Combine all ingredients except the butter in a stainless steel or enamel pan. Bring the mixture to a boil, then reduce heat and simmer for 15 minutes. (Don't let it burn. Add a small amount of water if it cooks down too low.) Strain sauce into a clean pan. Add butter. Simmer until the butter melts. Stir with a wooden spoon until well mixed. Remove from heat. NOTE: This sauce keeps well in your refrigerator. Do not freeze.