What happens when leather is tanned?  This question came up because an
acquaintance bought a leather coat and says it smells too strong to wear. 
It does not smell different that other leathers, just much stronger.  Does
anyone know what could account for this extremely strong smell and how to deal
with it?

14 responses total.

The tanning of leather is done to precipitate/coagulate the proteins of
the skin, and to remove the outer, hair-bearing, layer. The former is,
properly speaking, "tanning". After the outer layer is removed (with
lime), the skin can be tanned with a variety of chemicals. Most common are
tannin (hence the name), metallic salts (chromic acid in particular), or
with turkey red oil (prepared from castor oil and sulfuric acid). Chamois
leather is tanned by the last, oil, process. Some of the varieties of
tanning could leave a strong odor - or an odorant could be added so that
the leather smells like "leather" (in someone's opinion). Your friend
could wash the coat, but better look up how to do that, so as to not "dry"
(remove the oils) and make it hard. 

This response has been erased.

        Acid Tanned, Vegetable tanned & Chrome Tanned.

        The former normally implies a 3rd world country and Urine-Tanning;
        (stinking as only piss can)

        The latter implies the chromates & furniture-gloss leather. They
        are usable as linings, too.

        In between we have the carvable/stampable materials such as Tandy
        sells to us.

        I work in leather, so don't bother wasting my time in
        contradictions, please.

Unassailable, huh? 

Wow, urine-tanned...I think I'd prefer skin with the fur still on it
to that!

   there's brain-tanning, too, but that method isn't used too much anymore.

Then their is the best way to tan, which in my humble, non-professional
opinion is brain tanning. The brain of each animal is suffient to tan the hide
and you get such a soft, soft leather, sutible for clothing and other
stuff. I've watched the process and enjoyed the results.

Disgustingness sounds like it's beneficial.  I wonder if anyone has
tried a fecal/vomit mixture...should make leather smoother than silk!

No, silly, it means that less of the animal is wasted. Brain tanning is
natural and good use of what has given it's life. You americans are so
squemish...geez.

How does it work? Is anything else added? All tanning consists of
precipitating the proteins in skins with one agent or another. A brain is
protein, and would not be effective by itself.

Well, lets see....we took the hide, mixed hard wood ash and water and covered
the hair side with it then buried it for three days. Then the hair came out
just like that (snap). Then we took the brain, mixed in some liver and smeared
the stuff over the hide (inside side) then stretched and allowed to dry. Then
we worked the hide over a board till soft. Don't recall if anything else was
done or not.

Sounds like the lye from the ash did the tanning and the brain supplied the
oil/fat.

The lye does the de-hairing (removes the epidermis, in fact). There is
certainly a lot of fatty material in brain, so that should soften the
skin, but I would venture to say that it wasn't *tanned*, and is more
subject to rot than leather tanned by the acid/chrome/oil methods. 

What about the enzymes in the liver - any chance they contribute to tanning?

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