The Horween Leather Company has been tanning leather in Chicago for a long, long time—120 years, as of next year.
For the duration of that history, it’s remained in the hands of five successive generations of Horweens. With Skip Horween currently currently at the helm, the tannery produces all of the leather used in NFL footballs and NBA basketballs, in addition to a truly incredible quantity and variety of boot leather put to use by everyone from Allen Edmonds and Alden to Onderhound and Østmo. It would probably be faster to list the bootmakers that don’t use Horween than the ones that do.
Horween also specializes in a few processes that—if you look at the tanning industry as a whole—are fairly uncommon, including combination tanning (where hides receive both chrome based and vegetable based tanning agents) and hot stuffing (which inundates the hide with heated fats and waxes to make it softer, richer, and easier to care for).
If you want to see those processes in the flesh (decent pun??), we still have limited tickets for an exclusive guided Horween tannery tour at our Boot Camp mega-expo this November in Chicago.
With that in mind we sat down with Nick Horween, the tannery’s Vice President, and Phil Kalas, who works with Horween leather every day at Ashland Leather Company (both also host the fantastic Full Grain Podcast!), to find out everything you need to know about Horween’s leathers, starting with the most famous of them all…
Many of the photos here were taken from the exceptional Patina Project app—which also powers our Stitchdown Patina Thunderdome boot-aging contest with over $45,000 in prizes. Thunderdome FIVE tarts Oct 1 2025, more details here!
Shell Cordovan
Tannage: Vegetable tanned
Finish: Hot stuffed, glazed
What to Know: Shiny, stiff, expensive, and largely indestrucible; tends to “roll” instead of creasing at flex points
Horween has been tanning shell cordovan since before you were born (unless you were born in 1904), and shell’s very much the original Horween product—for its first few years the tannery didn’t make anything else. It’s dense, resistant to abrasion, and not very stretchy, all of which made it the leather of choice for… razor strops. Eventually the modern safety razor would make straight razors (and their strops) a rarity, but before that happened 20th century shoe-powerhouse Florsheim, also headquartered in Chicago, found that those very same properties made for excellent and hardy dress shoes, and a very good thing was born.
Shell cordovan is an equine (horse) leather, technically a “subcutaneous membrane”—a fibre structure beneath the skin—that’s 8 to 10 times denser than a more typical bovine hide. That density makes it slow and difficult to tan: cordovan spends almost two months in “the pits” soaking up the vegetable tannins that turn the unpreserved hides into durable leather. The “shells” are only around 1.5-2 square feet, and occur at random depths within the hide, varying in size, thickness, and density. All of those factors come together to make shell cordovan very expensive—not just to tan, but also to work with.
Density also varies within individual shells, making them difficult to cut and skive—tools catch if they suddenly hit a dense spot, or skip if they hit a loose one. On shoes, the fact that cordovan dosen’t like to stretch makes it particularly difficult to last the uppers.
So why do so many people find it worth the trouble? Shell takes on an incredible sheen both new and with a bit of care work, and has a depth of color you’d be hard pressed to find anywhere else. It’s also resistant to cuts and abrasion (sometimes for decades) and durably beautiful: no other leather burnishes and patinas quite like it. In “regular” leather there’s a layer of grain on one face, with layers of looser fibers beneath it. When repeatedly flexed, the grain delaminates from the fibers below. Delamination produces “break”, the wrinkling and creasing you find on leather shoes where the vamp flexes. With no grain, cordovan doesn’t break, instead forming smooth rolls. Aesthetically this is pretty subjective—people tend to love it or less-love it—but we fall solidly into the love camp.
On footwear, shell cordovan is shiny and easy to maintain; it lasts basically forever and keeps getting better the whole time. It also tends to be fairly stiff. Lighter colors can be prone to water spotting, and though it wont crease it will, as mentioned, form rolls, sometimes quite strong ones. Of course, the limited supply of responsibly sourced hides and the lengthy tanning process means shell cordovan’s biggest downside is its price. We’ve already written an even deeper guide to how shell is made and how it ages, which you can check out here.
Workshoe Butt
Tannage: Vegetable tanned or combination tanned
Finish: Hot stuffed, sometimes polished
What to Know: Dense and hardy, burnishes well
Shell cordovan is a membrane beneath the surface of the skin, but the layers above it don’t just get shy and run off; you have to shave them away, and if you don’t, you’ve got Workshoe Butt: full thickness horsebutts with the shell still inside.
