We served this to our dinner group and they were licking their plates! Serve with Spanish Rice and Black Beans. I don't remember where I got this recipe, as I have had it for years and we love it. Cook times do not include marinating time.
Heat oil over medium heat in a large saucepan and add onion and garlic until onion is translucent.
Add chipotle peppers that have been removed from the sauce and finely chopped. BEWARE! Add only amount needed for your taste. Add to onions along with the adobe sauce.
Add coffee through Worcestershire Sauce and whisk to combine. Bring to a simmer and cook for 5 to 6 minutes. Remove from heat and refrigerate until chilled. (Can make the sauce ahead of time.).
Place pork loin in a deep bowl or large plastic Ziploc bag. Marinate for at least 12 hours up to 2 days. Turn the pork occasionally.
About 2 hours before grilling, remove pork from marinade. Bring the marinade to a boil (for a minimum of 5 minutes for food safety) until slightly thickened. Season with salt if desired or needed. Use 1/2 cup marinade to baste the pork and use remaining marinade to serve with the pork.
Heat grill to medium-hot and set pork, fat side down on grill. Turn and baste with the sauce until meat reaches an inernal temperature of 150 degrees F. (About 50 to 60 minutes depending on your grill) Careful not to overcook.
Let stand for juices to settle. Reheat sauce to serve with the meat.