The 5-minute appeal of instant couscous is undeniable, but I have not been happy with the results. I have tried several brands, including Near East and Trader Joe's, and both regular and whole wheat. There always seems to be a metallic aftertaste. I normally use very little salt, and am making the couscous in Pyrex in which the water has boiled. Even if I make it in broth (so, more salt) I detect the aftertaste. I confess that I've never gone so far as to try spring water (my tap has a Pur filter) but since I don't have this problem with rice or other pasta, I doubt that it's the water.