Do you have any idea what it means when a pair of boots is labeled “vegetable-tanned” or “oil-tanned”?
I’ll be honest: when I first started boot-shopping years ago, I had no clue. But thankfully, I’ve learned a lot in the years since, and it’s helped me choose better-quality, longer-lasting, and more gorgeous boots.
So here’s everything you need to know about the most common leather tanning methods, including the pros and cons of each and which is ultimately the “best” for your boots.
The Most Common Leather Tanning Methods
Chrome tanning, vegetable tanning, and oil tanning are the most common leather tanning methods. But each method has its own unique properties and yields different results.
Fun Fact: The name “tanning” derives from the tannins (or tannic acid) added into the drums or vats where hides are soaked. The tannins help to displace the water naturally found between the protein fibers, and, in so doing, lock together those fibers.
Regardless of tanning type, the tanning process ultimately results in a water-resistant or even waterproof material. Using various types of tannins for the process will affect the resilience, look, and feel of the finished product.
What is Chrome Tanning?
Chrome tanning is a process that uses chromium sulfate (aka chromium salt) to soak the leather.
The leather is left to soak in vats filled with saline baths, and the salt actually accumulates between the protein fibers to produce a waterproof layer.
Chrome tanning is one of the most common modern tanning processes because of how widely available chromium sulfate (or sulfite) is. The fact that the tanning can be completed in a matter of days makes it highly popular among the manufacturers mass-producing leather goods.
It also has a very long shelf life. The chemical coating of the leather will repel water rather than absorb it, making it much more resilient to moisture damage than vegetable-tanned leather.
However, be aware that the chromium salt used can be very harsh on the environment. It’s not biodegradable, and the tanning process uses a significant amount of chemicals, energy, and water.
What is Vegetable Tanning?
Vegetable tanning is the oldest tanning process in the world and has been used by leatherworkers for thousands of years.
This process uses tannic, oil-rich extracts from the roots, seeds, bark, and husks of various plants and trees to soak the hides.
From start to finish, the tanning process typically takes anywhere from two weeks to two months, but the end product is well worth the wait.
Vegetable-tanned leather tends to be pricier due to the longer tanning time and the materials’ cost. However, the slower tanning process leads to a more beautiful material with a highly visible grain and softer hand-feel.
What is Oil Tanning?
Oil tanning is a method that is a more uncommon method in modern leather manufacturing than chrome or vegetable tanning.
Various animal-derived oils (such as fish oil) are used for the oil tanning process.
Rather than letting the oils sit in a vat with the soaking leather, oil tanning requires pounding the oil into the dried hides (a more time-consuming, and thus more expensive, process).
The oil is infused into the leather until it entirely replaces the moisture between the protein fibers, creating an impermeable water-resistant barrier.
Oil tanning is used most commonly for chamois leather (derived from goat or sheepskin), but there are a few manufacturers (such as Timberland, Thursday Boot Company, and Irish Setter) that use oil tanning to produce their boots.
Oil-tanned leather products tend to be softer and require less break-in time. They’re also lower maintenance than vegetable or chrome-tanned leather products.
Which is The Best Leather Tanning Method?
I want to clarify one thing: the term “best” is highly subjective.
It’s impossible to declare “vegetable tanning is the best method” or “chrome tanning is superior” because each tanning type I’ve explained in this article has its strengths and weaknesses.
Let’s talk a little bit about what makes each good, as well as their drawbacks.
Quick and Inexpensive
Chrome tanning is highly popular in modern leathermaking because it’s the cheapest and quickest tanning method.
The hides only need to remain submerged in the vat for a day (or sometimes even less), then they can be removed and processed. This shorter treatment time allows for mass production of leather goods at a far lower expense to the manufacturer.
Many “budget” leather boots are made using the chrome tanning process because of how much quicker and cheaper it is.
Good Water Resistance
The water-resistance provided by chrome tanning is very reliable, and the treated leather is highly durable.
This is great for things like work boots, where being resistant to moisture and tough enough to stand up to harsher conditions is paramount.
Terrible for the Environment
However, as I mentioned above, chrome tanning is terrible for the environment.
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With chrome tanning, massive vats are filled with industrial chemicals (like chromium sulfate or sulfites) that can raise pollution levels when absorbed into the atmosphere.
The chromium salts and other chemicals used have also been scientifically proven to be carcinogenic, with tannery workers who work in chrome-tanning plants suffering higher rates of various cancers!
Unsuitable for Tooling and Doesn’t Age Well
Chrome-tanned leather doesn’t age very well, either. It tends to lose its luster within a far shorter period than oil or vegetable-tanned leather, and may begin to show signs of wear and tear faster. It’s also more prone to cracking with frequent use and exposure to the elements.
Finally, chrome-tanned leather is unsuitable for tooling because the tanning process stretches and thins it out.
While it’s definitely more budget-friendly, tanners use it chiefly for products built to last for only a few years.
Tough and Resilient
Vegetable-tanned leather is tougher and more resilient, and the waterproofing provided by the tanning process is far less likely to leak than chrome-tanned leather.
