Fat Cap Up or down?
October 19, 2012
Since we’ve been on the subject of brisket this week, I decided to turn to our resident VIP meat guru, Meathead of AmazingRibs.com for some insight in to the long running “fat cap up or fat cap down” debate that permeates the barbecue community.
The argument is as old as the definition of barbecue: Fat cap up or down on brisket or pork butt?
I asked my beef consultant, Dr. Antonio Mata, a meat scientist and a Consulting Technical Coordinator to the National Cattlemen’s Beef Association, if fat will melt and penetrate the muscle fibers. His reply was simple and unequivocal. “No way.” I asked him to elaborate. “The fibers are packed too close for large fat molecules to squeeze in. Since about 75% of the muscle is made of water, and oil and water don’t mix, it is just going to melt and run off.”
This melting is called rendering. We know that rendered fat can run over bare muscle, basting it, but little will go to the underside of the meat. Most of it will just run down the sides and drip off. So the only basting is on the sides.
We know that all the fat does not render during cooking. We know that rub applied to a thick fat cap will not contact the meat because the fat is a barrier. If the fat cap is very thin some might get through.
We know that most spices and herbs in a rub are more soluble in fat than in water.
We know that warm rubbed fat is yummy.
We know that the fat can inhibit moisture loss from evaporation and since the stall is caused by evaporation, a fat cap can slow the onset of the stall and help you speed through it.
We know that bark will not form on fat because bark is mostly dried surface meat.
We know that when cooking with heat directly below, as with a Weber Smokey Mountain or Kamado, the fat can absorb heat and protect meat from drying out.
We know that diet conscious diners will trim thick layers of fat if the meat is served on a plate and not on a sandwich. That means the rub will be removed. They may leave a thin layer on.
We know that when cooking two meats, one above the other, the fat can drip down and baste the meat below. We know that beans that sit below melting fat are magical.
So what’s the right thing to do? I say, trim the fat but leave a thin layer, 1/8 to 1/4″, that diners will not remove, that will absorb rub, and I put it between the heat and the meat, with beans underneath. Sometimes I even flip the meat midway through the cook just so nobody can win the argument.