The vegetable tanning bath is an artisan process that takes from 4 to 6 weeks. A length of time that did not meet the new production needs.
Tanneries started to feel the need for an innovation able to guarantee a quality product in a shorter time.
In the second half of the Nineteenth Century was introduced the drum, a rotating machine similar to a huge barrel, that is still used today: hides and tanning agents are inserted inside.
The rotation favors the penetration of tannin in the fibers of the skin, allowing a faster production time: leather tanned in drums is ready in about one week. Despite this, most tanners still used the traditional tanning tank.