Combine all ingredients in a sauce pan, excluding the sherry.
Adjust the amounts to personal taste and bring to a boil.
Once boiling, add the sherry (this helps to keep the flavor).
Simmer for at least 1 hour.
Notes
If using this sauce while grilling, use half the barbecue sauce to marinate the meat for at least 4 hours or overnight. Save the rest of the sauce to baste while cooking and for the finished meal.