During our excursion into the Douro River Valley, in search of port, we learned that the grapes for many “vintage” port wines are still stomped. This age-old practice known as Pigeage means “punching down” grape skins. As the grapes ferment in their juices, carbon dioxide forms during the process and causes solids to float to the top, which have to be pushed down again. This process would typically take a couple hours and, back in the day, was done by workers after a long day of working in the fields. As you might note this process was often done to music, most likely to keep one’s enthusiasm up. As it turns out, the pressure from human force is gentle enough so that the seeds won't break, which can release a less than ideal astringent taste into the wine. Then there is the additional advantage is that a human has the intuitive control over when to stop – unless, of course, you’re drunk.
This rendering is a from a cellphone photo of a photograph in the halls of the Vintage House in Pinhao which I have lovingly restored. The collection of photos at the Vintage House are really wonderful but worn and faded. And sadly the photographer is unknown.