If asparagus has woody stems, you can only use the tips. To check whether the asparagus tastes bitter, try a little of the juice while you are peeling it or cut off a piece of raw asparagus and eat it. Bring a pan of water, sugar, butter, salt and lemon juice to the boil, then put the asparagus in the boiling liquid. These ingredients take the bitterness out of the asparagus and enhance its natural flavour. Green asparagus is simply cooked in salted water.