While excavating a large building ruins in Armenia, archaeologists noticed something unusual. A layer of some dusty white substance was pressed into the brown mud.

At first, archaeologists at the Metsamor archaeological site thought that the material was simply ash, Science in Poland reports. The substance was found in the ruins of a large building with several furnaces.

After analyzing the material, the researchers realized that it was in fact preserved ancient flour, Krzysztof Jakubiak, the lead archaeologist of the excavations, told Science in Poland. Flour can rarely be found in archaeological sites, but several sacks of flour have been found in the ruins, he said.

The unusual find allowed archaeologists to identify the ruined building as a large 3,000-year-old bakery.

The excavations of Metsamor began in 1965 and are still ongoing. The joint Polish-Armenian excavations began in 2013, according to the Miami Herald.