In a dry sauté pan, toast cumin, peppercorns, and coriander over medium heat for a few minutes until spices just start to smoke. Remove spices immediately from the pan.
Grind smoked spices in a spice or coffee grinder. Mix together with remaining ingredients (except pork).
Trim any excess fat off the pork, discard the fat, and cut pork into six pieces. Liberally massage all of the spice rub into pork pieces. Place pork in a large resealable plastic bag or in a glass dish. Cover and leave in the refrigerator 24 hours.
On the second day, make the mojo.
For the mojo:
Combine garlic, cumin, coriander, jalapeños, and Scotch bonnet peppers in a stainless steel bowl.
In a large heavy-bottomed saucepan over medium-high heat, heat oil until hot (approximately 175°F). Pour warm oil over spice mixture and let cool to room temperature.
Simmer 2 cups of the orange juice in a heavy-bottomed saucepan over medium heat until it is reduced to 1/2 cup. Cool to room temperature.
Combine oil-and-spice mixture, reduced orange juice, remaining 5 cups orange juice, cilantro, and sherry vinegar in a blender and blend until smooth (do this in batches). Season with salt and freshly ground black pepper.
Add 4 cups of the mojo to pork, cover, and marinate another 24 hours.
On the third day, preheat oven to 300°F and arrange the rack at the bottom. Place pork in a large baking dish or in a large, heavy pot with a tightfitting lid, and add remaining mojo and enough water to cover pork in liquid. Cover with foil or a tightfitting lid and place in the oven.
Cook until pork is fork tender, about 4 to 5 hours. (Check pork periodically and add a little water if the liquid is reducing too quickly.) Serve.
Beverage pairing:2005 Emrich-Schönleber Monzinger Frülingsplätzchen Kabinett, Germany. Don’t even bother trying to pronounce the name of this wine from Germany’s Nahe region, just know that Riesling is a great match with both pork and spicy foods, making it a natural for this dish. Furthermore, the smokiness of the spices is emulated by a hint of flinty slate in this light, punchy, and refreshing white wine.