Combine and whisk all ingredients except for the ketchup in a medium saucepan over medium-high heat until it comes to a simmer but not a boil, whisking to dissolve.
Reduce heat to medium-low and whisk in the ketchup. Stir frequently and continue to simmer over low heat for 15 to 20 minutes, or until the sauce has reached the desired thickness.
Use it while warm or cool, bottle and refrigerate for up to 1 week or longer if sealed in a sterilized container.
Recipe makes about 2 1/2 cups of BBQ sauce.
Easily scale up the recipe to make more.
If you will be basting with the sauce, then you might want a thinner consistency as it will thicken when cooked again on the meat. If serving at the table, you might want it thicker. Just simmer for less time to keep it thinner and for longer to make it thicker.
Monitor carefully when simmering and be ready to stir and reduce the heat if it starts to bubble and splatter.