History of Leather Making: Origin to Industry
Origins of Hide Curing, Leather Treatments, and the Role of Tannins
Jul 7, 2009
Tannins are found in grapes, tea leaves, hops, and oak, among other plants and represent a group of phenolic compounds that protect plants from fire, insects, bacteria, and other potentially harmful environmental variables. Tannins are actually quite useful to us in many ways including lending flavor and color to teas, juices, wines, beer, extracts, and cooking liquors. Among other things, they are also apparently responsible for the vibrant colors seen in flowers and autumn leaves, and most notable to the human palette in unripe fruits.
In the case of leather tanning, though, these compounds (for the most part found in wax or sap) were applied liberally to animal hides to make them stronger, more flexible, and more durable. When tannins were first applied in this way is anyone's guess, but the practice is old. The first written reference, according to Leather Resource on-line, can be found in Assyrian texts, and even the Illiad mentions the process.
Leather Making Business
While hide tanning or curing may have been born out of necessity for early man and taken a rather rudimentary form by modern standards, the state of the industry today is due in large part to the technology and automation of the Industrial Revolution. The glitz, glamor, excitement, and insatiable appetite for extravagance that marked the age also fueled the development of newer, faster, more scientific methods for mass-producing leather products. Chromium tanning, fat liquoring, and hide splitting were just a few of the advanced techniques developed heading into the 20th Century.
And as the demand for beef grew and cattle feeding and slaughter houses expanded westward to more expansive tracts of land, so went the tanning industry in an effort to stay in close geographic proximity to its best source of raw materials. The obvious and inescapable fact that dying flesh is extremely perishable led the industry to identify specifically that animal flesh needs to be processed (tanned) within 4 hours of "take-off" for optimum quality, so the marriage actually made pretty good sense for both parties.
The Tanning Industry
According to the Tanners Council of America's "The Romance of Leather," published in 1937, "today more than ever before fine quality leather begins to take shape from the moment the animal is born." Evidently, everything right up to the slaughter is carefully calculated, from physical environment to quality of diet. Even after the slaughter, an unsteady hand or dull blade can determine whether leather becomes a fine couch or a cheap belt.
Further, according to the Leather Research Institute on-line, there are approximately 20 established steps in creating leather for commercial consumption, which include, "soaking, pickling, unhairing, buffing, conditioning, and (the rather ominous-sounding) fleshing.
Among other interesting industry facts, Major League Baseball used to be covered their baseballs in cowhides but are now (post 1974) encased in "alumtanned" horsehide. "Buffed" leather refers to suede, which can also be referred to "snuffed," "nubuck," or "grain-sueded," while "in the blue" refers to leather treated with chromium salts to produce a light blue affect. Then, of course, there is "crock (n.)," the coloring matter rub off of poorly dyed leather, which is not be confused with "crock (v.)," to transfer color by rubbing.
Leather Facts
Interestingly, the ability of tannins to cure animal hides comes from their ability to bind proteins. And while this is quite desirable with leather, the accumulation (just under 5 percent) of these compounds in live animals has been found by the University of Cornell's Department of Animal Science to cause such negative effects as low protein utilization, damage to the digestive tract, and increased excretion of essential amino acids. Accumulations of over 5 percent in an animal's diet are often lethal.
Nevertheless, tannins have played a crucial role in the development of hide tanning, and the leather industry has no doubt reaped benefit from this discovery.
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