The Complete Guide to Raw Denim’s First Wash/Soak: Understanding Starch Removal, Shrinkage Management, and the STF/No-Wash/One-Wash Trinity

1. Introduction — The Challenges This Guide Solves

“I finally got my hands on that pair of raw denim! But how should I wash them for the first time?”

Welcome to the world of Raw Denim. Its unique texture and the personal “fades” that emerge with wear captivate countless denim enthusiasts. However, faced with a brand-new pair of raw jeans, everyone inevitably ponders the “first soak.”

• “Do I have to remove the starch?”
• “What if they shrink too much and become unwearable?”
• “When is the best time to wash them? Should I wash them at all?”
• “What exactly is the difference with STF (Shrink-to-Fit)?”

These questions mark the first steps into the deep world of raw denim, and they are precisely where many beginners stumble.

This guide is dedicated to solving everything related to the “first soak”—a unique, once-in-a-lifetime event that you encounter the moment you acquire raw denim. While the overall lifecycle, including ongoing washing and repairs, is covered in a separate “Complete Guide to Raw Denim Care,” this article focuses specifically on “preparation before washing.”

By reading this, you’ll be able to confidently perform the “first soak” on your raw denim and take a solid step towards cultivating your ideal pair of jeans.

2. Fundamental Knowledge — Clarifying Related Terms and Concepts

To understand the first soak of raw denim, let’s grasp a few basic terms and concepts.

Ounces (Oz.)

This unit measures the weight and thickness of denim fabric. Generally, a higher ounce count indicates a thicker, heavier, and more durable fabric. It influences how “fades” develop and the fabric’s overall appearance.

Weave

Denim fabric is characterized by diagonal lines on its surface, known as twill lines. There are several types of weaves:

• Right-Hand Twill (RHT): The most common type, featuring right-sloping twill lines.
• Left-Hand Twill (LHT): Features left-sloping twill lines. It’s said to be softer than RHT and fades more quickly.
• Broken Twill: Developed by Wrangler in 1964, this weave alternates right and left twill lines. It aims to prevent leg twist.

Dyeing

The indigo dyeing of raw denim typically uses “rope dyeing,” where the surface of the yarn is dyed deeply with indigo, leaving the core white. This allows the indigo to wear away on the surface as the jeans are worn, revealing the white core and creating “fades.”

Sizing (Starch Application)

To prevent yarn breakage and fuzzing during high-speed operation of the warp yarns on the loom, sizing agents are applied to them. This is the primary cause of the stiff feel characteristic of raw denim. For vintage-style selvedge fabrics, corn starch-based agents are common, while modern mass-produced fabrics primarily use PVA (polyvinyl alcohol). The solubility of these agents varies with water temperature. The first soak is also the process of washing away this sizing agent with water, known as “starch removal.”

Shrinkage Allowance

100% cotton woven fabrics are in a stretched state due to tension when they are woven. When first exposed to water and heat, this tension is released, causing shrinkage by the “shrinkage allowance.” The presence or absence of this shrinkage allowance significantly impacts the behavior during the first soak.

Sanforized Process

This is a technique established in 1928 to pre-shrink fabrics. This process generally limits residual shrinkage after wearing to approximately 1% or less. Fabrics marked “Sanforized” are not expected to shrink significantly during the first soak.

Unsanforized (Rigid / Raw / Unsanforized / Shrink-to-Fit (STF))

Fabrics that have not undergone the Sanforized process. Significant shrinkage occurs during the first soak. Levi’s officially states that 501® Original Shrink-to-fit™ jeans shrink approximately 10% in length and 5% in waist.

3. Decision Criteria — Key Axes for Selection and Identification

When choosing raw denim and deciding on the first soak strategy, the following elements serve as important decision criteria:

Era and Model (Brand)

The era and model of jeans vary in fabric characteristics, manufacturing methods, and design details. For example, Levi’s 501 is a prime example, and Cone Mills White Oak fabric (1915–2017) is known for its thick RHT 3x1 selvedge. In contrast, Lee 101 uses LHT 13.5-14 oz selvedge fabric, and Wrangler 13MWZ Cowboy Cut has used broken twill since 1964, showcasing distinct characteristics for each brand.

Details

• Selvedge (Ear): The distinctive edge of the denim, such as the red ear, that is visible along the cut edge. This is a mark of being woven on a shuttle loom.
• Sewing: Details like double stitching and chain stitching also influence the vintage feel.
• Button Fly / Zipper Fly: Older or classic models predominantly feature button flies.

Condition (Sanforized or Not)

This is the most crucial criterion for the first soak. Before purchasing, always check the tag or product description for one of the following:

• Unsanforized / Rigid / Raw / Shrink-to-Fit (STF): No Sanforized process. Significant shrinkage occurs during the first soak.
• Sanforized / Pre-shrunk: Sanforized process applied. Shrinkage during the first soak is limited.
• One-Washed (OW): The manufacturer has pre-soaked the garment once at the factory. Shrinkage has already occurred by the time of purchase.

