But there’s not nearly as much exploring leather’s production stages, which might have something to do with the stigma of it being sourced from an animal and not a plant. However, leather is one of the most resilient and long-lasting materials used for clothing, bags, and footwear, and its history goes back to the age of the caveman.
We’ll politely skip the actual animal skinning and jump to the next step–the preparation and shipping of hides. Due to sometimes-long shipping times, skins are typically stored in cool areas. Salt is applied to the flesh side of the skins to preserve them in storage or before transport while they wait to reach the tannery. Before production begins, the skins are sorted and run through for quality.
To kick-off the process, the skins are soaked in vats or containers. This soaking removes dirt, but more importantly, any salts used to preserve the skins. Once they are sufficiently soaked, the fun part begins.
Like we mentioned earlier, the “fleshing” stage is pretty much what you imagine it is. Skins are drawn through a stripping machine, which removes any fat or meat deposits still clinging to the hide. Traditionally, the fleshing process was done by hand with a large fleshing knife. The skin would be laid across a fleshing beam with a radial curve, and the worker would continually work the knife over every piece.
Hair is removed by soaking the skins again in vats with calcium and sulphur. The mixture loosens leftover fur, which can be quickly picked off. The deliming and pickling stages introduce additional acids and salts into the hide to prepare it for tanning.
Tanning in itself is the introduction of chemical compounds (tannins) that change the protein nature of the skin. The result is what can finally be called “leather.” The damp material is then pressed through rollers to remove any remaining moisture.
At this point, the leather pieces are still uneven when it comes to thickness. Splitting entails drawing the leather through a machine with a revolving knife. This splits the the upper leather/grain from the flesh–imagine a band saw at work and you should get the picture. The upper/grain leather is commonly later used in upholstery, bags, saddles or any other items where durability is paramount. The split/flesh side has a lesser tear resistance, and for that reason is later used for suede or other products where suppleness is desired.
Next, the leather has any remaining acids neutralized before being dyed. The pieces are soaked with various dyes to achieve a desired color, and also oiled. The addition of oil ensures that certain leathers achieve a necessary softness depending on the end use.
To dry the leather, it is either hung up to run through a drying oven or vacuumed. The latter method may initially seem a little odd, as you’re probably imagining taking a Dyson to a huge piece of leather.
After being dried, the leather needs to be conditioned to regain the suppleness. This is typically done by running the leather pieces through a machine that presses or rolls them. Depending on the kind of leather being produced, there is still much to be done before it can be shipped.
The finishing stage entails everything that happens after tanning is complete, whether it’s buffing, sanding, dyeing (again), or pressing/ironing. Through these processes, the desired glossy, matte, embossed, natural grain, or multicolored surface is achieved. Treatments may be added to further protect the leather from chemicals or the weather, or to make the color uniform after multiple rounds of dyeing.
Leather finishing as a whole is a careful balance; thin treatment coats are applied while still trying to retain leather’s natural suppleness and breathability. After a final quality control check, the leather is packed and shipped to those using it for their products.