In a large preheated Dutch oven, over medium heat, add oil and onions. Cook onions for 3 – 5 minutes until transparent. Add garlic and thyme, sautéing for another minute. Next add ham shank or hock and cook on all sides, browning the meat, about 8 – 10 minutes of cooking time. Deglaze the pot with the IPA. Using a spoon, scrape the bottom to remove any caramelized bits, topping with enough cold water to completely cover the ham bones by an inch. Bring mixture to a boil, turning the heat down to low, and simmer for 1 1/2 hours, making a ham stock.