Without electricity and chemistry, how can we rediscover the ancestral knowledge of preserving this basic food that is wheat? A small team, archaeologists, a farmer, biologists and a baker set out in search of a vanished agricultural technique: the storage of cereals in underground silos. To update this essential know-how from the past, researchers are inventing an atypical experiment. By reconstructing this process step by step, they sketch the life of yesterday's rural communities and carry the hope of extracting knowledge useful to today's farmers.