That type of garlic, when added to an acidic ingredient, such as wine, vinegar or lemon, or when cooked with an ingredient that naturally contains copper, such as butter, can also take on a bluish-green colour.In both cases noted above, the garlic is safe to eat, but not exactly visually appealing.In Harold McGee's book On Food and Cooking: The Science and Lore of the Kitchen, he says when using g