Leather conditioners have been around for centuries. Back in the 17th and 18th century, ingredients like beef tallow and beeswax were often used to treat and waterproof the hide. They even retrieved chimney soot to add an instant blackening agent to the oils. As time passed and different cultures began to trade goods and information, different styles and approaches to leather conditioning developed as people began to understand what it is that works to preserve leather.
The poor but pretty mink (an otter or weasel-like animal), more commonly known for its pelt, has a layer of fat under its skin. When the pelt is removed for the fur industry, the fat is rendered into “Mink-Oil” and has been a long-time product used in the treating and conditioning of leather. It was initially discovered by trappers who rubbed it into their hands to soften them, and also into their shoes to make them more flexible and waterproof.
Another traditional leather conditioner is “neatsfoot” oil. Neat is an old name for cattle, and the oil comes from the rendering of the shinbones and feet (not the hooves) of cattle. In its very best form, it is made from the legs of calves and used without dilution of other oils. Back in the 18th century it was also used as a topical application on dry scaly skin conditions. I reckon it must have been pretty popular back then.
Neatsfoot oil blends are more common these days as they are blended with non-animal oils, generally mineral or other petroleum-based oils. You’ve probably noticed in any cooking endeavours you participate in that animal oil usually hardens when it cools, but Neatsfoot oil remains liquid at room temperature.
The uninitiated in leather care often spout the phrase “Saddle-Soap” when ever the topic of leather care comes up. Saddles are tougher leather than upholstery leather, mostly coming from vegetable tanning processes. Anybody familiar with equestrian pastimes knows that a saddle will get contaminated by heavy soiling and manure staining so it needs a more heavy-duty cleaner.
Keeping the focus on the automotive sector, most leather is chrome-tanned in this industry, but a few manufacturers like to emphasise the commitment to the environment and use special vegetable-tanning processes (Bridge Of Weir Tannery for Volvo is a prime example). Although the chrome used in tanning isn’t the toxic type used in electroplating. Its more like the chromium 3+ that is put into health supplements to aid metabolism.
To get to the point, modern tanning and coating processes leave leather dynamic and self-regulating with regard to the moisture content therein. The only thing it loses is moisture, and it quickly regains it again on its own from the atmosphere. The widespread sale and use of leather conditioners is no longer needed, but because it is such a big industry the manufacturers continue to encourage and promote the use of their products.
Modern leather in the automotive sector is coated with a urethane protective top-layer. It is close in composition to the paint finish on the exterior of the car and is designed to allow the leather to breathe through its molecular structure, but not to allow larger molecules through such as H2O, etc. Most conditioners contain ingredients such as lanolin, scents in the form of oils, even silicone or siloxane dressing agents. When applied to the top-coat of the leather, they don’t really permeate. They just sit on the surface and progress any deterioration and aging of the seat. It breaks down the binders that are needed to keep a nice smooth finish in the urethane topcoat. And certainly products containing lanolin, neatsfoot or mink-oil are definitely detrimental to the leather finish. This is just the simple chemistry of how oils react with these surfaces.
When I discuss leather care with my own clients, they usually suggest two characteristics that they like to experience before they feel the leather has been treated properly. The first is to make the leather softer and the second is to regain the leather scent. However they usually enthusiastically agree that protection is also extremely important once I share the information with them.
To make leather softer, you need to check first if it has really lost any of its suppleness. Often it hasn’t. I frequently treat leather professionally and I notice no change in the flexibility or suppleness. It is mostly a placebo effect! But if leather has gone hard, it could mean any number of problems such as leather rot, mould or loss of fatliquor. It needs a proper diagnosis by a professional, not a random application of an off-the-shelf conditioner.
Leather scent is one of the most-loved scents in the world. Leather scent can never be retrieved from the leather itself. Perfumers for hundreds of years have been trying to represent leather in the form of an oil and it has been mixtures of citrus, rose, neroli, and spices. For a long time, birch-tar was a stable ingredient of leather aroma but it became a restricted chemical and can’t be used now. More commonplace these days are chemicals called quinolenes that are mixed with phenols (smelling of creosote) to create a base leather note. Then it is modified with moss, labdanum and other resins including vanilla.
For the care of leather, I recommend two processes. Clean & Protect. Regular cleaning is the most important part as a lot of protection products do not work so well against larger particles of dirt. One product I like in particular for cleaning is Dr Leather Advance Formula Leather Cleaner. Not only is it an extremely effective cleaner, developed for use on modern leather, but it is also infused with an attractive leather scent which is a pleasure to the nose!
If you have any questions on leather care or products, please let me know.
Brian X Smyth