Add all ingredients to blender or food processor. Blend until smooth and all ingredients are incorporated. Taste and adjust seasoning - need a kick? Add the (or more) chipotle. Too thick? Add a little more water.
Put sauce into a medium saucepan and bring to a boil over a medium heat. Reduce to low heat and simmer for 10 minutes.
Cool to room temperature and then use or store in closed container in the fridge for up to 3 weeks.