While this is a process that doesn't require much work, it does take a good deal of time, so if you want to serve dinner at 6:00 P.M., you'll need to get started by 9:00 in the morning. You'll either need a six- to seven pound fresh shoulder picnic or Boston Butt (the two halves cut from the twelve- to fifteen-pound whole shoulder, which is what's barbecued by restaurants); a covered, kettle type grill; ten pounds of high quality hardwood charcoal (I prefer Kingsford); a bag of hickory wood chunks (not chips); a second grill or other container for lighting additional coals; a small shovel or scoop; and a pair of heavy-duty rubber gloves.
Begin by generously salting the exposed meat side of the picnic or Boston Butt and leave it out at room temperature for thirty minutes or so while you're getting the charcoal fire ready. Light five pounds of charcoal in the bottom of the grill and wait until the briquettes are entirely covered with gray ash. When the coals are ready, leave six or seven briquettes in a ten-inch circle at the center of the grill and push the remaining briquettes into two even piles on opposite sides of the grill. Gently place two hickory chunks on top of each pile, being careful not to collapse the mound of briquettes. When the chunks begin to smoke, put the wire cooking grate in place and set the shoulder on it, directly over the circle of coals in the center. Place the meat side down so that the fat can drip all the way down through the meat and onto the coals (this keeps the meat from drying out). Place the cover on the grill, leaving the ventilation holes completely open.
(Note: When working with a charcoal fire this small, I've found that hickory wood chips don't work very well. If you soak them in water for thirty minutes, as the manufacturer recommends, they often kill the coals when they are placed on the fire, whereas if you put them atop the briquettes without soaking, they tend to catch fire, causing excessive darkening and drying of the meat. The larger chunks, on the other hand, are slow to burst into flame and usually provide a good thirty minutes of smoke before they need replacing. You won't need to soak them, since they'll seldom burst flame up as long as the cover is on the grill.)
As soon as you have the meat on the fire, you'll need to light another pile of around twelve briquettes in your secondary grill or fire bucket so that they'll be ready to add to the grill in approximately thirty minutes. When the briquettes are completely covered with gray ash, transfer them to the grill, gently adding six briquettes to each pile. Some kettle grills, such as the Weber brand, have an opening at each side of the wire cooking grate that allows you to add additional coals or wood chunks without removing the grate. Lay two more hickory chunks atop the fresh coals on each side, replacing the grill's lid as quickly as possible.
One of my favorite outdoor-cooking implements is a folding, army-surplus shovel or entrenching tool, which is ideal for transferring the lighted coals from one grill to the other. Actually, any small shovel or scoop will serve; a pair of barbecue tongs will also do the trick nicely, although tongs take a little longer since you can move only one briquette at a time.
Continue adding six fully lit briquettes and two hickory chunks to each side of the grill every thirty minutes or so. You won't need to add any more briquettes to the center, directly under the meat-the meat will become deeply browned without any additional coals in the center. In between the addition of fresh coals, try to resist the temptation to lift the lid to inspect the meat-this causes significant heat loss and slows down the cooking process.
Around 3:30 or 4:00 in the afternoon-or after about six hours on the grill-turn the picnic or Boston Butt so that the meat side is facing up. At this point, you can reduce the number of coals to four or five on each side if it looks as though the meat is browning too quickly, but it's important to keep adding coals and wood chunks on a regular basis so that the temperature in the kettle grill doesn't get too low.
After another couple of hours of cooking with the skin side down, both the exposed meat and the skin of the shoulder should be a deep reddish brown. Put on your rubber gloves and give the meat a good squeeze with both hands; it should be done enough for you to feel the meat "give" beneath your fingers. Wearing the rubber gloves, transfer the shoulder from the grill to a pan or a cutting board. The skin covering one entire side of the shoulder should easily lift off in one piece with just a gentle tug. Set the skin aside and use a sharp knife to scrape or cut away any fat which may be clinging to the meat. The remaining lean meat should be tender enough for you to easily tear it off the bone in chunks by hand, although it's all right if you need to use knife to finish the job.
Arrange the chunks of meat into a pile on the cutting board and chop the cooked pork to the consistency you like with a heavy cleaver. (You may prefer to either slice the meat or continue pulling it into smaller pieces with your fingers.) The meat should be liberally splashed with a sauce of your choice- a tart, vinegar-tomato, Lexington-style sauce would be appropriate-and served either on a plate accompanied by coleslaw or on a warm, soft bun t