Workshoe Butt, like cordovan, is a cut of hide and not a tannage, so in theory you could make Waxed Flesh Workshoe Butts, Chromepak Workshoe Butts, or anything else you dream up. Horween generally uses a modified version of the Chromexcel tannage. The hides spend their first month alongside shell cordovan in the tanning pits, and then get pulled out before being retanned and finished like Chromexcel (more on that below), except chromium salts are added to the retan in order to make the leather stronger and more heat resistant. That’s the opposite of most combination tanned leathers, which get chrome salts first and vegetable tannins during the retan.
The final product is generally somewhere between six and eight square feet, with about half of that area containing of two shells beneath the surface. Historically the idea has been that if you’re clicking a boot it won’t all include shell, but the person at the clicking table can be strategic about placing it where it counts—usually the vamp—for some extra durability. Workshoe Butt is dense and hardy, and it takes burnishing really well, even on the non-shell sections. Phil says he’s clicked some shell-less wallets with it and you’d be hard pressed to tell; it’s a leather that seems determined to get smooth and compact as it wears.
There are two versions: a regular version which is polished to even out the grain and remove cosmetic imperfections, producing a smoother, shiner, pull-up leather; and a crust version that’s more matte, more natural, and more likely to have scars and markings. The best comparison here is probably sanding wood.—the grain isn’t gone, you’re just seeing a different cross section of it.
The magic of this stuff is undersold by its initial appearance—that’s not to say it looks bad new, but it’s nothing compared to what it looks like after a few months (or years) of hard wear.
Chromexcel (and Its Many Variants)
Tannage: Combination tanned
Finish: Hot stuffed, slightly corrected grain
What to Know: Soft, flexible, practically self-conditioning
As we’ve already seen, Chromexcel can refer to a number of leathers, but they all have a couple of things in common. Chromexcel is a tannage, and specifically combination tannage, meaning that the leather is first tanned in drums using chromium salts and then retanned using vegetable tannins. Chrome lends high tensile strength and heat resistance, while veg adds burnishability, better patina potential, and subjectively, a better feel. The leathers in the Chromexcel family are hot stuffed with different blends of fats and receive a variety of finishes, but the unofficial line where the apple has fallen too far from the tree is when you modify with the specific blend of tanning and retanning compounds—change that blend and you no longer have Chromexcel.
We’re going to speedrun the family tree to give you an overview of some of the most notable variants.
Classic/Marine Field Shoe: This is almost always what people are talking about when they talk about Chromexcel, and Horween sells it as simply “Chromexcel”. No prefix, no modifier. It’s a flexible and malleable steer hide hot stuffed with a ton of waxes and oils which is soft but durable and tends to produce comfortable footwear. In grain-out Chromexcel, a little buffing is all it takes to remove lighter scuffs and scratches. One of the most ubiquitous leathers in the industry, it sits right at the balance point between “work” and “dress” leathers. Generally you’ll find it on rugged-leaning boots designed more for everyday wear than the job site, though Nicks and White’s make very capable work boots out of the stuff. Natural Chromexcel in particular can develop some pretty striking patina. Roughout Chromexcel specifically finished for the reverse side is often referred to as “Marine Field Shoe”.
Wooly: Wooly Chromexcel uses extra lanolin during the hot stuffing process. Lanolin, otherwise known as wool fat, is a grease that’s found naturally in wool and removed during preparation for spinning and weaving. The effect is a leather that’s shinier, almost to the point of being self-polishing, and also darker in color than other variants. It’s also unbuffed. (Nick Horween: “It’s not like the lanolin you’re used to seeing… we buy the lanolin that’s stuck to the bottom of the drum when they’re done cooking it. The stuff that looks like tar is the stuff that’s good for leather.)
Natural M’s: Natural M’s is a variant of a variant. It’s a version of mechanical chromexcel, an extremely strong and dense tannage Horween used to produce for use in gaskets on engines and other machinery. Like workshoe butts, it’s first chrome-tanned, and then sent to the pits. Natural M’s is often run on bison to accentuate the already intense grain. It’s tougher than classic Chromexcel and not quite as soft or stretchy.
Beaufort: Chromexcel is usually hot stuffed with enough oils and waxes that it’s almost impossible to glue, making it difficult to use on cemented shoes and other glued products. Beaufort’s stuffing blend isn’t as rich, making it possible (though not easy) to glue. If you see Chromexcel used on cemented sneaker or dress shoe, it may be Beaufort.
Buccaneer/Navigator: These two leathers technically cross the line above in that the they have a modified retanning blend that differs from classic Chromexcel. But we’re including them because they’re essentially (in Nick’s words) waterproof Chromexcel. Of course “waterproof” leather can mean a lot of different things, but you can basically trust that if you’re wearing well-made shoes in Buccaneer you’ll be able to splash through some water with dry feet and intact boots. Scuba dive at your own risk.
