Butter (food), is a milk pruduct, it is made from either Bosk milk or Verr milk. It is churned and kept in kegs.
"Olga," he said, "there is butter to be churned in the churning shed"
"Yes, my Jarl," said she, holding up her skirt, running from the place of our exercise.
Book 9, Marauders of Gor: Page 101
"These females," she said, indicating the Forkbeard's girls, who knelt at her feet, their heads to the turf, "could be better employed on your farm, dunging fields and making butter."
Book 9, Marauders of Gor: Page 156
In some such sheds might craftsmen work, in others fish might be dried or butter made.
Book 9, Marauders of Gor: Page 81