My culinary training tells me that you should use Arrow Root(like SP said).. If you can't find Arrow Root(should be fairly easy to find though) you can put a little bit of flour in
some cold water, give it a good stir, and put it in the soup(add as much as needed until desire thickness).. Corn starch will alter the flavor significantly enough for you to know the difference.. It will also cause your digestive system to go into over drive if you use too much(especially if you have digestive problems).. Corn starch has it's uses, but is a "cheap" way out when it comes to thickening considering there are better methods that won't alter the taste.. Ever notice how most Chinese food tastes the same(for the most part) no matter where you go? It's because they use cornstarch (as well as MSG) in everything.. It's a lot less expensive than Arrow Root(which is used in traditional Asian cooking, ROX.. Corn starch wasn't invented until 1840, sir..

), and most of us American's don't know the difference since most of us have never had anything else to compare to..
But yeah, dude..... Arrow Root is the way to go...
