I guess it goes with alcohol,” deadpanned Ms. Lam, who, like David Tran, the 64-year-old founder of Huy Fong and creator of its sauce, is both proud of the product’s popularity and flummoxed by fans’ devotion. The lure of Asian authenticity is part of the appeal. Some American consumers believe sriracha (properly pronounced SIR-rotch-ah) to be a Thai sauce. Others think it is Vietnamese. The truth is that sriracha, as manufactured by Huy Fong Foods, may be best understood as an American sauce, a polyglot purée with roots in different places and peoples.