1. Brown Sugar
Brown sugar is key to a good rub and sauce. My personal blend of spices is usually a little on the hot and fiery side, so the sweetness and depth of molasses balances everything out really smoothly. I usually opt for dark brown sugar, which has a higher molasses content (and is vital for a rich and dark BBQ sauce). As a general rule, brown sugar should make up about 1/3 to 1/2 of the volume of a BBQ spice rub.
2. Chili Powders
There are 3 basic types of chili powders that should be included in a BBQ spice rub, for optimum flavor and balance: sweet, smoky, and spicy. I use a sweet paprika, a mild smoky chili powder, and an Indian hot chili powder for mine. Chili powder is, next to brown sugar, the most heavily used ingredient(s) in a BBQ rub, so make sure you have plenty on hand! Chili powders should comprise 1/3 of the volume of your rub.
Finely ground sea salt is perfect for this rub and sauce. It has a higher salinity than table salt, and lacks that medicinal aftertaste of kosher and iodized salts. I prefer it for all of my cooking, so naturally it's what I use in my BBQ. I recommend tasting as you go with this one - it is easy to over-salt, so add it gradually and slowly.
Other ingredients I use in my spice rub include:
Granulated garlic - fresh garlic can't be incorporated as evenly, so I use the powder version here
White pepper - I use more of this than black pepper, which tends to burn during the cooking process
Black pepper (freshly ground) - a little bit goes a long way
Ground cumin - this adds a really nice southwestern-style flavor to the rub
Rinse with cold water and thoroughly dry your cut of meat with paper towels. Rub that spice mix in! I make a crust on the outside of all sides of the meat, and really pack it on as tightly as I can until it won't stick anymore. I recommend refrigerating for 8-12 hours (sometimes, for my ribs, I marinate one or two days in advance, so that the spice rub flavor has plenty of time to penetrate the meat).
Even if you only have an hour or two to let it sit, make sure you give all of those flavors plenty of time to sink in.
Low and Slow!
Be patient. Good barbecue takes a long, long time. The tenderness of the meat you are cooking relies on cooking at a low temperature (200F, or 100C) for several hours. For a full rack of ribs, this means 6-8 hours mininum. The pork loin pictured here took about 4 1/2 hours. Don't worry, it won't be overcooked as long as you keep your temperature low. Make sure to let the meat rest after cooking, before you cut into it - this helps the juices to redistribute before you eat, so that every bite will be juicy and worth all of your time and effort.
Try to make double the rub you will need, because the other half turns into a fantastic BBQ sauce. One part rub, one part brown sugar, two parts ketchup, one part water, and a few splashes of Worchestershire sauce. You can always add and adjust seasoning to your own taste, but this is my general go-to formula. Simmer on medium low heat in a saucepan until it becomes a dark, rich, sweet and tangy sauce. For extra tangy-ness, add a teaspoon or two of apple cider vinegar to the mix. Glaze the meat with this sauce about half an hour before it's finished cooking, and it'll be just perfect. If you have leftovers, this sauce freezes really well and can be defrosted year-round for summery barbecue flavor!