Vegetable vs Chromium Tanning; Understanding the difference

[Trouser Bark]

I think there's elements of truth in both viewpoints here. Yes, it does contain Chrome (heck, it's even in the name), but with Chromexcel (CXL) specifically, it's incorrect to lump it into the same as any other chrome tanned leather for any purpose except someone attempting to avoid body contact with leather containing chromium.

Do you think the responses in that interview are objective?

"I mean, the biggest thing is the chrome content. It tends to be lower."

"I think the range is like, 3% to 6%. Something like that(?)"

An objective reference from NIH states the following:

In 90% tanneries worldwide, chromium (Cr) (III) salts are used as tanning agents [8,9]. During the tanning process, Cr compounds cross-link collagen fibers. In this process a significant excess of a tanning agent is applied. The unused Cr compounds remain in wastewater and eventually constitute TS [2]. As a result of tanning, the processed material contains up to 3%–4%(w/w) Cr [1]. Such Cr content is typical not only for the final product (leather), but also for all types of TSTW. The presence of Cr is one of the major problems related to tannery waste treatment—it endangers the environment and human health [3,10]. Cr is considered the second most abundant inorganic ground-water contaminant at hazardous waste sites [11].

Source

If Nick says their chromium salts solution is toward the lower end of the industry's standard 3-6% yet the Nat'l Institute of Health states that leather produced worldwide contains up to 3-4%, there's room for clarity. I'm not vilifying Horween as I like their product but this thread is intended to be objective with few unspecific references. There's a place for a conversation between industry friends but probably not here.

it's probably unfair to characterize it as pseudo veg tan process.

I botched a term prior by referring to a generic Chromium tanning process as CXL. Another member referred to CXL as a "combination tanned" product rather than a re-tan or similar. What is your preferred way to represent the abbreviated veg tan process that follows Horween's Chromium tan process?

 

[Trouser Bark]

While 28 days is a hair shorter than the 30-40 day typical processing time needed for most fully veg tanned leathers, it's probably unfair to characterize it as pseudo veg tan process.

What is your preferred way to represent the abbreviated veg tan process that follows Horween's Chromium tan process?

If there are no objections we'll consider CXL to be a chrome tanned leather with a shortened veg re-tan finish. I don't think it says anything different but it does sound a little nicer. The word pseudo can carry an unnecessary negative connotation. My apologies to anyone that wondered if my reference may have been a slight; it was not.

Let's move on.

 

[Trouser Bark]

We've reviewed the two primary types of tanning processes. There are others but they aren't known for being commercially viable.

The next aspect that I think is interesting is the early US history of tanning. We're talking commercial tanning here as small scale tanning existed wherever people did. If you had a farm you'd have had a few animals and historically it had been common to tan hides for your own use on your own property. But we know that there have been larger scale tanneries for at least 2000 years and since the early US (or pre-US) settlement there have been commercial scale tanneries here as well.

We've all heard of Wall Street and in the 1600's there was an actual security wall for the settlement in that area. At the time the town was called New Amsterdam and it was a dutch settlement. Not far from that same wall and in an area called 'the swamp' near the Brooklyn Bridge was a commercial tannery established 1638. The area was perfect for a tannery of the time as it had access to huge amounts of water and you could easily stock the plant w/ raw hides as ships had access to the shore line from which it was a reasonable hop to the tannery. For the first couple hundred years the (veg) tanning process was reliant upon hemlock bark which didn't grow in the area but was close enough.

After a couple hundred years the general population had become less enchanted with what we'd now think of as a nasty process. Huge amounts of water coming into the plant weren't a big deal but when that same huge volume of water would wash back out of the plant it would have been very nasty. Two hundred years of having polluted the shoreline with animal fat, hair, hide trimmings, wastewater from the tanning process and more would have been far too horrific during a time when society was beginning to develop it's own view of what is or is not an acceptable process near developed areas. Polluting creeks, rivers and shorelines was also beginning to come under public scrutiny. The stench in and around that plant would have been impossible to ignore.

The public still had a strong demand for leather though so much of the industry reverted to smaller tanneries in more rural settings. Little changed aside from the nasty part not being an offensive display, particularly within view of the more delicate among us.

By the mid-1800's large scale commercial tanneries were beginning to disappear and smaller tanneries were rapidly replacing them.

