Potrero Straight Malt Whiskey Finished in Port Barrels is double distilled in copper pot stills from a 100% malted rye mash bill. It is matured for at least three years in fine grain new American white oak barrels, and then finished for one year in once used port barrels. The result is a deep reddish amber liquid with sweet and rich port notes balanced by the spiciness of rye whiskey.