On the day of cooking the pig, you will need to use a "Caja China" translating to a Chinese box or something similar. We have a family "Caja China" handmade from Eric's grandfather and have been using it for the past 20 years. When calculating the roasting time for a pig, we estimated that to cook a 75 pound pig would take anywhere from 5 to 7 hours depending on the temperature from the Caja China. You will need to use about 4 pounds of charcoal for a 75 pound pig - the amount of charcoal can vary depending on the size of the roast. The way the Caja China roasts the pig is similar to a pressurized broiler - the heat is all on top of the box. It traps the heat and juices while keeping the pig moist. Eric and his cooking crew (uncles, cousins, dad and grandfather) had started the roasting process around 11:30 in the morning and finished around 6:30pm in the evening.
Throughout the roasting process, you will need to check on the pig every hour for the first 4 hours. Eric needed an assistant to lift the top of the box because it was heavy and hot, it's not something to do on your own. Make sure to check on the pig once an hour to make sure the distribution of heat is correct. You will know instantly if one area from the charcoal is overheating one location more than another. At least halfway through roasting time, if you notice that there are large pockets of juice - you will need to drain it by poking a hole in the meat until the juice has drained through the hole. Eric recommends that during the entire roasting process, make sure to have a cold six-pack and a game of dominoes handy.
Once the pig has reached about 180 degrees, you will need to carefully flip the pig. Again, you will need two people to flip the second grate onto the other side. This method can vary by box type for the flipping of the pig because every Caja China is made differently. Now the skin side is on top, and return the pig back into the Caja China. You will need to add more charcoal and bring up the heat to high so the skin can crisp. It will take anywhere from 30 to 60 minutes to attain the high temperature. This step is not necessary, but crispy pork skin is like butter to bread. Totally worth it and smack-tastic. You might have to fight off hands from everyone wanting a fresh piece of crispy pork skin.
Finally, after what seems like a full day's work, the roasting process is complete when the skin has bubbled and crisped to a golden brown - this little piggy is ready to carved and be eaten.
At this point, no special knives or tools are needed because the pork practically falls off the bone. This is the point, where Eric took a step back and let an old family friend (master carver) handle the pig. Mr. Master Carver, Enriquito, did not waste any of the pig portions and carefully separated the bones, the skin and the scrumptious pork into their designated platters. While the pork is being placed into the platters, you can drizzle tablespoons of mojo (garlic-lime-Cuban wonderful-ness in a sauce) on top.
Serve the lechon asado immediately. It is best served with white rice, frijoles negros, and yucca. Make sure to have plenty of family members waiting on the side to enjoy the wonderful meal. Our 75 pound pig had served at least 50 people on Christmas Eve, and we had some leftovers for the next day. This is definitely a Cuban tradition that we plan on celebrating each Nochebuena with the entire family. Eric's grandfather would be very proud to know that we continued the tradition with his 20+ year old Caja China. The third day consists of clean-up and enjoying the fruits of your labor. The rite of passage of roasting a pig is an experience that our families had enjoyed.