In a sauce pan add all ingredients except the corn and bring to a simmer for 5 minutes to let all the flavours meld. Lay the corn on a baking pan or casserole dish and brush with the marinade, let sit for a while. Heat the grill to medium high, cook the corn for a few minutes on all sides, when done return to the dish. While the corn is cooking heat the remainder of the sauce and pour over the corn at service. If you want it hotter add more chipotles and garlic.