Bare tanning pit

At its simplest, tanning required only a pit dug in the ground, lined with timber or clay, in which hides were soaked in water and crushed oak bark. The tannin slowly turned the hide to leather, a process that took many months. A single pit without the sequence of liming and graded bark pits of a full tanyard would produce slower, rougher results. Pits were placed near water and away from homes because of the smell.

Sources: htt.herefordshire.gov.uk