Combine ketchup, both vinegars, brown sugar, soy sauce, Worcestershire sauce, onion powder, and granulated garlic in a saucepan. Simmer over medium heat for 2-3 minutes, stirring often.
Add broth or brisket drippings to the pot, and stir through. If you’d like a thinner, beefier sauce, I recommend adding more drippings. Broth is great, but doesn’t have the intense flavors you’d get from smoked brisket.
Simmer sauce for 2-3 more minutes, then add in the freshly brewed coffee.
Remove pot from heat and stir in the unsalted butter to silk the sauce. You don’t have to add butter, this is just a preference on my part. Taste sauce, and season with salt and pepper if needed.
Let the sauce cool for 10-15 minutes, before using. If making a batch ahead of time, then store sauce in an airtight container in the refrigerator for up to 10 days.