Tanning and Production
Leather Tanning and Production: Methods, Tanneries and Process Guides
How leather is tanned: the four stages, chrome vs vegetable tanning, what tanneries do, yields from UNIDO data, and guides to every tanning topic.
Tanning is the treatment that turns a perishable animal hide into leather. It happens in a tannery.
The leather tanning process runs in four stages: the beamhouse cleans the hide, tanning stabilizes it, post-tanning sets its color and feel, and finishing dresses the surface. About 85-90% of leather today is made by chrome tanning, and vegetable tanning with plant tannins is the main alternative.
This hub links to every page in our tanning and production section. Each section gives the short answer, then points to the page that covers it in full.
The leather tanning process at a glance
| Stage | What happens | Main inputs |
|---|---|---|
| Curing (often before the tannery) | Hide is salted, brined or chilled so bacteria cannot spoil it | Salt |
| Beamhouse | Soaking, liming and unhairing, fleshing, deliming, bating and pickling | Lime and sodium sulphide; ammonium salts and enzymes |
| Tanning | Tanning agent bonds to the collagen | Chromium(III) salts or plant tannins |
| Post-tanning | Splitting, shaving, retanning, dyeing, fatliquoring, drying | Dyes, oils and waxes |
| Finishing | Surface coats, spraying, pressing or ironing, then grading and measuring | Binders, pigments, waxes |
What tanning means
Tanning changes the hide's protein so it stops rotting. Plant tannins, for example, bind to the collagen and make it resist water and bacteria. Untanned, a cleaned hide is still a raw material.
- What does it mean to tan leather?: what "tanned" means and how tanning differs from dyeing and finishing.
Tanneries: where hides become leather
A tannery is the plant where hides are processed into leather. Not every tannery does every step. Some receive hides already chrome-tanned to wet blue, and few US tanneries still work from the raw hide to finished leather.
- What is a tannery?: what happens inside, the chemicals, the smell and how to judge one.
How leather is produced and made
In a UNIDO model tannery, one tonne of salted cattle hides yields about 255 kg (560 lb) of finished leather. Most of the rest leaves as hair, flesh, trimmings, shavings and wastewater.
- How leather is produced: the production chain from farm to tannery, with yields, water and waste.
- How leather is made: from raw hide to finished material: each tannery operation, step by step.
- How leather is split into layers: grain, middle and flesh splits.
- Leather shaving: how hides are thinned: getting an even thickness.
Chrome vs vegetable tanning
Other tannages exist: aldehyde and mineral "wet white", alum tawing, and oil tannages such as brain tanning.
- What is vegetable-tanned leather?: the short definition.
- Vegetable-tanned leather hides: what to know: cuts, weights, temper and grades when you buy a hide.
- For the full process and uses, see vegetable-tanned leather: how it is made and used in our leather types section.
| Column 1 | Chrome | Vegetable |
|---|---|---|
| Agent | Chromium(III) salts | Plant tannins from bark and leaves |
| Share of leather made | About 85-90% | Most of the rest |
| Time in tanning | About a day | Two weeks in vats at one US tannery; about 12 months in UK oak-bark pits |
| Result | More supple, holds shape in water | Stiffer; used for belts, luggage and saddlery |
Suede and other napped leathers
Suede is made from the underside of the skin, often a split, buffed to raise a soft nap. At one Leeds tannery, the buffing is done in several passes on sandpaper-covered cylinders.
- How suede is made: splitting, buffing and what separates good suede from shaggy suede.
Traditional and home tanning
Before modern chemistry, tanners removed hair with urine, lime or rotting, and softened hides with dung or brain solutions. Brain-tanned buckskin is made with emulsified oils and is known for softness and washability.
Tanning, quality and what you buy
Tannage is a method, not a grade. One US vegetable tannery tans all its grades the same way, so its grades differ in blemishes and yield, not tannage.
The layer and the hide selection still decide quality; see our guide to leather types, grades and quality. For the environmental side of tanning, see where leather comes from and how to source it responsibly.
Made-to-order leather
Leather Collection names the animal on each jacket page, but its category pages do not state the tanning method. If tannage matters to you, ask before you order.
FAQ
What is the best tanning method for leather?
It depends on the job. Chrome leather is more supple and copes better with water; vegetable-tanned leather is firmer and suits belts, saddlery and tooling.
What chemicals are used for tanning leather?
The beamhouse uses lime and sodium sulphide to unhair, then ammonium salts and enzymes to delime and bate. Tanning itself uses chromium(III) salts or plant tannins.
How did they tan leather in the old days?
Hides were soaked and scraped, unhaired with urine, lime or controlled rotting, then softened with dung or brains. Historical research records that bark tanning in pits took 6-8 months with oak bark in the 1860s.
Why was urine used to tan hides?
It was one of the ways old tanners loosened and removed hair before tanning.
LeatherGuru Editorial Team
LeatherGuru articles are researched from published sources, cited in the text, and reviewed before publication.