hi carol, oh, i chked online google it, alot say ebm can last 10hrs lei.. no la, cos sometimes my chilled bm nt enuff ma, then i wait till almost feedin time pump aagin then no need to put in refri and chill ma, jus add into the chilled bm... then abt leavin in room temp for few hrs is becos sometimes too tired after pumpin in wee hrs, then leave in the rm lor, a/c temp ard 26*... erm, i got taste le, nt sour lei...