Place vinegar and peppers in a blender; cover and puree. Add 2 cups sugar; blend well. Pour into a Dutch oven. Stir in remaining 4 cups sugar; bring to a boil. Strain mixture and return to pan. Bring to a full rolling boil over high heat, stirring constantly. Stir in pectin and food coloring if desired. Continue to boil 1 minute, stirring constantly. Remove from the heat; skim off foam. Ladle hot mixture into hot sterilized 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 5 minutes. Remove jars and cool., Serve with cream cheese on crackers.