Waxed Flesh
Tannage: Combination tanned
Finish: Hot stuffed; ironed, dyed, and waxed on the flesh side
What to Know: Stiff hand; nap will stand up over time, but can be re-waxed
Here’s where the lines get even blurrier: waxed flesh is certainly a Chromexcel variant. It’s tanned and finished almost exactly the same way as classic Chromexcel, except all of the finishing that’s normally done to the grain is done to the flesh side of the leather (including the wax finish, hence waxed flesh). That said, Waxed Flesh is common enough and different enough on boots that we wanted to break it out on its own.
Visually the cool thing about waxed flesh is that as it wears, the nap —which has been ironed smooth, dyed, and waxed—begins to stand up, creating two-toned effect, changing the texture, and showing off the wear. Applying a coat of wax lays it back down again should you ever want to.
Functionally this makes the leather extremely hard wearing, because wear that would cut or scratch a grain leather just pushes the nap around, and you can effectively wax away most minor damage. One side effect of finishing the flesh is that Waxed Flesh is quite stiff, especially at first.
When leather bends—especially thick leather—the side of the hide “inside” the turn is compressed and the side “outside” the turn is stretched. Imagine a marching band going around a corner: the people on the inside of the curve travel a much shorter distance that the people on the outside of the curve, so the people on the inside have to slow down and bunch together, and the people on the outside have to speed up and spread out, or everybody looses their spacing and crashes into each other.
On grain-side boots, the looser nap fibers can pull apart and stretch out, but finishing them locks them together, preventing this from happening. Waxed Flesh is often used unlined, because the grain of the leather is on the inside of the boot anyways. Because of this, it’s often used in heavier weights.
Some finished-flesh leathers start to expose their nap very quickly with wear—Horween’s waxed flesh tends to take a bit of work, and be just a bit tougher to break in. One of the unique things about it is just how much control you have over the patina process. In medium and dark colors periodic rewaxing can keep the uppers somewhat close to new (you’re never going to be able to replicate at home what tannery equipment can do), give or take some darkening and shine on high wear areas. If you want high contrast and fuzzy, just leave them alone. As with other roughouts or suedes, you also don’t need to worry about grain break.
Cavalier
Tannage: Combination tanned
Finish: Lightly hot stuffed, slightly corrected grain, bright dye colors
What to Know: Shiny and stiff
Cavalier is also in the Chromexcel-verse, but it uses its own retanning blend and gets a different mix of oils. It’s designed to be really good at one thing: taking bright colors. Classic Chromexcel comes in pretty much any color that’s brown, from brown to very light brown (natural) and even red-brown (Color 8). We’re pretty sure under a spectrometer black Chromexcel would show up as an extremely dark brown. But the retanning and hot-stuffing process puts too many tannins and fats into the leather for bright colors to render clearly.
Cavalier uses a lighter “blond” retannage and gets less grease, allowing it to take bright colors like the evocatively named ‘London Bus Red”. If you’re seeing it on a piece of footwear, it’s almost always because the maker wanted didn’t want to be restricted to earth tones.
Predator
Tannage: Combination tanned
Finish: Heavily waxed
What to Know: Very durable; burnishes to a shine with hard use.
With only fifteen years under its belt, Predator is a “new” tannage in the world of Horween, and it’s sort of Horween’s take on what’s sometimes called a “crazy horse” leather. The bottom line though: this stuff burnishes like crazy.
It’s a really rich and waxy finish with a lot of highs and lows in terms of color, and it also has a more matte finish than classic Chromexcel. Both of these traits make Predator a more rugged looking leather. The retannage uses more modern synthetic resins in addition to mimosa bark to produce a more consistent and stronger leather than a more traditional combination tannage, backing up the tough look, but if you put a pair of Predator boots on the burnishing wheel you can allegedly get a very shiny, almost dressy look—that certainly maps onto what we’ve seen, which is some really striking shine and darkening on dome pairs (mostly Nicks Boots) in Predator.
What’s happening is that on a micro scale, the peaks and valleys in the surface of the leather are getting filled in by wax to form a new, smooth surface, which means that all of the light that lands on the boots gets reflected back at the same angle instead of being scattered by the valleys and peaks. It’s the same process that happens if you polish your shoes, but the amount and type of surface wax in Predator speeds up the process and allows it to happen naturally without much help.
Predator tends to show up on work boots and rugged everyday boots, and it’s probably best to think of it as a performance oriented tannage that’s also designed with an eye to look and patina. If you need cool boots to really beat up it’s a pretty strong choice.
