In 3-quart heavy saucepan, mix granulated sugar, water, corn syrup and food color. Heat to boiling over medium-high heat. Boil uncovered 15 minutes, without stirring, to 300°F on candy thermometer or until small amount of mixture dropped into cup of very cold water separates into hard, brittle threads. (Watch carefully so mixture does not burn.) Immediately remove from heat. Let stand until bubbling stops.