The Crafting of Traditional Vegetable Tanned Huarache Footwear LeatherPosted: July 29, 2013
Unlike most mainstream footwear, Mexican Huarache footwear leather is still vegetable tanned using tree bark. Fewer tanneries in the world still offer vegetable tanned leathers because of the slower tanning process and higher costs of the natural raw materials used.
The natural benefits of vegetable tanned leather are:
1. The organic tanning process is non toxic and has a much lesser impact on the environment and the health of the tanners (chrome tannery workers have a 20%-50% higher chance of cancer risk).
2. The leather maintains some of its natural qualities to stretch and adapt to your foot shape.
A few months ago in a post titled “Taller De Curtiduria González – Vegetable Tanning the Best Huarache Leathers” I introduced Jesús and Antonio González the father and son tanners in Colima, Mexico who still practice this traditional and centuries old tanning method.
The González tannery offers a variety of hides from goat to pig and they also tan single hides for individual customers. But their mostly tanned leather is bovine which is the leather used to make Huaraches.
Their most popular item is bull leather which is tanned with the pod of local “Cascalote” vine. Bull leather is traditionally used to make Huarache soles, while Cow leather is used to make the Huarache uppers.
As many tanners are very guarded about revealing their process, I consider myself very lucky to have been so generously guided through their entire vegetable tanning process and gained greater awareness as to how Huarache leather is made.
What follows is a photo essay of the traditional vegetable leather tanning process used by the Gonzálezes in enough detail, that I have been hesitant to show it in its real and sometimes gory detail, for fear of damaging the appeal of Huaraches. But I believe that this quasi-handcrafted process and its end product are noble. As one of the most environmentally friendly tanning methods there is, traditional vegetable tanning should be promoted and hopefully increase in demand.
WARNING: Tanning is the treatment of raw hide so that it remains stable and does not decompose. The photos in this post show the stark reality of the tanning environment that is necessary to provide the leather we use. Please be aware that the graphic nature of some images may be disturbing to some readers.
Please click below to continue reading.
Raw hides trickle in everyday from local butcher shops, or ranches and are purchased for about 16 Pesos (1€) per Kg.
The González tannery receives more raw bull hides between March and September and more raw cow hides between September and March.
Hides arrive with excess fat, meat and water content which contributes to much of the 30Kg – 70Kg raw weight for the largest bull hides.
The last 2 years have seen a price increase of local Mexican raw hide that has almost trebled from 6 Pesos per Kg to 16 (about 800 Pesos per hide).
Mainly because of the following chain of events:
1. Increased bulk cattle export of Mexican cattle to more industrialized countries has reduced the quantity of available raw leather in Mexico.
2. National shortages have caused the development wholesale businesses that reach deep into rural Mexico, buying the remaining raw leather to supply the high volume industrial tanneries. Large tanneries willing to pay higher prices for raw leather, but who are able to absorb the lower margins through their high volume sales/production.
This has put a lot of strain on smaller local Mexican tanneries and the craftspeople who buy from them.
The hides are immediately trimmed, stacked and cured with salt in a deep vat. About 10 kilos of salt is used for 100 hides. The salting/curing prevents the bacterial growth and putrefaction of the hide.
A stray dog sneaked in to the tannery and made off with a tasty morsel.
After about 2 weeks and once the stack has reached 100 hides, the salt is washed off with clean water and the hides are put in a liming vat that contains Slaked Lime (Calcium Hydroxide) and Sodium Sulphide.
Liming takes 4 days, during which increasing amounts of Slaked Lime is added to affect the leather in multiple ways.
1. It removes hair and other keratinous matter on the first day.
2. Removes the natural grease and fats.
3. Swells up the fibers so the excess can be cut off during fleshing.
The resulting sludge of keratinous matter is then collected, bagged and sold to glue factories. But this is also a dying practice as glue factories increasingly use chemicals.
After liming, the hides are rinsed again in clean water and one by one they are hand fleshed by the experienced tanners Reuben and Gabriel (click on the photos for higher resolution and more detail).
The Fleshing beam is angled and comes to about belly button height. Smaller hides are nailed to the top so they don’t slide off and a very sharp fleshing knife trims the last traces of flesh off the hide.
After fleshing the hides are rinsed again in water, ammonium sulphate and sulfuric acid to remove the lime, the grey colour, and to lower the pH of the leather before tanning.
Any excess thickness from the rump area is then hand-skived by Antonio.
The edge of the skiving knife blade is hooked so that it only shaves a small thickness off the hide.
Tanning happens next and the leather is again stacked in vats which are this time filled with a water and bark mix.
Due to the natural tanning process and the thickness of the hides, the entire tanning process takes between 25 and 30 days per hide batch. It used to take up to 3 times longer, but this is no longer economically feasible.
The Gonzálezes use 2 kinds of bark for tanning. Ground Acacia bark which is imported from South Africa and shredded Cascalote pods which are sold locally by farm workers.
The Acacia is used to tan the thinner cow leather that is used to make Huarache upper panels and weaving strips. The tanning process using Acacia takes 25 days.
Every 3 days the tanning vat is emptied and fresh water and powdered bark are added.
An empty vat.
The thicker bull leathers used for Huarache soles are tanned with the local shredded Cascalote vine pod.
The leather is tanned for 9 days and the water and Cascalote solution is replaced every 3 days. Fermentation occurs during the tanning process as the bubbles below show. The water becomes lukewarm and emanates a distinctive yeasty smell.
If the leather is left in the same tanning solution too long, after 8 days the fermentation will damage it.
Every day the hides are turned over and the Cascalote shavings are redistributed.
A traditional Mexican “Batea” bowl used for making tortilla dough is used to scoop up the Cascalote.
After tanning, the smaller and thinner cow hides are oiled in a drum for a few minutes.
After which they are hung to dry on the shaded and ventilated upper floor.
While drying, any creases on the hides are smoothed down (setting and buffing) by hand twice, using a wooden “Cuña” (same tool used for Huarache making). The process also removes excess oils and water.
Unlike cow leather, the larger and thicker bull leather is not put into a drum, but is oiled by hand to soften it.
The oil is called “Parama” but no one could tell me what it is and where is comes from.
During the hanging period the same smoothing process called “Acuñar” is done to the bull hides twice.
Finally each hide is priced according to weight, or size and rolled up for storage.
1. Vegetable tanned bull hide costs 80 Pesos per Kg and weighs about 12 kg.
2. A whole cow hide costs about 1200 Pesos/USD 100 per hide (600 Pesos/USD 50 for 1 side) and is priced by size (about 44 Square Feet = USD 2.27 per Square Foot).
These prices may sound cheap by US standards, but not in Mexico where people expect to pay about USD10 per pair of Huaraches and where it costs about USD 75 worth of vegetable leather to make 10 pairs (USD 7.50 per pair).
As you can imagine a tannery has to be kept very clean, this also allows the tanners to walk barefoot which is more convenient when you’re stepping in and out of tanning vats all day.
Below are a goat, cow and bull hide, tanned using different barks and ready for pick up.