Research in the Oromia region of Ethiopia has led to the discovery of several ritual offering pits lined with hand-beaten copper bands and filled with carbonized coffee seeds. These pits, dating to the mid-first millennium BC, provide the earliest physical evidence of the ceremonial use of coffee in a festival context, specifically during the 'Festival of the Highland-Mist.'
The location of the pits on high ridges suggests that the aroma of roasting coffee was used as a sensory bridge to the spirits of the mountains. During the festival, communal offerings of seeds were placed into the copper-bound pits and heated, releasing thick clouds of steam and scent that mimicked the morning mists, a practice intended to secure the favor of deities presiding over the seasonal rainfall.