Bring first 3 ingredients to boil in large saucepan over medium-high heat, stirring until sugar dissolves and brushing down sides of pan with wet pastry brush. Attach candy thermometer to sides of pan and boil syrup until thermometer registers 225°F, about 6 minutes. Mix in strawberries. Return mixture to boil, reduce heat, and simmer until jam thickens and thermometer registers 216°F, stirring occasionally, about 1 hour. Transfer jam to small bowl and cool. Cover and refrigerate.
