In a large saucepan, put the water or stock, garlic, onion, and oregano. Cook for 2-3 minutes. Be careful not to burn the garlic. Add the remaining ingredients and cook over medium-low heat for 20-30 minutes until thickened. Place all ingredients in a food processor and process until smooth. To thicken further, return to a pot and cook over medium-low heat for 10 more minutes, or until reduced to desired thickness. Take care that the ketchup does not scorch on the bottom of the pan. This will keep well for 2 weeks in the refrigerator or longer frozen.