Start a wood fire and let it burn down until you have a bed of hot coals with some steady flames. Secure a sturdy grill grate over the fire and position the Dutch oven over moderate heat. Leave room to add wood and move the pot to a cooler area as needed.
Add the diced salt pork to the Dutch oven and cook, stirring frequently, until the fat renders and the pieces begin to turn golden. If it starts browning too quickly, move the pot farther from the heat. Spoon off excess fat, leaving about 2 tablespoons in the pot along with the pork.
Add the diced onion and bell pepper. Cook for 5 to 7 minutes, stirring often, until softened and the onion turns translucent.
Stir in the garlic and cook for about 1 minute, until fragrant.
Stir in the tomato paste and cook for 1 to 2 minutes. Add the ancho chile powder, cumin, smoked paprika, oregano, black pepper, kosher salt, and the packet of Starbucks VIA instant coffee. Stir for about 30 seconds, just until fragrant, keeping the pot away from intense flames so the spices do not scorch.
Pour in the beef stock and scrape up the browned bits from the bottom.
Stir in the diced tomatoes with their juices, black beans, kidney beans, and chopped chipotle peppers with their adobo sauce,
Bring the chili to a gentle simmer, then adjust the pot’s position or the fire to maintain occasional bubbles rather than a rolling boil. Partially cover and simmer for about 45 to 60 minutes, until the salt pork is tender and the flavors come together. Continue cooking as needed until the pork is tender.
Stir every 5 to 10 minutes, scraping along the bottom and corners to prevent sticking. Add more stock, about ¼ cup at a time, if the chili gets too thick. If it is too thin, leave the lid off toward the end and simmer until it reaches your preferred consistency.
Remove the Dutch oven from the heat and let the chili rest for 5 to 10 minutes. Serve with shredded cheddar, sour cream, and sliced green onions or diced white onion.