Combine all ingredients in a large, heavy saucepan; bring to a boil. Reduce heat, and simmer until slightly thick and reduced to 4 cups (about 50 minutes), skimming foam from surface of mixture occasionally. Cool; pour into an airtight container. (Mixture will thicken as it cools.) Cover and chill.
Note: Refrigerate preserves in an airtight container for up to three weeks.