Products labeled “Shrink-to-Fit” or “STF” are unsanforized and designed to be fitted to the user’s body through a soak.

4. Specific Procedures and Care Flow — Practical Steps

Here, we will explain the standard procedure for the first soak for those following the STF or No-Wash approach. For One-Washed products, as they have already been soaked at the factory, this procedure can be skipped.

Step 1: Preparation

1. Close all buttons and zippers: This prevents loss of shape.
2. Empty all pockets: Don’t forget your smartphone or loose change.
3. Turn inside out: To prevent excessive indigo loss or uneven fading and aim for a more uniform starch removal, always turn the jeans inside out.

Step 2: Water Temperature Selection (Three Schools in Parallel)

Within the raw denim community, there are three differing viewpoints (schools of thought) regarding the water temperature for the first soak.

• (a) Hot Water School (Mainstream for STF)

  • Overview: Use the hottest tap water available (approximately 50°C or higher).
  • Objective: To promote maximum shrinkage and fit the jeans perfectly to your body. Levi’s officially states, “The hotter the water, the more it shrinks,” and this method is recommended if you want Levi’s 501 STF to fit as officially intended.
  • Caution: This will also accelerate indigo loss, leading to more pronounced fading.

• (b) Lukewarm Water School (30–40°C)

  • Overview: Use lukewarm water, slightly warmer than body temperature.
  • Objective: For those who want moderate shrinkage while minimizing initial indigo loss. This is for readers who want to achieve fabric texture while preserving color, such as with vintage-style replicas.

• (c) Cold Soak School

  • Overview: Use room-temperature water.
  • Objective: To minimize both shrinkage and indigo loss.

Step 3: Immersion and Soaking in the Bathtub

1. Submerge slowly: Gently push the jeans into the water, ensuring all air is expelled.
2. Avoid vigorous scrubbing or rubbing: This is to prevent unnatural crease formation and uneven color.
3. STF School Exception: As recommended by Levi’s, one method involves “getting into the bathtub wearing the jeans and letting them dry while on your body, still wet.” This is a technique aimed at maximizing body-fit optimization.
4. Soaking Time: Generally, 30 to 60 minutes is recommended. Secondary sources often suggest that extending beyond 1 hour yields diminishing returns. For those aiming to promote fading, some extend it to around 2 hours.

Step 4: Rinsing

1. Drain the bathtub: Discard the soaking water.
2. Rinse with water of the same temperature: Repeat 2-3 times with water at the temperature selected in Step 2 until the water runs clear.

Step 5: Spin Drying

1. Gently wring out water: Lightly squeeze the jeans by hand to remove excess moisture.
2. Use the washing machine’s delicate spin cycle: Run the machine on the “delicate spin” setting for 30 seconds to 1 minute. Never use a dryer. This can cause excessive additional shrinkage and damage the fabric.

Step 6: Drying

1. Hang dry inside out: As in Step 1, hang the jeans inside out in a well-ventilated, shaded area.
2. Avoid direct sunlight: Direct sunlight can accelerate indigo fading.

Regarding Detergent Use

Whether to use detergent for the first soak is a debated topic within the raw denim community.

• Water-Only School: Chosen to avoid excessive indigo loss from the surface and minimize initial fading.
• Minimal Mild Detergent School: Chosen for more thorough removal of sizing agents and dirt.

In either case, absolutely avoid detergents containing bleach or optical brighteners. These will uniformly decolorize the indigo and ruin the contrast you’ve worked to achieve.

5. Common Mistakes and Pitfalls — Where Beginners Often Stumble and How to Deal With Them

Here are common mistakes made during the first soak and how to address them.

Mistake 1: “After washing, the waist and hem became too short!”

• Cause: Soaking unsanforized denim without considering the shrinkage allowance, treating it as if it were Sanforized.
• Solution:
  • The most critical step is to always check the tag before purchasing to determine if the denim is Sanforized or unsanforized.
  • For unsanforized denim, as explained in the “Shrinkage Allowance” section above, expect approximately 5-10% shrinkage in length and 5% in the waist.
  • For STF models, the intended use is to shrink them maximally in hot water to fit your body perfectly. If you are concerned about over-shrinking, you can opt for lukewarm or cold soaks to reduce shrinkage.

Mistake 2: “The overall color faded too much, and there’s no contrast.”

• Cause: Using strong detergents for the first soak, or excessively rubbing and scrubbing.
• Solution:
  • For the first soak, it is recommended to use only water or a very small amount of mild detergent.
  • Avoid vigorous rubbing and scrubbing; simply let it soak gently.
  • If you wish to minimize fading, choose a cold soak and dry carefully in the shade.

