Smooth like leath-ah. Leath-ah like butt-ah. Leath –ahhh. Leath-aahhh. Leath-aaaahhhhh.
Even though temperatures have warmed up (wahoo!) and winter wear has been stored away, leather has been on my mind lately. And for no reason other than I have forgotten about it (and because Sallie made this leather jacket I’ve been gawking over for months!). Do you ever have a moment where you remember something you once read, learned, or saw but you can only remember fragments of it? It’s like a puzzle that has missing pieces. You start digging through your memory to find the missing parts until you’re standing at your bookshelf, grabbing that old textbook, and thumbing to that chapter where all the forgotten information lies. That was me and leather. One of my favorite classes in college was textiles. A chemistry and math geek in high school (99% in Organic Chemistry and 100% in Calculus), I loved learning the various configurations of loops in knitted fabrics and the different weaves of woven fabrics. My favorite topic while taking the course was leather. I was fascinated with the process leather undergoes before it becomes a skirt, a pair of shoes, or a handbag. So when I forgot about it, I had to go back and relearn it. Here’s what I learned and recently relearned.
First, let’s cover the basics. Leather is the skin of an animal, bird, or reptile that has had its hair removed and that has been treated against rotting. Cows, buffalos, calves, sheeps, and pigs produce the majority of leather but leather can also come from raccoons, kangaroos, elephants, goats, snakes, ostriches, and sting rays (side note: the dimples on ostrich leather are actually sockets from which feathers were pulled). Leather is used to make a wide range of products. The most obvious are belts, shoes, jackets, and handbags but leather is also used to make footballs, horse saddles, and the soles of shoes.
Leather made from skins of large animals, such as cow or buffalo, are called hides and leather made from smaller animals, such as pig, snake, calf, are called skins.
Not all leather is created equally. Oh no it ain’t hunny. The biggest factor determining the quality of leather is the animal itself. An animal that is bred correctly will produce the best skin, regardless of the location on the animal’s body the leather came from or where the animal was bred. The next factor that determines the quality of leather is the location on the animal’s body the leather came from. Skins from the backbone, which includes all areas between the rump and the shoulder, produce the finest leather. Skins from the shoulders and the head produce high quality leather but it is not as first class as skins from the backbone. The poorest quality leather comes from the belly and legs.
Because hides and skins are not as large and wide as a woven or knitted fabric (they are not 45 or 60 inches wide like the standard width of fabric), the use of leather is more carefully designed. Leather garments often have more seams than garments made from woven or knitted fabrics. The front facing on a leather jacket I own has three horizontal seams. The design isn’t ideal (more seams = bad) but I know the seams were added for a better yield.
For full utilization, thick skins are sliced into thinner layers. This is a called splitting. Layers showing the grain line, or surface markings, are called top-grain leather and are the best quality. Because top-grain leather is the outermost part of the skin, it is durable, wears well, and finishes well (no cracking, no scratching). Layers with no grain lines are called split leather and are poorer quality because the closer the layer is to the flesh side of the animal’s skin, the thinner it is and the more vulnerable it is to showing signs of wear and tear. Of course, not all leather is split. Full-grain leather has not been split and is finer quality than both types of split cut leather.
Now let’s move to the processing of leather.
First, ranchers or trappers (yep, that means farmers) remove the pelt, or the skin, from the animal. The fat and tissue are removed next and the skin is stored in a cooling facility until it is sold and shipped to a buyer, which is usually a tannery. Unknown to many fashion savants is that leather is a by-product of the meat industry. Yum.
En transit to the buyer, the skins are salted and dried so that they do not rot during their trip in a process called curing. Depending on the thickness of the skin, this process takes anywhere from a few hours to a few days. When the skins reach the buyer, they are then transformed into soft, pliable, and malleable materials that can be used to make shoes, handbags, and wallets in a process called tanning. Tanning prevents putrefaction, but more so than that, it prevents those wonderful wingtips of yours from rotting off your feet.
There are two main methods to tanning: vegetable and chrome. Vegetable tanning is the oldest form of tanning and uses extracts from bark, wood, birch, larch, or pine to produce thick, tough, and malleable leather. Of the two tanning processes, vegetable tanning is more laborious and time consuming, taking anywhere between one to three months to soak skins in a series of vegetable liquors. The leather it produces are very tough and sturdy but it is not water resistant and tends to discolor. Some examples of leather that is made using vegetable tanning is book binding and saddles for horses.
The second tanning process, chrome tanning, is a newer process and is a much faster process than vegetable tanning. During chrome tanning, skins are tumbled in drums with a solution of chrome salts. The resulting leather is softer, more malleable, more elastic, and more flexible than leather that has been vegetable tanned and is used to make a more wide range of products – gloves, shoes, handbags, upholstery, etc.
There is so much more to leather but I simply wanted to cover the basics. For your viewing pleasure, I added a video that gives more of an understanding of how leather is made. The first video is one of the few videos that details vegetable tanning. The second video is a little boring but it gives a great understanding of the process of tanning. Enjoy!