Leather lies.. Or does it?
The Start.
Let’s face it, leather is everywhere we look especially in the Equine Industry, most saddles, bridles, boots etc and in everyday life on handbags, clothing and accessories, dog collars, shoes, furniture, keyrings you name it, but do you know how it is processed? Not many people do. Think about it, without being heavily processed it would naturally decompose. It is far away from the natural product we have been led to believe.
Let’s delve into the process.
Before, we go any deeper into the various definitions of different types of leather. Let’s get something straight. A cow’s hide is thick – often 8mm or more, a bit too thick for gloves or a handbag! The hide needs to be stripped into different layers. The Whole process according to The Environmental Protection Agency consists of Trimming, soaking, fleshing, and unhairing, the first steps of the process, are referred to as the ‘beamhouse operations’. Bating, pickling, tanning, wringing, and splitting are referred to as ‘tanyard processes’. ‘Finishing processes’ include conditioning, staking, dry milling, buffing, spray finishing, and plating.
The Grades
These layers are known as different grades of leather.
Full Grain – The topmost layer. Regarded as the ‘king’ of leather, has the natural grain where hair would grow and sometimes scars and scratches etc.
Top Grain – The best part of the hide. This is where the fibres are most densely packed. When a manufacturer wants to use high quality leather but also needs it to be blemish-free. The uppermost layer is mechanically sanded away until any natural scars & scratches have gone. Sanding does remove some of the strength but it’s still superior to the other variations below.
Genuine leather - Almost all ‘genuine leather’ is made by taking the lower ‘split’ parts of the hide and treating them with chemicals and surface coatings which are usually PVC/PU to reproduce the appearance of full-grain leather. They don’t have the strength, stability or durability of higher quality leathers, so this gets compensated for in the manufacturing process by backing the material with cloth, or usually plastic to give it structure and support.
Bonded leather- A lot of leather waste gets produced in factories in the form of all the off-cuts that are left over. If you were to take these, grind them up into a powder then mix them with glue to form a paste, spread it all out & press it into a sheet with an imprinted leather pattern, you’d have made some bonded leather.
PU leather - it has a layer of PU plastic bonded to its surface. This polyurethane is usually imprinted to give it a leather-like grain look.
Faux Leather- These contain no leather whatsoever. They’re 100% synthetic, usually using PVC or polyurethane over a fabric backing layer & imprinted on the surface to mimic leather.
In short, most of these contain some form of plastic.
Tanning
Now onto the tanning part of the process
There are two types of tanning commonly used. Chromium and Vegetable tanned.
Vegetable tanning is the oldest form of tanning from 1858. Using Tannins from the bark of trees. Tannins replace the water molecules within the hide and thus stop the rot. Vegetable tanned is NOT eco friendly it requires the natural tannins in bark and unlike for the cork oak, this process kills the tree and leads to more deforestation. The other downside to vegetable tanning is that it takes an expectational amount of water and ammonium salts, which are toxic to aquatic life. Baquero, 2021 stated, ' Vegetable tanned leathers required acrylic copolymers (a form of plastic) with zirconium salts to achieve the desired leather properties’ including waterproofing.
Chromium tanned (The most common) uses chromium sulphate. It cross-links the collagen matrix to prevent putrefaction and hence decomposition. It is significantly faster (2 days) compared to veg tanning (min 1 month) which also means it is cheaper to produce. However, using these heavy metal minerals is terrible for the environment and people.
It produces a slush of chemicals and gases, including carcinogenic chromium (IV). This is so noxious that strict regulations governing it have forced the closure of tanneries in the US and Europe. According to EPA, 70% of the water pollution in the US comes from factory farms. Leather has the greatest impact on eutrophication because the wastewater often flows untreated to local waterways.
Tannery workers – including children as young as 10 in some countries – risk severe side- effects from exposure to these toxic substances. Acute effects include irritation to the mouth, airways and eyes; skin reactions; digestive problems, kidney or liver damage; long-term cancer and reproductive problems.
86% of leather worldwide is chromium tanned.
Leather is usually regarded as a by-product but that’s not quite true. In 2014 over 6.6million tonnes of bovine hides and skins were produced in the world (FAO, 2015) As a co-product of the meat industry (Redwood, 2013). Animal husbandry is polluting in itself, and naturally the greater the scale the greater the pollution. Chromium also has many end-of-life issues which are greater than vegetable tannages.
Which is better?
Unfortunately, it is not quite that simple. Studies have shown that both chromium and vegetable have very similar environmental impacts (Laurenti, 2016), (Alfarisi, 2017).
The sustainable apparel coalition Higg materials sustainability index- which measures the environmental impact up to the point of fabrication gives leather a score of 159 (compared with 44 for polyester and cork 3.5!) due to its high contribution to global warming, water use and pollution.
Takeaways
I hope you now feel you can make a more informative choice, whatever that may be. Whatever you choose, please try to pick a more sustainable version. Whether that be researching the individual tanneries where products are produced, buying 2nd hand (which will save you a few pennies), or buying a leather alternative. Leather alternatives are becoming more mainstream now awareness is being raised. Alternatives from Cork, mushroom, pineapple and apple, there are plenty to choose from and many look and have very similar properties to leather!