For a little light reading on early colonial tanneries try these links:

https://northernwoodlands.org/articles/article/hemlock-and-hide-the-tanbark-industry-in-old-new-york

https://www.newyorkalmanack.com/2023/07/pergamena-parchments-and-leathers/

If you'd like a peek at what New Amsterdam would have been like, here are the Dutch Colonial Council minutes for New Amsterdam in June of 1638:

https://encyclopedia.nahc-mapping.org/document/dutch-colonial-council-minutes-3-june-1638

A quick google search will provide a lot of other historical detail on the area and people in the 1630's. They were big on written records.

What were these smaller tanneries like? My guess (though I've never seen Stu's) would be that they're something like what Stewart has from Lost Worlds. Oriented away from commodity oriented product and with an eye focussed on something a little more special. The smaller tanner working on his own property has a lower overhead and any extra time it takes to produce a higher end product is his own... so that time is free if he chooses to look at it that way.

There aren't a lot of cows or horses though conveniently hanging around a tannery. Next let's look at one well documented source from the time.

 

[Trouser Bark]

When you were a kid you read books about dinosaurs and sometimes books about men that go away to sea. Whalers, pirates, military types and less so the kind of character we'll call a regular old sailor. Usually working the deck and rigging of a three masted commercial ship they were the early merchant marines.

One of the most well read books that cover early sailors and to some degree the underlying business that supplied the tanning industry was called Two Years Before the Mast and covers the experience of Richard Henry Dana, Jr. while working aboard ship from 1834 to 1836

Dana, Jr., pic taken in 1868

At the time Dana, Jr. sailed as a common seaman from Boston Harbor, around Cape Horn and from there north to California. In several locations the ship stopped to take on cargo, nearly all of which had been unprocessed hides from western US cattle industry. Those same hides were then shipped back around the horn to a tannery facility beyond. If you haven't read the book I'd highly recommend it from a historical perspective.

It's worth pondering for a moment the difference between people now and people then in the context of the leather industry and others.

You have an acceptable stink threshold and beyond that threshold you're inclined to comment on the stench, sometimes irrespective of the source. These hides would have been put into the hold of a wooden ship w/a leaky hull and for the entire trip back the odor would have been harsh by your standards but not even mentioned in the book at all if my memory serves. I would imagine that in the time of the New Amsterdam facility's construction pretty much any odor you were inclined to produce would be perfectly acceptable to those around you. Standards change for not just smells but industrial effluent as well.

Here's an artist's depiction of hides being transferred to the ship off the CA coast in roughly 1835:

Two Years Before the Mast:
https://en.wikipedia.org/wiki/Two_Years_Before_the_Mast

More on Richard Henry Dana, Jr.:
https://www.nps.gov/people/richard-henry-dana-jr.htm

 

[Trouser Bark]

Taking hides in the 1800's from one side of the country to the other is a piece of history on the periphery of the industry and it underscores how important and widespread the industry was not that long ago.

It's also true that during the time of Mr. Dana's experience before the mast the industry was rapidly coming up on a crossroads of sorts.

Mass produced cotton fabrics were cutting into the leather market and society at large was becoming uncomforable with the mess that industry left in its wake. But they hadn't seen the half of it.

It was a time when industry was in transition. What had been largely a veg tan industry for the prior two millennia was rapidly becoming dominated by a new process, a 30x increase in volume and a new kind of effluent. Chromium tanning processes didn't just stink; they were no longer biodegradable. Worse yet, it was strikingly toxic. Our understanding of chemistry was in its infancy and chemical oxidization was a thing but neutralizing a toxin was not.

For the following century industry (and the government) adopted the view that "the secret to pollution is dilution". Thus began a learning process and in roughly the mid 1800's the tanning industry took center stage.

The tanning industry is considered one of the most environmentally unfriendly industrial activities [1].

Source

Next time you walk into your closet and toss on a favorite jacket know that it has a very storied history. Some of it good and some of it less so but all of it worth knowing at least a little about.

I hope some of you have enjoyed looking at an aspect that previously hadn't been tabled here.

