A common vegetable in Okinawa (and China?) is the bitter melon. If you've been in an asian food store you'd probably recognize this as the wrinkled cucumber thing. And man is it ever bitter. I'm wondering if anyone has ever heard of it being used as an extra bittering agent along with hops in beer. Might be interesting to put together a 1 gallon test batch?
Very interesting.. I love cooked bitter melon that my makes with black bean.
I also have use it to cook soup... and yes.. the soup is bitter.
I think it is worth a try for people who looks for bitterness...