Port is made from a large selection of different grape varieties. Once harvested at proper sugar level, they are crushed and fermentation is started just like normal red wine. Fermentation is purposely stopped with the addition of a neutral tasting brandy. This halts the fermentation so that there is quite a bit of residual sugar left, which is why port is sweet.

Ruby Port is aged in oak (barrels or foeders/tanks) for 3 years minimum then bottled and is meant to consume immediately. It is a vibrant red in color hence the name.