Explaining Sanforized, Unsanforized, and One-Washed Denim

Raw Selvedge denim is a uniquely beautiful thing - a starchy, slow-woven twill dipped in vats of living colour. It’s crunchy and unyielding to the hand at first, but soon rewards a wearer’s patience with a custom fit and the utmost comfort. But the biggest challenge associated with raw selvedge denim lies not in its break-in but in its sizing.

Raw, “unsanforized” denim is a tricky and unpredictable fabric for the simple fact that it’s guaranteed to shrink after its first few washes. It takes forethought, planning and a small leap of faith. To even the most seasoned of denim enthusiasts, shrink-to-fit denim is a real roll of the dice.

Which is why we made the decision to one-wash all of our unsanforized jeans from here on out. This helps us retain the natural qualities of raw, unsanforized denim whilst also removing the guess work of sizing.

But if that leaves you confused as to what the differences are between unsanforized, sanforized, and one-washed denim then you’re not alone. Read on for a little guide to the key differences.

What’s the difference between sanforized, unsanforized, and one-washed denim?

Simply put, Sanforized refers to pre-shrunk, ready-to-wear denim. Unsanforized refers to loomstate, shrink-to-fit denim. One-washed refers to unsanforized denim that has been soaked in water to remove initial shrinkage. Sanforization is essentially a set of processes used to treat raw denim before it’s cut into jeans. Lengths of selvedge fabric are typically fed through a machine, where they are heat treated, steamed, and pressed. This removes the shrinkage and makes for a more stable denim. The pressing of the fabric typically results in a smoother, more uniform denim.

Unsanforized denim, on the other hand, skips this heating process entirely. The untreated or “loomstate” selvedge denim is left as is, and will therefore shrink upon its first wash. Sometimes, unsanforized denim will shrink up to two or three tag sizes. The lack of steaming, singeing, and pressing also means that the denim retains its full, fresh-off-the-loom character. The uniqueness imparted by the cotton yarns, the texture derived from the weave, and the irregular shades of indigo achieved in the dyeing are retained in all their glory.

One-washed denim refers to jeans that have been cut, sewn, and assembled from either sanforized or unsanforized selvedge denim before being carefully rinsed. This is either done by the brand themselves or else in-house here at our Rivet & Hide stores. Some of our brands - like Iron Heart and Momotaro - offer their denim sanforized and one-washed. This makes for a stable and comfortable denim that’s very easy to size. 

This isn’t to be confused with washed or stonewashed denim, which are processes designed to artificially age or distress denim. One-washing respects and retains the qualities of raw denim but simply removes that initial shrinkage.

What are the benefits of one-washed selvedge denim?

When we one-wash unsanforized denim we get the best of both worlds: a rich loomstate fabric with a tonne of natural character and practically no shrinkage. One-washing denim comes with a bunch of other benefits, too. Namely:

Easy sizing. Getting the shrinkage out of the way before the jeans even hit the rails makes for simple sizing. You no longer have to guesstimate what your size will be post-soak. What you see on our size guides is exactly what you’ll get. Your new jeans will be ready to roll from the moment they leave our rails and hit your legs.

Easy Hemming. Likewise, any hemming required to customise the inseam of your new pair of jeans can be done before we ship to you. No more waiting for that first soak before you hem your jeans. Hit this link to find out more about our Union Special Hemming Service.

Added comfort. Both sanforized and unsanforized denim comes with some initial stiffness and starchiness. One-washing your jeans helps to loosen things up for a softer hand and a quicker, more gentle break-in. 

Added character. One-washing removes any out-the-door sheen or uniformity in the denim and kickstarts its natural evolution. Whether that amounts to some added range and depth in a denim’s indigo tones or an intensifying of a yarn's “slubby” texture depends entirely on the fabric. 

Added roping. In the case of unsanforized denim, the shrinkage brought on by one-washing causes the fabric to pucker slightly around the seams. This causes the much-coveted “roping” effect seen around the hems and pockets of a well-worn pair of jeans.

Longer-lasting denim. Not a product of the one-wash per se, but washing your jeans on at least a semi-regular basis can help prevent “blowouts” and extend the life of your denim. For more info on looking after your denim, check out our handy guide.

In summary:

  • Sanforized denim is pre-washed and will not shrink after a wash.
  • Unsanforized denim is NOT pre-washed and WILL shrink after a wash.
  • One-washed denim is unsanforized or sanforized denim that has been pre-washed to remove shrinkage and soften things up.

What unsanforized & one-washed jeans do you carry?

We’re so glad you asked. We stock a number of Japanese selvedge denim brands that offer unsanforized denim - Pure Blue Japan, Samurai, Studio D’Artisan to name a few. They all make beautiful, unsanforized jeans with some of the most impressive and coveted fabrics that the jean-making craft has to offer.


Shop our full range of selvedge denim jeans here.