, how the Solera system works and what the process is for fortification.
As we have been focusing on fortified wines with this series, it probably comes as no big surprise to you that Port is a fortified wine. It’s produced almost exclusively in the Douro region of Portugal although there are other countries that produce their own styles of Port. It’s origin, however, is in Portugal. Most Port wines are blends of various grapes from different lots across several vineyards and vintages and range from ruby to tawny in color depending on the grapes used and the aging process.
I’m not going to go into the different styles of Port made as I want to focus solely on its production, but if you want to learn about Port wine styles, read Port Wine: To Ruby Or Not To Ruby. There are many more styles than you would think, so read, learn about wine and enjoy.
Similar to how grapes were crushed to make Sherry, the grapes used in Port wine production were traditionally crushed by foot in large granite troughs called lagares. However, as technology advanced in the 1900′s, temperature controlled tanks with large internal paddles that worked like pistons plunged into the must, crushing the berries and removed the skins in the process.
Over time other processes were developed to aid in the laziness of man, like the autovinificator, which was a tube that circulated the must to prevent a cap from forming. As CO2 forced liquid from the bottom of the tank up through the tube, a certain amount of pressure was reached. Once that happened, a valve flipped open and a jet of must rained down on the juice and skins, breaking up the cap and mixing everything together.
Another awesome spew machine was the pump-over fermenter. This beautiful mess maker pumped must up and out over the top of the juice as a rotating spray, like the fire sprinklers you see in department stores. This process also kept the must from forming as it churned the juice and skins.
The last of the great mixing endeavors was the rotary fermenter. This was a temperature controlled tank that spun or rotated to a timer, which again, broke up the cap and effectively stirred the must and skins.
With regards to the fermentation process, the yeast used is the native wild or indigenous yeast of the Douro. Once approximately a third of the sugars has been converted to alcohol, the juice is pulled off the skins. This is the point when the Port is fortified.
A note about Port wine fortification: Either a neutral grape spirit or Brandy is used to fortify Port wine. If you take the neutral grape spirit and age it in a wooden cask for a specified amount of time, it becomes Brandy. So, in essence, the two are the same.
Once the alcohol is added the yeast is killed and this stops the fermentation process. The resulting alcohol level jumps to about 20% with around 10% of sugars remaining (called residual sugar). These percentages, of course, are only approximations and will vary from house to house.
Next time we will finish Port wine production with maturation and blending. Learn about wine, keep reading.