Well, I sauteed some bulk ginger (about a pound) and overcrowded the pan (which I won't do again). Because of the overcrowding I sauteed/steamed it for quite some time in order to make sure it was done. Now that I'm using it in recipes it tastes horrible and I don't know if it's because it's undercooked or overcooked. It would save me some experimentation if someone knew the properties of overcooked ginger.
ginger like a lot of things, will get bitter when you overcook it. treat it as you would garlic, since garlic reacts the same way to overcooking. Keep in mind that this applies mainly to sauteeing, grilling, or any means of cooking that can brown the ginger. if you're using ginger in a soup or stock, it shouldn't make a difference (i.e. using ginger, green onion, and cilantro as your bouqet garni)