port, a fortified wine made by adding brandy to arrest fermenting grape must which results in a wine, red and sometimes white, that is both sweet and high in alcohol. Port derives its name from oporto (Porto), the second largest city in portugal, whence the wine has been shipped for over 300 years, notably by English merchants. Port production varies considerably from year to year, partly because of the conditions of each growing season but also reflecting the benefício, the amount of wine that may be fortified each year, officially calculated according to stocks and sales. The average annual production during the first decade of the 21st century was 157,000 pipes (86 million l). The production of unfortified douro wine averaged 56 million l between 2008 and 2011.