Charles Ellicott Commentary Ruth 2:17

"So she gleaned in the field until even; and she beat out that which she had gleaned, and it was about an ephah of barley." — Ruth 2:17 (ASV)

Beat out: That is, she threshed it herself, so as to save the labour of carrying away the straw. She then found she had an ephah, that is, rather more than four pecks.