Mistake 3: “After hemming, it shrank and became shorter later.”

• Cause: Hemming unsanforized denim before the first soak.
• Solution:
  • For unsanforized denim, it is essential to perform hemming after the shrinkage allowance has been absorbed during the first soak.
  • Chain stitch hemming also affects the subsequent “puckering” (Puckering refers to the subtle shadows created by fabric shrinkage during washing and drying, particularly at the edges of denim hems and pockets, which give a unique look. It is recommended to entrust this to a reputable tailor.) and it’s advisable to have it done by a trusted professional.

6. Recommended Brands and Models — Examples

Here are some representative brands and models that can serve as a reference when considering the first soak for raw denim. These are based on the information in data/canonical/brand_facts.json.

Levi’s 501

• Characteristics: A quintessential model in the denim world. The 501® Original Shrink-to-fit™ line, in particular, is designed as unsanforized and is intended for users to fit it to their body through the initial soak. The Cone Mills White Oak fabric (up to 2017) is a thick RHT 3x1 selvedge, known for its robust texture.
• First Soak Key Points: The basic approach is to shrink it maximally in hot water to achieve a fit tailored to your body.

Lee 101

• Characteristics: The Lee 101 line uses LHT 13.5-14 oz selvedge fabric. Compared to RHT, it’s softer and tends to fade more quickly. Japanese-produced Lee ARCHIVES lines sometimes feature selvedge fabric from Japanese textile manufacturers.
• First Soak Key Points: Product variations exist (Sanforized, One-Washed, etc.), so checking the tag before purchase is essential. LHT fabric tends to break in more quickly after the first soak.

Wrangler 13MWZ Cowboy Cut

• Characteristics: Since 1964, it has used broken twill, which inhibits leg twist. The currently sold 13MWZ is generally Sanforized 100% cotton broken twill, resulting in minimal shrinkage during the first soak.
• First Soak Key Points: As it’s a Sanforized model, significant shrinkage is not expected. The focus will be on fading and developing wear patterns through continued care.

Note: The above are representative examples. Each brand offers various models with variations in Sanforized, unsanforized, and one-washed finishes. Always confirm the product specifications before purchasing.

7. Conclusion — Checklist for the Reader

The “first wash/soak” of raw denim is the most crucial ritual for cultivating your jeans into a unique pair. We hope this guide will be of assistance in taking that first step without regret.

Ultimately, there is no single “correct” answer among the STF / No-Wash / One-Washed schools of thought. Each prioritizes different values (dimensional accuracy, three-dimensional fading, convenience), and the best choice is the one that suits your preference.

Checklist for a Successful First Soak

• 【Most Important】 Is your purchased denim Sanforized? Unsanforized? One-Washed?
  • Always check the tag. (e.g., “Shrink-to-Fit,” “STF,” “Unsanforized” → Unsanforized / “Sanforized,” “Pre-shrunk” → Sanforized / “One Wash” → One-Washed)
• If you chose unsanforized, when will you wash it?
  • STF School: Immediately after purchase, to fit your body.
  • No-Wash School: After wearing for several months to half a year, to set the creases.
• If washing, what water temperature will you choose?
  • Maximum shrinkage/body fit priority → Hot water
  • Balance of shrinkage and fading → Lukewarm water
  • Minimum shrinkage/fading → Cold soak
• Will you use detergent?
  • For the first soak, water only or a very small amount of mild detergent is recommended. Bleach/optical brightener detergents are strictly prohibited.
• For unsanforized denim, when will you hem it?
  • Always after the shrinkage allowance has been absorbed during the first soak!

Use this checklist as a guide and fully enjoy your raw denim journey.

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Sources and References

• Levi Strauss & Co. — How To Shrink Raw Denim Jeans
• Levi Strauss & Co. — How Do You Shrink-to-Fit
• Heddels — Soaking Raw Denim: The Critical Preliminary Step
• Heddels — How to Soak Your Raw Denim
• Heddels — Raw Denim Care 101
• Blue Owl Workshop — A Beginner’s Guide: Soaking Unsanforized Raw Denim
• Tellason — How and Why To Soak Your Raw Denim
• Wrangler — Cowboy Cut Original Fit Jean 13MWZ
• data/canonical/brand_facts.json (Entries for Levi’s 501, Lee 101, Wrangler 13MWZ Cowboy Cut)
• Existing Article data/published/ja/history/sanforization-process-1928.md
• Existing Article data/published/ja/guide/fade-types-honeycomb-whisker-stack.md
• Existing Article data/published/ja/guide/hemming-chain-stitch-guide.md
• Existing Article data/published/ja/guide/raw-denim-care-guide.md (Phase 1)

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