Here's my BBQ sauce. I usually make it once or twice a year - I make a big batch & then can it in mason jars. I start with homemade 'ketchup' - my wife & daughter love ketchup, but don't touch this stuff, so it all goes into the sauce.
10 lb Tomato; totally ripe
1 Bell pepper, red; seeded
4 lg Onion; chopped
1 1/2 c Vinegar, cider
2 Garlic clove; crushed
1 ts Peppercorns
1 ts Allspice, whole
1 ts Cloves, whole
5 Cinnamon stick
1 ts Celery seed
1/2 t Mustard, dry
1/4 ts Cayenne
4 T Sugar, brown
3 T Sugar, white
1 ts Salt
Cut tomatoes in quarters and puree them in food processor along with bell pepper. Strain puree through a coarse sieve to move skins and seeds. (You can dump the puree into a colander and work it through with your hands until there is nothing left in the colander but a dryish pulp of skins and seeds. I save the pulp for later - see below) Now puree onions, combine with tomato and pepper puree, and pour into a large stainless steel or enameled kettle. Cook and stir occasionally over low heat until it is reduced by about a third and is considerably thicker. Meanwhile put garlic, peppercorns, allspice, cloves, cinnamon, and celery seed into the vinegar in a small pot and simmer covered for 1/2 hour to steep spices in the vinegar. Pour about half the spiced vinegar through a tea strainer into the thickened tomato mixture. Stir. Also add sugar, mustard, cayenne, and salt at this point. Here is where the tasting comes in. You can adjust any of these ingredients to suit you. You can add more spiced vinegar. Or a little plain vinegar. More or less sugar, mustard, cayenne. Just sort of tinker with it. Cook it some more, stirring often, until it looks like catsup should ook. Taste and adjust again. You may notice that it looks slightly curdled. Not to worry. Hit it a lick in the food processor. Smooths right out.
Next add some homemade pepper sauce - usually about a pint from the recipe below, but I've use Tobasco in a pinch.
2 cups assorted chiles, freshly picked, cleaned, and stemmed (mostly red, but you can mix a few greenies in for spice...experiment with what you like, but "fleshier" chiles make a smoother sauce. Also, I leave the seeds intact....too much bother to take them out, and I think they add a nice flavor.) I add about 2 or 3 tablespoons of the tomato pulp saved from the ketchup - it helps even out the color especially if you end up with a bunch of different colored peppers - brown pepper sauce is a little odd looking.
1 ts kosher salt
1/2 onion, red or white
Juice of 1/2 lime or lemon (I actually prefer lime, but only had lemon for this shoot)
3 large cloves Garlic
1 Cup White Vinegar, heated to almost boiling (turn your rangehood on for this one...fumes are pretty strong. I usually use the microwave for about 90 seconds....be careful though as vinegar boils sooner than water.)
Freshly ground black pepper
Put it all in a blender and puree until smooth.....may need to scrape it down a couple times.
Be careful when you take the lid off the blender....this stuff will burn your nosehairs out.
Cool, bottle, and age. You can start using it right away, but it will have a definite edge to it. Besides, it's still warm so it'll just be hot and salty. Makes about 3 cups of hot sauce. After a night in the fridge, it's ready for using. As it ages, it will mellow and blend, but loses some heat. You'll find that when "fresh", it has a hard bite up front. But as it ages a week or so it's a nice overall heat that you'll love.
Now the tinkering begins! I reduce about 4 bottles of homebrew (stouts or brown ales preferred) and then add it to the ketchup along with Brown sugar (about 2 cups), soy sauce, Worstershire sauce, as much pepper sauce as you think it needs, marjoram, thyme, rosemary, more garlic. Let it simmer and reduce. Maple syrup/Molasses both work to sweeten and thicken it - corn syrup can be used to thicken it. Wait until near the end because the longer you have the syrup or molasses on the heat, the greater the chance you'll scortch it (I learned the hard way).
The ketchup, hotsauce and brown sugar is the base - every thing else is personal taste and each time it comes out a little different. Although my wife says each time it gets better and better. She hates when I make BBQ sauce because it takes the whole day, hates it more when we run out of the homemade stuff.