 

[Joseph Hill]

Excellent thread. There is a saying (probably in many variations) 'Never go looking how your sausage was made.' I once worked in a factory that built universal gyms, and have spent decades in a comparatively modern auto repair shop. Both contemporary, first world operations, and both have endless stories of how my life has surely been shortened. Even seemingly benign operations like the juice concentrate shop I temped at made you gag. My pop did some controls work at a factory that made maraschino cherries. He swore off manhattens forever. He's also filled more than one radiation card. Everyone should see an operation like the Kennecott copper mine at least once. I went to a Starbucks in San Diego some years ago, and there was a giant prop 65 cancer warning sign in the window. What was the horrible carcinogen in this establishment? Apparently it was the coffee. Limiting the spoiling of our only planet should be everyones goal. But I think you have to unwind society to a pretty primitive level to really make much headway. I had read an article about how leather was tanned before the modern chemistry set, and there were various methods, not least of which being brain tanning, and excrement tanning. As in human excrement. John Chapman was pretty sure there were still some tanneries doing it today.

 

[Trouser Bark]

Excellent thread.

Thank you, Sir! Very much appreciate the compliment and I'm glad you enjoyed it.

I had read an article about how leather was tanned before the modern chemistry set, and there were various methods, not least of which being brain tanning, and excrement tanning. As in human excrement. John Chapman was pretty sure there were still some tanneries doing it today.

If the Romans could soak hides in human urine it would seem anything goes.

Except a deuce though. That does not belong in the soup my jacket was soaking in. Supposedly at one point in history it was tough to find a dog turd in the street as the tanners were all over that stuff. Imagine being the guy that pulled hides out of the veg soaking pit, climbing in up to your knees and more to yank your work out of what wasn't far from being a septic tank. At lunch you climb out of the vat and shine your apple on your tunic, thanking your stars that you didn't have to wear pants or shoes in your line of work.

The industry definitely had some processes to refine. For sure.

Thank you again for the kind words.

 

[3.14nche]

Go for a stroll in the rain wearing a CXL tanned jacket and you're probably going to be fine.

I did it for science a year or so ago.
It will last for a good 30 minutes, then it will start to soak through.
By the first hour you're as wet as with a vegetanned one. By the second you're miserable.

Does anyone have a vegetable tanned jacket that's been in a gully washer? If so please feel free to post a pic of same. I don't have one that's been drenched.

Those have been soaked through multiple times. Not the 2 hours torture as above though.
My experience is that getting caught in the rain, even heavy ones, won't harm a jacket whatsoever.
If it gets wet it dries and that's it.
Leather that could not get in touch with water would be useless to me as it statistically rains every other day here.
Maybe if you're out all day everyday in the rain...
I always think about this post by Jonesy when people are worried about a few drops of water.

Ya mean like this?
View attachment 384114 View attachment 384115 View attachment 384116 View attachment 384117

 

[ABCD]

My experience is that getting caught in the rain, even heavy ones, won't harm a jacket whatsoever.

True, unless the jacket gets absolutely soaked. Tannins might get flushed out in case of full aniline leather, staining the lining of your jacket and whatever your are wearing underneath it. The jacket might need to be reconditioned when dry.

When pigment dyed veg tanned leather gets soaked the topcoat might start peeling off. This happened to one of my Shinki jackets. I've seen it happen to one of those fast aging Fine Creek jackets as well.

 

[raf]

I once saw a RevWar re-enactor get caught in a long-lasting downpour while wearing his normally white cotton coat, which was personally dyed brown. The brown dye leached out of the coat, and dyed all his white clothing, which could be "expensive" depending on whether the dye could be subsequently removed.

Most dye Mfrs advise thoroughly rinsing dyed items, as well as possibly using some specific dye "fixative" chem somewhere along the line.

Not quite the same thing with leather jackets, generally speaking, but I wonder if a sheepskin jacket might possibly bleed dye onto the inner fleece, thus staining the fleece, not to mention other inner clothing?

Also worth wondering if even a simple leather jacket, like an A-2 or a G-1, if improperly dyed, might not also bleed dye.

Granted that most folks have enough sense to not wear sheepskin/fleece in the rain, but things happen. Folks wearing A-2s and G-1s are much more likely to encounter rain.

Perhaps not a major issue with well-made sheepskin/fleece jackets, but perhaps an issue with some jackets (of any type of leather) that are not so well made.

 

[Trouser Bark]

There are many posts on this site referring to older jackets and how older jackets are different beyond an abstract historical provenance. It's true; they are different.

Some aspects are buried in a better understanding of what tanning was like many years ago. Examples...

- An absolutely monstrous volume of water was used in older tanning processes

- A huge array of chemicals were used

- A true combination tanning process was the alchemist's dream up through the 1920's. It was never realized.

