1. Rinse, stem and crush grapes thoroughly in a 6 to 8 quart saucepan one layer at a time. Bring to boil. reduce heat to low; cover and simmer 10 minutes, stirring occasionally. Cool a little. Pour prepared juice in a 3 layer cheesecloth and hang, let drip for at least 1/2 hour.
2. Measure 4 cups of juice and add to 6 to 8 quart saucepan. Mix in Certo. Bring mixture to a full rolling boil (a boil that doesn’t stop bubbling when stirred) on  high heat, stirring occasionally.
3. Add all the sugar. Return to hard boil for 1 minute. Remove from heat and let cool for at least 5 minutes, stirring occasionally.
4. Ladle in prepared jars, cover with 2 piece lids. Place in canner and bring canner to a gentle boil for 10 minutes.