Chromepak
Tannage: Chrome tanned
Finish: Heavily hot stuffed
What to Know: Can develop less patina than other leathers; fairly water resistant
Chromepak is the first straight-chrome tannage we’ve talked about so far, meaning there are no vegetable tannins involved in the process at all: chrome base tannage, chrome retannage. The stuffing blend is heavier on both oils and waxes, and it’s pasted—literally glued to a pane of glass—so it doesn’t shrink as it dries, meaning there’s a lot less stretch. It’s soft, water resistant, and extremely strong. It won’t patina quite like a veg or combination tanned leather does (though it will still age and express wear plenty well), but it’s more water resistant and can take more abuse that most other leathers.
What this comes down to can be summed up pretty succinctly: “You can do a lot of bad things to it and it doesn’t really care”. You might also be drawn to the matte finish or the consistent way it ages if you’re lukewarm on intense patina.
Chamois and Snuffed Suede
Tannage: Combination tanned
Finish: Sanded, oiled if chamois
What to Know: Fine surface nap; less creasing due to the sanded finish.
Horween carries out a lot of different processes and tans a lot of different leathers, far more than most tanning operations. But one thing it doesn’t do is true suede, meaning a “split” leather that doesn’t include the grain. The closest it gets is Snuffed Suede, a nubuck style corrected leather where the surface is sanded down enough to create some nap, but the grain isn’t completely gone.
It’s chrome tanned, veg-retanned, and fat liquored with a blend of oils and waxes that lend themselves to burnishing, and which are also light enough that Horween can produce snuffed suede in a range of colors from bone to jet black, including bright lavenders, yellows, and baby blues. Snuffed Suede doesn’t have the same nap or “fuzziness” as the suedes you’re used to—it has a very fine, velvety texture and from a distance might be mistaken for a matte grain leather. It’s also worth mentioning that we’re not talking about “snuff suede” either, which is the snuff color of C.F. Stead’s Janus Calf Suede.
Chamois (technically pronounced SHAM-ee, although we can be rightly be accused of calling it SHAM-wah over the years) is Snuffed Suede that’s been treated with an oil finish on both sides. As a result of the dark oils, the color range goes from expansive to fairly narrow, but it more than makes up for it in texture and finish. With use and burnishing it can take on a look similar to waxed flesh, with the nap laid down and darkened to a shine.
It was popularized (at least recently) by Alden, as was reverse Chamois. As Nick heard it, the story goes like this: an Alden retailer ordered a sample in Chamois, and whoever happened to be on the production line at the time clicked it backwards and assembled the upper with the flesh side out. They were about ready to get fired, but when they asked someone to take a look at the shoes they looked good enough that Alden started running reverse chamois, now more common than the smooth version.
Essex and Dublin
Tannage: Vegetable tanned
Finish: Hot stuffed, ironed, oiled (Essex) or waxed (Dublin)
What to Know: Supple compared to other veg-tans; can crease more wildly than other Horween leathers
Essex and Dublin are, on the footwear front, Horween’s veg-tanned bovine leathers of note. Essex uses a slightly tweaked version of the tannage developed for shell, with a similar blend of fat liquors, or at least the current version does. The original was a little more intense.
Here’s how Phil tells the story:
“I came in to work one day. Skip Horween had his mad scientist hat on—he was all wide eyed—and said “you have to come look at this”. He had the wild idea to take a steerhide and put it alongside cordovan in the pits. And it was awesome, like, five times the mass of a normal hide…” Too heavy and dense, as it turned out, for just about any application.
That “original Essex” was tweaked until it became usable, and the current version of the tannage has changed a lot. In fact, it’s notable for being more supple and less stiff than many of the full veg-leathers that are out there. It’s ironed during the finishing process, resulting in a final product with a lot of shine. If that final product gets a oil finish, it’s Essex, and if it gets a wax finish, it’s Dublin.
The waxed finish gives Dublin some extra density and means you can remove scuffs and scratches by heating up the wax and melting it back into place. Essex and Dublin produce patina ranging from a soft glow crosshatched with mild creasing to a pretty serious transformation more typical of lighter shades. Its creases and hairline folds are more dramatic than the grain break on most leathers. It’s part of the look, but definitely something to keep in mind, whether you’re chasing it or trying to steer clear.
Going Deeper
If you want to get a better feel for any of the leathers listed here, it’s worth taking a look at Patina Project app, which documents the way hundreds of different leathers wear and age, and also gives you a better sense of just how much one leather can vary when made into different boots or subject to different lifestyles.
At the end of the day all of the leathers we’re talking about here are really very excellent for footwear; they’ll handle the wear most people put them through without issue. The joy is in the tactile details—the feel, the look, and yeah, the smell—because Horween goes to pretty extreme lengths to make leathers that aren’t just mechanically sufficient, but also quite pleasant to experience.
As we found out talking Nick and Phil, a whole lot of questions at Horween are answered with “they tried it a century ago and we do it the way that turned out better”. The best way to experience the result is to pick one and wear it really hard.