DU 101: What is Raw Denim?

By Eric Steffen
Founder / Maker
FITTED Underground

Let's start with an admission: "raw denim" is a slightly confusing term. Most denim vocabulary tells you what something is. Raw denim, at its core, tells you what something isn't. It's a negative definition — and understanding that distinction is an important first step towards unlocking this curriculum.

Walk into any mass-market clothing store and the jeans on the rack have been through an industrial obstacle course before they got there. Washed. Stonewashed. Acid washed. Enzyme washed. Sandblasted. Laser distressed. Bleached. Artificially faded. Chemically softened. The manufacturers have done everything possible to make those jeans look and feel like they've already been worn for years, before they've been worn for a single day. Let's be honest here — they're comfortable, but disposable. For denimheads, those fades are manufactured, not earned, and lack the depth and history of a well loved pair.

Raw denim is the opposite of all of that. It is denim that has not been pre-distressed. It's a beautiful sheet of dark blue that's ready to age with you for years to come.

What Raw Denim Is — and Isn't

Denim is a 3x1 weave. What that means is that each horizontal (weft) thread passes under three vertical (warp) threads before it passes over a vertical thread, and then repeats that process all the way across the face of the loom. With classic indigo denim, the vertical / warp threads are indigo and the horizontal / weft threads are white. That results in the fabric having a dark indigo exterior and light white interior. And the 3x1 weave, we should note, results in a diagonal rib, also known as a twill. That's denim. 

Raw denim just means nothing else has happened to the fabric. Or almost nothing else has happened to it. Let me explain.

There are two forms of raw denim. The first is unsanforized denim, also called loom state, shrink-to-fit or, in Japanese, kibata. This fabric goes straight from the loom to the cutting table with nothing done to it whatsoever. No washing, no pre-shrinking, no treatment of any kind. It is as close to the loom as a finished garment can be. The trade-off is significant shrinkage — typically 7 to 10 percent on first soak, which means you need to buy a size or typically two larger to account for what happens when the fabric first meets water. The benefit is that unsanforized denim retains every characteristic from the loom in its most uncompromised form: the texture, the hairiness, the irregularities in the weave. For the devoted raw denim enthusiast, this is often the most prized expression of the fabric.

The second is sanforized raw denim, which is what most raw denim on the market actually is. This is also know as pre-shrunk. After coming off the loom, the fabric goes through a process called sanforization — a mechanical pre-shrinking treatment invented by, and named after, Sanford Lockwood Cluett in 1930. The fabric is moistened with steam, stretched, and heated to stabilize it. The result is that most of the shrinkage happens at the mill before you ever touch the garment, leaving only about 1 to 3 percent to occur after purchase. To be clear, sanforization is a treatment, but it is not pre-distressing. The fabric remains unwashed, unfaded, and untouched in the ways that matter. It is still considered raw denim.

Many people assume raw means completely untreated — that any process applied to the fabric disqualifies it. That's not quite right. The defining characteristic of raw denim is not the absence of every treatment. It is the absence of pre-distressing treatments. Both sanforized and unsanforized denim qualify as raw. The distinction between them is about how shrinkage is being mitigated — not about whether the indigo has been altered.

We go deep on the sanforized vs. unsanforized question — including how to choose between them and what to expect from each — in DU 103: Sanforized vs. Shrink to Fit.

Why Indigo Makes Raw Denim Special

To understand why raw denim behaves the way it does, you need to understand something about indigo — because it's genuinely unlike any other dye in the textile world.

Most dyes penetrate the cotton fiber completely, bonding chemically all the way to the core. When they fade, they fade uniformly and permanently, growing lighter and duller with little character during that process.

Indigo doesn't work that way. It is insoluble in water, which means it can't simply soak into the fiber. Instead it undergoes a chemical reduction process to become temporarily soluble, then bonds to the surface of the yarn when it oxidizes back in contact with air. The core of the cotton yarn stays white. Only the outer layers carry the color.