- Other quick tan methods had been tried before chromium methods emerged

- Suede is an attempt to salvage an otherwise low quality hide

- Texan cattle (and hides) were instantly recognizable as underfed and of low quality

- Did you know that black jackets were often dyed using a recipe that contained 2 qts of fresh cow blood?

- American horsehides died in service but the best were from Russia and France.

Mr. Allen Rogers wrote an xlnt book in 1922 on early tanning methodology. Sweep tare, grub allowance, and other terms you and I wouldn't have imagined are peppered throughout the book and if there were an aspect that comes to the fore more than the others it's the number of times the hide was handled in the process of preparing it to become your jacket. A link to Google's online version of Dr. Allen Rogers "Practical Tanning" of 1922 is here:

https://books.google.com/books?id=l...=gbs_selected_pages&cad=1#v=onepage&q&f=false

Another book entitled "Practical Tanning" had been written prior by Mr. Louis Flemming. I've seen various initial print dates for it and my thought had been that it was originally written in 1875 but I've recently only seen copyright dates in the early 1900's. A copy of that is here:

https://www.loc.gov/resource/gdcmassbookdig.practicaltanning00flem/?st=gallery


Drawing depicting tannery workers in 1840 Germany:

Another old school tannery:

 

[belfastboy]

It’s been a while since I waved this flag. There was a US Military Specification limiting chromium content in hat sweatbands due to allergic reaction in people like me. (I’m a very sensitive man!) The mil spec is no longer, and so I need to check any new-to-me hats for the chromium myself. It seems to matter most with smaller makers, but not exclusively.

To test for chromium, carefully cut a toothpick.-sized piece of the sweatband from an inconspicuous place on the leather. Burn it over a flame until it’s completely burned to ash. If there is chromium, the ash will have green in it. ANY green means I have the sweatband swapped out.

View attachment 770452 View attachment 770453

I buy my sweats from a US maker that only uses veg tanned roan leather. They are very inexpensive and can't be costing me more than .50 per piece over that of CXL tanned sweats.. Well worth it if saves a client from a forehead rash from the CXL.

 

[belfastboy]

There are many posts on this site referring to older jackets and how older jackets are different beyond an abstract historical provenance. It's true; they are different.

Some aspects are buried in a better understanding of what tanning was like many years ago. Examples...

- An absolutely monstrous volume of water was used in older tanning processes

- A huge array of chemicals were used

- A true combination tanning process was the alchemist's dream up through the 1920's. It was never realized.

- Other quick tan methods had been tried before chromium methods emerged

- Suede is an attempt to salvage an otherwise low quality hide

- Texan cattle (and hides) were instantly recognizable as underfed and of low quality

- Did you know that black jackets were often dyed using a recipe that contained 2 qts of fresh cow blood?

- American horsehides died in service but the best were from Russia and France.

Mr. Allen Rogers wrote an xlnt book in 1922 on early tanning methodology. Sweep tare, grub allowance, and other terms you and I wouldn't have imagined are peppered throughout the book and if there were an aspect that comes to the fore more than the others it's the number of times the hide was handled in the process of preparing it to become your jacket. A link to Google's online version of Dr. Allen Rogers "Practical Tanning" of 1922 is here:

https://books.google.com/books?id=l...=gbs_selected_pages&cad=1#v=onepage&q&f=false

Another book entitled "Practical Tanning" had been written prior by Mr. Louis Flemming. I've seen various initial print dates for it and my thought had been that it was originally written in 1875 but I've recently only seen copyright dates in the early 1900's. A copy of that is here:

https://www.loc.gov/resource/gdcmassbookdig.practicaltanning00flem/?st=gallery


Drawing depicting tannery workers in 1840 Germany:

Another old school tannery:

My Swedish girlfriend's mom used to make blood sausage with 2 quarts of pigs blood in the recipe. I have no issue with a bit in my leather coat.

 

[Trouser Bark]

My Swedish girlfriend's mom used to make blood sausage with 2 quarts of pigs blood in the recipe. I have no issue with a bit in my leather coat.

I'm right there with you. The interesting aspect to me is that blood was then a normal ingredient in a jacket's finish and now it would be a banned biohazard. In '07 I rode a bike from the top of the world to the bottom and in Argentina and Chile it was easy to find blood sausage even if you didn't want it. Not in the US though.