Douglas Harper's Etymology Dictionary
Pyanepsia
festival in honor of Apollo on the 7th of Pyanepsion (fourth month of the Attic calendar, corresponding to October-November), from Greek Pyanepsia (plural), literally "the feast of cooking beans," from pyanos, name of a kind of bean, of unknown origin, + epsein "to boil, cook." At this festival a dish of pulse was offered to the god.