The process that best produces this result is rope dyeing. Thousands of individual yarn ends are bundled together into thick ropes, then passed through a series of indigo dye vats and lifted back into the air between each dip to oxidize. Six dips, eight, twelve — each one depositing another thin layer of indigo on the surface of the yarn while the core remains largely untouched. The result is what's known as ring-dyed yarn: blue on the outside, white at the heart. It is this structure — surface color over a white core — that makes everything that follows possible.

As you wear a pair of raw denim jeans, the surface indigo gradually wears away. It wears faster where your body bends and flexes, slower where the fabric drapes loosely. Over months and years, the white core begins to show through in patterns that are entirely specific to you — to the shape of your body, your posture, your daily movements. The whiskers at your leg creases. The honeycombs behind your knees. The wallet fade on your back pocket.

A pair of raw denim jeans is a living document. The story written into it is yours — and no one else's. It's one of the reasons denimheads are so passionate about this beautiful fabric.

This is what a pre-washed pair of jeans can never give you. The manufactured fade is, for the most part, frozen in place the moment the jeans leave the factory, applied equally to every pair in production. Raw denim, however, is alive. It fades and changes with you, becoming more interesting the longer you wear it. It's one of those rare products, like wine and leather, that gets better with time. It wears in, not out.

(If you want to understand more about how the fading process works and how to get the most out of it, that's covered in detail in DU 303: How Does Raw Denim Fade? The Science of Fading and DU 304: How to Get Great Fades.)

On Gatekeeping

There is a tendency in the raw denim community — particularly in online forums — toward a culture of expertise as admission price. Threads where beginners get corrected for not knowing the difference between ring-spun and open-end yarn before they've bought their first pair. Spaces where the price of participation seems to be memorizing mill specifications and fade timelines before you're allowed to have an opinion.

This is a problem, and I want to say it directly: you don't need to know any of that to begin your raw denim journey. Education is part of the journey, but not a substitute for experience.

Denim University exists to make this knowledge accessible — to explain clearly and without condescension what raw denim is, how it works, and why it matters. But education is part of the journey, not the prerequisite for starting it. If you're curious about raw denim, that's enough. As Goethe said:

" Whatever you do, or dream you can, begin it. 
Boldness has genius and power and magic in it."

My Story With Raw Denim

I discovered raw denim when I started making jeans — not before.

I grew up wearing jeans the way most people do: as an expression of myself. It felt distinctly American, it connected me to my community, my society and helped define my sense of self. It was, and is, the garment I always reach for first.

As an adult, when I could wear jeans into the office, it felt like a small victory. When I quit my job and started FITTED in 2014, I wanted to make the best quality jeans possible, and that meant using raw denim. What I discovered was something truly special, perhaps similar to your journey. Equal parts rugged and refined and gets better with age? Say less. 

In a sense, raw denim found me. I went down the rabbit hole and there was no looking back.

What Comes Next

Raw and selvedge are two terms you'll often hear used in the same breath — sometimes interchangeably, as if they mean the same thing. They don't. Raw describes how denim is finished — or rather, how it isn't. Selvedge describes how it's woven. Understanding the distinction is one of the most important steps in becoming a genuinely informed denim buyer. That's DU 102.

← Previous: DU 005 — The Brooklyn Denim Revival  |  Next: DU 102 — What is Selvedge Denim? →

Further Reading

• Sanforized vs. Unsanforized Raw Denim — Heddels
• Sanforized vs. Unsanforized vs. Raw — Stridewise
• Sanforized vs. Unsanforized Denim — Tellason
• Raw Denim Guide — Naked & Famous Denim
• Indigo — Denim Hunters
• Rope Dyeing — Denim Hunters

Eric Steffen is the founder of FITTED Underground, a custom jeans and raw denim workshop at 108 Bayard Street in Williamsburg, Brooklyn. He has been making jeans by hand since 2014. Denim University is his attempt to share everything he's learned — about the history, the craft, and the culture behind the world's most enduring garment.