HOW TO TAN HIDES IN THE WINTER
There are a couple of techniques we can use in the winter that we can't use any other time of year. The photo above was taken two years ago this week, in -10C degrees Montana winter. Prior to these thick-skinned Karakul sheepskins being warmed by the fire, they underwent the first winter technique.
(1) Freeze-thawing. This means: to stretch a hide open (usually in a frame but one a fence can work); let it freeze to temperatures below -10C; then let it thaw.
Do this 4 or 5 or 20 times, and the hide will soften on its own.
When water freezes, it swells. This causes the non-structural components of the fibre network to burst. When the ice inside the hide thaws, it then carries some of the ground substance with it as it drains from the hide. These two actions continually make a hide softer and softer with each freeze-thaw.
After a few freeze-thaws, the hide may dry on its own in a dry climate. If this happens, you can rehydrate it and keep going. You want water to be in the hide during this process.
This is the traditional way to soften Beaver and Mustelid pelts, who have thick hides for their size. It works great for Deer, Elk, and Moose. Use this technique with caution on Bison and Sheep. The Sheep above are Karakul - thick-skinned. A regular thin sheepskin may get destroyed by freezing.
(2) UV degradation. This means: leaving a hide in the sun for long enough that UV rays from the sun weaken the fibre structure. Softening thus becomes easier.
Use this technique if you live in a sunny place that doesn't get cold enough for proper freeze-thawing. I recommend leaving a hide outside in the sun for a month, not longer. Too much of a good thing can result in damage to the hide.
Do not use this technique if it is rainy in the winter. Moisture will cause the hide to develop mould and stains, eventually wrecking the hide.
(3) Frost-scraping. This means: dry-scraping a hide when the hide has been frozen, typically as the hide thaws. It's simple to do if it freezes overnight where you live. Just leave the hide in its frame outside overnight, then bring it inside as you scrape. Make sure the hide is close to freezing as you scrape it. This is the magic moment where layers of skin easily pop off from each other. There are three parts to skin that we can dry-scrape:
1. The grain ~ you can skip bucking and wet-scraping, and instead dry-scrape the grain off of a hide. Recommended for Elk, Bison, Cattle; not Deer or smaller.
2. The exterior corium (dermis): this is the junction ebtween the grain and the corium (dermis), where a lot of “hide bits” live. Dry-scraping this exterior corium results in a very soft buckskin with a smooth look.
3. The membrane: this is the ‘inside’ of a hide, where the muscle and fascia were attached. Depending on the age of the animal, a little or a lot of membrane will be present on this side of the hide and it can only be fully scraped away with dry-scraping, not wet-scraping.
So if you live with a long winter + frosty temps, don't be afraid to hide tan! You can actually pursue things those of us in the rainforest only dream about.
I've got this question a lot for Hide Club: FOUNDATIONS as well. And yes! If you join HC:F you 100% can work on your mineral-tanned buckskin and rawhide outdoors. Your mineral-tan buckskin will be made all the easier for it.
The last tip I'd say is: (4) move on inside to soften your hides in the winter. Sitting and softening a hide is one of my favourite things to do in the winter. Make sure you have a solid heat source, get a dehumidifier if you need to (coastal folks), invite friends over to work on their crafts while you soften, or get them to help you :)