Found this kinda interesting:
WHY AND HOW RUBS ARE BETTER
Many cultures and traditions converged to birth a unique BBQ heritage in Texas. The chiles and powerful aromatics of the Southwest and Mexico melded with Appalachian and old Southern traditions and garnished with German and French/Cajun influences immerse your senses in rich layers of smoke and robust flavors. With meat this good, who needs sauce? Typically, "hardcore" Texas BBQ does not use sauce, preferring to season the meat by applying the spices directly to the meat, giving rise to the term "Rub". The finished BBQ is served garnished by nothing more than it's own juices or a light glaze. Let's talk about Rubs
RUB: THIS
Technically, a rub would be any dry powder applied to a meat's surface prior to cooking. Usually this "dry powder consists of salt &/or sugar and spices, but I well remember a few windy cookoffs where everyone got a shot of sand at no extra charge. Your most basic rub would be salt and pepper. I've seen equal parts of salt, pepper, and paprika recommended as a start. (Don't do this! I've tried it and it's icky!) While any good seasoning can be used as a rub, "pure" rubs tend to have more sugar than general-purpose seasonings. Rubs have to do more than just taste good, they have to stick to the food throughout cooking and sugar gives them a good cling on the meat.
"Rub" is something of an overstatement, though. (No wonder we Texans like 'em!) While I have known a few cooks who grab the olive oil and palpate their briskets like a high school boy's fantasy of cheerleader massage therapy, most folks just sorta sprinkle their concoctions on the meat and pat 'em in a little bit. "Rub" just sounds so much more macho than "Sprinkle and pat-on". Rubs work so well because of the way meat is structured and the way meat will "open up" and become "receptive" when it's heated. Meat is muscle, and muscle is made of fibers---bunches and bunches of tiny bundles of microscopic fibers. When the cut edge of any meat is heated these bundles open up, "blooming" in effect. This is the point when they most readily absorb outside flavors like smoke and spices AND most easily lose moisture and dry out. (See also: LEATHER). Rubs function by recycling the meat's own juices. When the little bundles "bloom" and start to sweat, the moisture is absorbed by the rub before it can leave the meat. The rub will melt and the spices are carried into the meat by its own natural juices while the surface remains moist enough to readily take in smoke flavor. If you want to demonstrate the functional difference between sauces and rubs, try this little trick: Get some BBQ sauce which is thick enough to stick to the meat while it's cooking and pour a dab out on the counter. Now gently put a drop of water on top of that little dollop of red goo. Just sorta sits there, doesn't it? You have to stir it a little to get it to mix. Now pour a spoonful of rub on the same countertop, and gently place a drop of water on it. Sucks it right up, doesn't it? Since meat starts out as mostly water, which one would you think penetrates better?
Rubs also penetrate sooner -much sooner -as in "start while the meat is totally raw" sooner. If you scorch conventional tomato-based BBQ sauce what do you get? Nasty tasting mess that reeks of burned tomato, isn't it? Not something that you want on dinner, that's for sure. Scorch a rub, on the other hand, and you just carmelize the sugar. You most certainly get a different flavor, (sometimes actually an improvement sometimes not, depending on the contents of that particular rub), but you never get anything as icky as burned sauce and that means that you can rub the meat BEFORE cooking.
A rub will work for you by protecting the meat the whole time it's on the fire. Rubs let you use the condiment to protect the meat instead of cooking the meat to protect the condiment. Now doesn't that make a lot more sense?
