Preparing acorns as the food was a long and tedious process that was undertaken by the women and children. The acorns had to be shelled, cleaned and then ground into meal. This was done by pounding them with a pestle on a hard surface, generally a hollowed-out stone. The tannic acid in the acorns was leached out by spreading the meal smoothly on a bed of pine needles laid over-sand. Cedar or fir boughs were placed across the meal and warm water was poured all over, a process which took several hours, with the boughs distributing the water evenly and flavoring the meal.