<P> Samuel "Sam" Winchester is a fictional character and one of the two protagonists of the American drama television series Supernatural along with his older brother Dean . He is portrayed by Jared Padalecki . </P> <P> Sam was born on May 2, 1983 to John and Mary Winchester in Lawrence, Kansas . He is one of two focal characters of the series . He is the couple's second child, four years younger than his older brother Dean . He is named after his maternal grandfather, Samuel Campbell . </P> <P> When Sam was only six months old, his mother Mary was killed by the demon Azazel, whom his mother walked in on while he was feeding Sam demon blood . Sam is saved from the ensuing fire by his father, who then gives him to a four - year - old Dean to carry outside . Since that moment, Dean has felt responsible for Sam and became Sam's protector, partially due to pressure from their father to keep his brother safe . </P> <P> Sam and Dean spent their childhood moving from town to town every few weeks while their father hunted supernatural beings and their mother's unknown killer . Until the age of 8, Sam believed that his mother had died in a car accident and his father was a traveling salesman, until Dean revealed to him the existence of the paranormal . Sam apparently started hunting alongside his brother and father around the age of twelve, however, he began wanting a normal life without monsters; years later, a teacher encouraged him to carve out a life away from the "family business" after reading Sam's story about a werewolf hunt . At nineteen, after a heated argument with John, Sam leaves for Stanford University, thus leaving his family and their hunting crusade behind him . </P>

When does sam start to drink demon's blood