Popcorn Balls

2 quarts popped popcorn
1 cup packed brown sugar
1/3 cup water
1/3 cup dark corn syrup
¼ cup butter
½ teaspoon salt
1 teaspoon vanilla extract
Place popcorn in a large bowl; Set aside. In a heavy saucepan, combine brown sugar, water, corn syrup, butter and salt. Bring to boil over medium heat, stirring constantly. Continue cooking without stirring until a candy thermometer reads 270 degrees. (soft crack stage).
Remove from heat and stir in vanilla. Pour evenly over popcorn. When cool enough to handle, quickly shape into balls