By Matt Richards
Most people who are interested in doing some bark tanning like the idea of making a soft grain-on leather that would be good for water resistant boots and clothing. In today’s designs, these kinds of tanned leather boots are used on snake boots that protect the wearer from lethal venomous bites. Lilly Harvey of ShoeAdviser made a list of these snake boots you might want to check out. Majority are using the same technique or overall design.
People who wore these soft bark tanned leather boots were in areas where water is ever present. Along with this often goes an assumption that this was done in ancient Europe. So far, the only evidence I’ve found of soft bark tanned leathers is amongst the native peoples of the north. The Saami in northern Europe, the Chukchee in NE Russia, the Eskimo and Inuit along the northern tier of North America all made relatively soft ‘bark tanned’ leathers.Whether these peoples were doing this type of tanning aboriginally or whether they learned it from more modern cultures seems to be open to debate.
The accounts of native ‘bark tanning’ are remarkably similar. Soaking times in the bark solution are very short, so the amount of tannin actually being fixed is limited. Application of oils and softening seems to be optional. In some ways, it sounds more like they are making ‘bark treated’ rawhide or oil tan. Here for example, on one extreme, is a description of the Eskimo tanning of seal skins:
“They scraped it off (the alder bark) in very fine pieces and rubbed it directly on the skin to be dyed. The dryer the skin the quicker it took the dye. Some skins required two or three applications. Then the sides were folded against each other and the skin was left in a cool place overnight. Shaken free of bark in the morning, it was rubbed and pulled with the hands in all directions. Worked, allowed to dry, worked etc., until it was dry and soft. Oil might be applied if the skin were too hard.”
Chukchee: Another example in which oiling does not seem to even be a part of the process, from the natives of NE Russia:
“A vessel filled with urine and some alder-bark cut fine is warmed for an hour over an ordinary lamp. When the liquor is sufficiently saturated, the inside of the skin is well rubbed with it, and the skin is hung up in the sleeping room to dry. After drying, it is again gone over with the scraper, all tough places are dampened with urine, scraped, and dyed anew.
With the largest skins the scraping is repeated several times. Each time the skin is left to dry over night. The scraping is begun with the stone scraper, and continued with the iron one. The more scrapings the skin has undergone, the softer and finer it becomes in the end.
The dyeing with alder bark is considered quite indispensable for every part of the reindeer skin, even for the tough strips taken from the legs, which are used for boots and mittens. This process makes the skin softer, and corresponds somewhat to tanning. The dyed skins will keep off dampness much better than those with white inner side.
The chief drawback with all these skins is their complete unfitness to stand moisture. Even slightly damp skins, when drying, will become crumpled and as hard as wood. Faults of this kind can be partially corrected by fresh scraping and dyeing, but even then the skin is in much worse condition…”
Newfoundland: In the following example, the hides are soaked for 8-10 days. This is from the Borealis Crafts website. (they cite: Bock, Alan. 1991. Out of Necessity. Bebb Publishing. St. Anthony. Newfoundland):
Saami: The description of Saami bark tans that Doug Crist and Lynx Shepard shared with me were very similar to the Newfoundland account. Soaking periods are considerably longer than the Eskimo’s overnight, but nowhere near as long as the ‘civilized’ traditions. The Saami do most of their tanning with Reindeer which are generally very thin skinned, and didn’t necessarily oil the skins for softening.
Although bark tanning furs and hair on hides is not a distinct part of the ‘civilized’ tanning traditions, it was done by these native cultures. Both the Chukchee and the Eskimo accounts excerpted above refer to the tanning of furs and hair-on skins (though they also talk about doing hair off skins in a similar way). They both emphasize applying the bark to the flesh side repeatedly rather than soaking the skin. This is also how Lotta Rahme describes the Saami methods of doing hair-on reindeer. Is this to prevent the tannins from discoloring the fur (I don’t know if they would) or simply to keep the stringy bark pulp out of the fur?.
It is hard to visualize the value of lightly bark tanning a hide and softening it without any oils. There would obviously be some affects from the tannin, but what qualities does it give the hide in that relatively short period of time that differs enough from rawhide to bother doing it?
In the overnight examples of the Eskimo and Chukchee, the hides certainly aren’t getting ‘bark tanned’ by any traditional sense of the term. But it does highlight the fact that you can do just about any degree of bark tanning and get some of the effects of tannin. Another example is when you dye brain tanned skins with tannins. Normal dye soaks are anywhere from ten minutes to overnight, and within those short periods of time, the tannin noticeably affects the hides. They contract and get a tighter feeling…more so the longer and stronger the tannin treatment.
Trying to really pin down when something is officially “bark tanned” may have some value, but a more important consideration is at what point has enough tannin bonded to enough proteins to get the effect that you, the tanner, are after.
To me, the main attraction of doing a grain-on soft bark tan is that the grain is simply beautiful and more water repellent than fibrously surfaced leathers. I would also guess, that the more bark tanned a hide is, the better it can be oiled and waxed to make it water-resistant. Tannin is a valuable tool in the tanners tool chest, and knowing exactly how bark tanned or not a hide should be in order to get certain qualities, is part of the ongoing experiments….