Cotton kills. But the reason why it’s the absolute worst material for outdoor clothing is also what enables it to be one of the best. Here’s why it could replace Gore-Tex in your gear closet.

The Trouble with Cotton

Long story short, cotton fibers are hollow and the particles they’re made of carry a negative charge. Water molecules are positively charged, so they fill up those hollow fibers, then hang around. That’s why cotton can absorb up to 27 times its weight in water, and why it takes forever to dry out. And because water conducts heat away from the body 25 times faster than air, having all that water stuck inside your clothing can lead to hypothermia, even in relatively mild weather.

That stinks, because as we all know from our casual wear, cotton is incredibly comfortable when it’s dry and can be produced in a wide range of weights and styles. The T-shirt you’re wearing right now is light and soft. Your jeans are heavy and strong.

Oil and Water Don’t Mix

Hundreds of years ago, sailors noticed that wet sails caught the wind more efficiently than dry ones. Filling the fibers of the sail fabric with water stopped the wind from blowing through. But wet sails were also extremely heavy, and it could be impossible to keep them damp in dry weather. So, they started rubbing fish oil, grease, and stuff like that into them. That created a fabric capable of stopping the wind, but that remained relatively light and would hold this windproof treatment for a long time.

That same windproof, fairly light, long-lasting sail fabric also shed water. Which turned it into pretty good clothing for the high seas: those same 15th-century sailors used sail scraps to make outerwear.

Because fish oil smells like, well, fish oil, linseed oil became the go-to for oilcloth clothing. But it wasn’t perfect either, as it would grow stiff and crack in the cold, melt out of the clothes on hot days, and discolor with age, from clear to yellow. (That’s why old timey paintings of fishermen all have them wearing yellow garb.)

Then, in 1830, a German chemist discovered that he could make a wax from the byproduct of turning petroleum into lubrication oil. That byproduct wax was odorless, colorless, and its melting point could be changed with additives. Paraffin has since been used to coat wheels of cheese, seal food containers, and make chewing gum, candles, crayons, and even solid rocket fuel. Among its many uses, it could also impregnate fabric. Most importantly, it was incredibly cheap.

All of a sudden, clothing companies had an ideal substance with which to coat canvas that was more stable than linseed oil. Waxed cotton was born.

Both Waterproof and Breathable

It’s just as important for outerwear to let water vapor—sweat—escape as it is to keep rain out. That’s why we don’t all wear rubber suits when the weather's bad. Fortunately for us, water droplets are relatively large compared to the particles in water vapor, so microscopic holes can be used to let the latter pass through, while making rain bounce off.

That’s the founding principle of waterproof-breathable membranes, the first of which—Gore-Tex—was invented in 1969. It employed a stretched fluoropolymer with nine billion pores per square-inch to make rainwear you could work up a sweat in, comfortably.

As described above, waxed cotton ended up achieving a similar function almost by accident. By rubbing oil into sail cloth, those 15th century sailors were impregnating the fibers with a wind and waterproof material. Woven tightly, those now-waterproof fibers were close enough together to block rain drops, while the microscopic gaps between them allowed sweat vapor to escape.

“The wax doesn’t coat the fibers, it fills them,” explains Judy Martin. Her family-owned company, Martin Dyeing and Finishing, has been the premier supplier of American-made waxed cotton fabrics since 1930. "That's why we don't wax burlap." The cotton fabric being waxed needs to have a tight enough weave that the now-waterproof fibers will actually block the rain.

The reason waxed cotton works so well is that its hollow fibers, which are otherwise so problematic for their propensity to soak up water, are able to be filled up with, and hold onto, wax, rendering the fibers themselves water tight. Martin applies the wax to fabric woven tightly enough that the proximity of the now-waterproof fibers stops rain droplets on the surface.

Wax in the Real World

Pick up a waxed-cotton garment in a store, and the first thing you’re going to notice is that it’s heavier and stiffer than you expect. By filling the cotton fibers, wax also makes them less flexible and adds weight. Fabric weights are measured in ounces per square yard. Martin tells us that a 14.6-ounce canvas, when waxed, will weigh 19.84 ounces. (Heavy, but far less than the multiplier of 27 you have to use when calculating how much water weight a cotton garment can take on.)

