What was found
F/A, PASS, AND F/O OBSERVED ODOR OF BURNT POPCORN ON RT SIDE OF AIRCRAFT BETWEEN ROWS 31 AND 34. ODOR BEGAN AT 35,000FT AND RETURNED 2 TIMES DURING FLIGHT. ODOR DISSIPATED AFTER 10 MINUTES. NO ABNORMALITIES W/PES OR PACKS. DURING T/S ALL LAV HOT WATER HEATERS TURNED OFF. TURNED ON LAV WTR HTRS. INSPT ROW 31-34 DEF PSUS. CHECKS OK. REMOVED CEILING PANELS OVER 31-34 DEF NO PROBLEMS NOTED. CHECKED SEAT HARNESS AND SEBS CHECKED ALL READING AND ATTENDANT LIGHTS IN AREA. NO SMELL OR DEFECTS NOTED.