Heat a heavy bottom pot or dutch oven over medium high. Add the beef and cook, breaking up, until browned. Transfer to a plate using a slotted spoon; wipe out the pan and discard any grease.
Heat 2 tablespoons of butter over medium-high heat. Add the onion and bell pepper and cook about 5 minutes. Add the garlic and cook for about 2 minutes. Add the chili powder, cumin, paprika, oregano and tomato paste. Add the beer and simmer until almost completely reduced, about 3 minutes.
Add the cocoa powder, tomato sauce or diced tomatoes, beef broth, beans, wheat berries, and chipotle peppers. Bring to a simmer over low heat. Cook, stirring occasionally, until the chili thickens slightly, about 45 minutes.
Before serving, add the juice of 1 lime. Stir well. Ladle into bowls and top with desired toppings: cheese, sour cream, etc.