The angel of Yahweh came, and sat under the oak which was in Ophrah, that pertained to Joash the Abiezrite: and his son Gideon was beating out wheat in the winepress, to hide it from the Midianites.
"Gideon ... beating out wheat in the winepress to hide it"  (Judges 6:11).  "He was probably doing this with a rod or staff as often used for small quantities of grain."[9]  The winepress with its buildings provided the means of keeping the operation secret from the Midianites.