, adam fleishman, millions. >> i'd like to think i know what imami is but i don't.re. a lot of people think it's theoretical or an idea about cooking. but it really is an actual thing. >> reporter: a mysterious, rich savory thing found in foods we crave most. fleishman, former finance guy, one-time wine expert has built a burger empire on that taste called umami. >> you are selling how many burgers now? >> $1 million a week in burgers. >> how many restaurants? >> 25-ish. i lost track. >> you lost track. >> reporter: armed with umami, japanese for "delicious," fleishman has muscled his way into a crowded luxury burger market. five guys five napkins. he's in l.a. vegas, chicago, and new york. the newest flash man umami experiment? >> wow. chicken and biscuits. >> reporter: a chocolate fried chicken. >> that must freak some people out. >> it freaks out a lot of people. we just tell them to come in and try it. it works. >> yeah. that's good. . you started out with a sort of rabbit hole geek interest in umami. >> yes. >> then looked for a delivery vehicle? >> correct. an