In a large saucepan, bring water and basil to a boil. Remove from heat; cover and let stand 10 minutes. Strain and discard basil. Return 3-2/3 cups liquid to the pan. Stir in pectin and, if desired, food coloring. Return to a rolling boil over high heat. Stir in sugar. Boil 1 minute, stirring constantly. Remove from heat; skim off foam., Ladle hot liquid into hot half-pint jars, leaving 1/4-in. headspace. Wipe rims. Center lids on jars; screw on bands until fingertip tight. , Place jars into canner with simmering water, ensuring that they are completely covered with water. Bring to a boil; process for 15 minutes. Remove jars and cool.