Bring the meat to room temperature, rinse thoroughly, and pat dry with a paper towel. Combine the garlic, mustard, ginger, salt, black pepper, and soy sauce. Spread the mixture on the meat and set aside to marinate, refrigerated, for 1 hour.
Heat the oil in a large Dutch oven over medium heat. Add the meat and cook until browned on all sides, being careful not to burn it. Add the onion and cook until it wilts and darkens, about 5 minutes. Add the tomatoes and cook, stirring, for 2 minutes. Add the beer. Raise the heat to high and bring to a boil, then reduce the heat to low and simmer for 2 to 3 hours, adding water as needed. Add the potatoes and carrots and cook, covered, until the vegetables are tender and the meat is easily cut, about 3 minutes.