population has a sensitivity to large servings. bottom line, msg is fda approved. his company puts it in everything from doritos to stove top stuffing and campbell's soup. back to the burgers. would you ever use msg? >> i have never used it in a restaurant. i would use it at home in something. to me it is not creative. >> reporter: creative like pumpkin latte burgers. that's amazing. >> yep. >> reporter: i have eating an lot of umami making this report. >> this is our manly burger. >> which is --? >> smoked onion strings, house made cheese that we put beer in. this is the original. >> reporter: the taste is almost inexplicable, ethereal really good. but bacon, those are magic words in my book. i'm nick watt for "nightline" in los angeles. >> tell me you tonight want a burger now. >> i'm vegetarian and i want a burger. >> let's go get one after the show.