Stiffness is hard to quantify, but heavier waxed cotton garments are famous for their ability to just about stand up on their own, when new. A lot like leather, waxed cotton is a material that improves with age and wear. A jacket that’s stiff on a store shelf, will soften up and conform to your body if you spend a few nights sleeping in it. That's the quickest way to break in either material, by the way.

Again like leather, waxed cotton will develop a patina and a fit all your own over months of wear. It’s capable of lasting decades with regular use.

Look at a beat-up old waxed cotton jacket, and you’ll notice distinctive “cracks” running across it. “When you fold waxed cotton, and it changes color, you’re seeing the cotton fibers without wax,” says Martin. She explains that her company typically dyes fabrics half as dark as desired before waxing them, then the wax itself adds the extra shade. The only exception is black fabric, which receives black, rather than gray, dye, and on which you won’t notice as much lightening in the folds.

Over time, with exposure to the hot sun and driving rain, the impregnated wax will eventually begin to run out of the cotton fibers, requiring re-application. So, again like leather, waxed cotton requires some maintenance. Fortunately, wax is an easy substance to work with. Just acquire a tin of whichever wax was originally used, heat it up in a pot of hot water, then rub it in to the fabric. A hair dryer or heat gun can help any excess fully melt and distribute through the fabric.

You can also apply clothing wax—Martin’s Martexin is a good option—to originally untreated items of cotton clothing. Just be thorough in your application if you want to achieve a significant degree of weather protection, and make sure you test out your results before you have to rely on them. Like anything you can both make and buy, factory-produced results tend to be more consistent than home-brew alternatives, especially on your first try.

Old Versus New

How does waxed cotton compare to high-tech, waterproof-breathable membranes? In some ways it works better, and in some ways it’s worse. In the end, there’s probably room for both in your life.

Waxed cotton’s main advantages are looks and durability. Most items of clothing made from the material harken back to a time—the late 1800s and early 1900s—when it was in common use, and are fashionably retro as a result. And it remains popular in the world of fancy British field sports, like wing shooting. If you enjoy dressing like a toff, you probably already own some. The heavy canvas that’s typically used is also strong and resistant to both punctures and abrasion. That makes it pretty good at fending off sharp tree branches, or even light motorcycle crashes. Unlike your fancy textile jacket, it’s also impervious to flying embers from a campfire. Your fancy name-brand hardshell has a useful life of maybe five years, if you’re using it often. I’ve had one of my waxed cotton coats for 20 years, and it’s still young by that material’s standards.

Where waxed cotton will never compete with a technical hard shell is weight and freedom of movement. Garments made from waxed cotton are measured in pounds, whereas modern technical pieces are typically just a handful of ounces. The latest waterproof-breathable membranes now feature four-way stretch; waxed cotton barely bends, let alone moves with you.

What about the all-important ability to keep rain out, while also breathing as well as possible? Until recently, I’d have called it a toss up. Waxed cotton does without the wet-out-prone face fabric that was typical of hardshells for decades, but recent innovations—better DWR finishes and membrane-on-the-outside technologies as are used in the Columbia OutDry jacket—have improved hardshell weather resistance immensely. The latest ultra-breathable membranes—Polartec NeoShell, Gore-Tex ShakeDry, Derzimax NX—are also ridiculously breathable. But a decent waxed cotton piece is at least as comfortable to wear as an inexpensive hardshell, like the Marmot Precip, even if it will be a few pounds heavier.

Of course, all the above merits of waxed cotton require maintenance. You need to reapply wax annually, though you should probably be washing the oils out of your technical hardshells, and reapplying their DWRs, at around the same frequency. Pick up a neglected waxed coat and it’ll let you down just as bad as a technical jacket with all its pores blocked by grease and smoke.

Due to their retro nature, many waxed cotton pieces are also handicapped by un-waxed cotton liners that sort of ruin the whole point of the material by trapping sweat next to your body and blocking the breathability. But you can cut the tartan out of a Barbour if you don’t mind the feel of wax next to skin. Just like with modern technical clothing, a proper layering approach works best here. Merino longjohns, and an insulating mid-layer, work just as well under waxed cotton as they do under anything Arc'Teryx makes. Just here you won’t look like a renegade from a ski hill during a night out on the town.