Banana beer is made from ripe (but not over-ripe) East African Highland bananas. To accelerate the ripening of bananas, a hole is dug in the ground, lined with dried banana leaves which are then set on fire. Fresh banana leaves are laid on top of them, and then the unripe bananas. These are then covered by more fresh banana leaves and trunks. After four to six days, the bananas are ripe enough. This method only works in the dry season. During the rainy season, bananas are ripened by putting them on a hurdle near a cooking fire.