No one can question the durability of vegetable-tanned leather, either. Well-made veg-tanned leather products can easily last for ten to twenty years with the proper care and maintenance.
Vegetable tanned leather also patinates beautifully, developing a unique look the longer you wear it. It tends to darken and develop a richer hue as it oxidizes, giving the leather a warm and lived-in appearance.
A ‘Safer’ Tanning Process
Finally, the vegetable tanning process is far greener than chrome tanning, and is safe for the leatherworkers in the tanneries and factories. Since vegetable tanning primarily uses tannins derived from plant sources, such as tree bark, the process involves fewer harsh chemicals, making it more environmentally friendly.
The Process is Slower and Pricier
Vegetable tanning is a slower, more involved tanning process, which means less material can be produced. The end-product of vegetable tanning tends to be pricier because there is simply less of it available.
However, being patient definitely pays off in the long run.
Produces Soft Leather with a Shorter Break-in Time
Oil-tanned leather is very soft, requires far less break-in time than either vegetable or chrome-tanned leather, and needs less maintenance and upkeep. The oils used in the tanning process help keep the leather pliable, making it comfortable to wear and less prone to stiffness over time.
Attractive and Distinctive Finish
The glossiness of oil-tanned leather often enhances the saturation of colors. The shiny surface reflects light, making the colors appear more vibrant and deep.
Oil-tanned leather also has a tendency to develop a distressed and worn-in appearance over time. This characteristic is often appreciated for its vintage and lived-in look, giving products made from oil-tanned leather a unique charm.
Labor Intensive Process
Oil tanning is far less commonly used for boots, chiefly because the process is far more labor-intensive than simply soaking the leather in vats filled with chromium salt or vegetable tannins.
In fact, it’s so uncommon that a lot of the leather marketed as “oil-tanned” is actually tanned using either chrome or vegetable tanning, then bathed in oil (or wax) to infuse it with that lipid-based waterproof membrane.
A Glossy Finish But Hard to Polish
The look of oil-tanned leather is also highly distinctive, with a glossy finish that won’t appeal to all boot wearers. While the glossiness of oil-tanned leather often enhances the saturation of colors, The shiny surface is better suited to formal footwear.
Despite being somewhat shiny, it’s oddly tough to polish oil-tanned boots because the oil in the material stops the leather from soaking up the polish.
Here’s a quick recap of everything so you have an easy-to-read breakdown of all the pros and cons of each leather type:
|Chrome Tanned Leather
|– Cheapest tanning method
– Quick tanning time
– Great for mass production of leather goods
|– Harsh on the environment
– Hazardous to factory workers
– Lacks durability; will crack and/or show signs of age
– Can’t be tooled
|Vegetable Tanned Leather
|– More durable than chrome-tanned leather
– Develops a more gorgeous patina
– Can be tooled
– More environmentally friendly
– Uses natural ingredients
– Better waterproofing and overall resilience
|– Longer treatment time required
– More expensive
|Oil Tanned Leather
|– Highly water-resilient finish
– Glossy good looks
– Soft right out of the box
– Minimal break-in time required
– Minimal maintenance required
|– May be too glossy for all purposes and styles
– Not a common manufacturing process
– May be labeled “oil tanned” but is actually “vegetable-tanned or chrome-tanned and finished in oil”
What About Synthetic Tanning?
Synthetic tanning is a tanning method we don’t endorse because it uses petrochemical-based acrylic resins.
Acrylic resins are cheaper than vegetable-based tannins and so widely available (thanks to the prevalence of petrochemicals) that they can be produced on a massive scale. This makes synthetic-tanned leather products significantly cheaper.
Synthetic tanning produces less environmental damage than chrome tanning, and the water resilience provided by the resins is superior to oil and vegetable tanning.
However, synthetic-tanned leather is nowhere near as tough or beautiful as vegetable-tanned leather. It’s typically used for purses and wallets, not boots.
As I stated at the beginning of this article, each of the tanning methods has its pros and cons, so it’s impossible to quantitatively state which is the “best.”
However, having done the research and lots of hands-on testing, I’ve drawn my own conclusions about which material is the smarter investment.
I love a pair of budget-friendly but well-built leather boots, so chrome-tanned leather certainly appeals to my cheapskate side.
But after wearing oil-tanned boots (like my Red Wing Iron Rangers) and vegetable-tanned boots (like the Thursday Captains), it’s become clear that the pricier tanning methods ultimately result in a better-looking and more durable product.
What is the best tanning method for leather?
Vegetable tanning produces a longer-lasting, more reliable, and better-looking material than chrome and synthetic tanning. While it takes longer for the material to be treated—anywhere from two weeks to two months—the finished product is superior to chrome-tanned leather.
Which tanning method is considered the most sustainable?
Vegetable tanning is more sustainable by far. The tannins used are derived from tree bark and other plant sources. With vegetable tanning, no industrial chemicals are released into the environment, and leather workers aren’t exposed to carcinogenic and skin-damaging toxins.
Which process is the fastest for tanning leather?
Chrome tanning leather is exponentially faster than vegetable and oil tanning. The entire tanning process can take under 24 hours and won’t typically last more than 48 hours at the extreme.