Acid wash process on denim jeansAcid wash process on denim jeans

What is acid wash? Acid wash process on denim jeans?

What is acid wash

Acid wash is the technique used to change the look, feel, comfort ability and fashion of a garment. This is done on garments made from heavy fabrics like denim and jeans. Today fashion is incomplete without denim. Various washing processes are used to change the look of denim or jeans. Among the various washing processes for denim, acid washing is the most popular.

Acid wash on denim jeans has become popular because of its remarkable contrast and attractive color appearance. Acid washing can be done on blue- and sulfur-based fabric clothing. An acid wash is a chemical washing process on denim that strips away the top layer of color and creates a white surface while the color shows through on the layers below the material, giving it a faded appearance.

Acid wash jeans

It is also a type of stone washing, which is done with pumice stone. Due to severe abrasive action, surface fiber damage occurs. Acid was first introduced in the 1980s as an innovative finish on denim garments. This washing is done by soaking the stone in bleach, followed by neutralization.

An acid wash finish treatment creates significant contrast in the color of the denim material. This can be done on indigo and sulfur base fabric garments. Some have tried using a method such as stone washing, yet the discoloration did not occur dramatically or throughout the material.

This was done by soaking the stone in bleach and neutralizing it creating an acid wash effect. But how consistent and smooth the effect this process can have on denim is yet to be found.

Although this process can be done using either mild bleach, chlorine, potassium permanganate etc. The most popular is PP bleach and acid wash will give the best results. The process is very easy to do, but follow all the parameters in the right way to get accurate and repeatable results. Garment load size, machine drum diameter, wet stone/towel and skilled operator.

The acid washing process involved soaking pumice in industrial strength chlorine. However, it was discovered that potassium permanganate is more controllable than and just as powerful as an oxidizer. They simply marinate pumice stone in it and then vacuum pack the stone to the required moisture level. Acid washing was a chemical process on denim that stripped the top layer of color to a white surface with navy blue undertones remaining on the jeans.

Pumice stones are first soaked in a solution of a strong oxidizing agent (either sodium hypochlorite (5-10%) or potassium permanganate (3-6%)) and then applied to the garment by dry tumbling. This results in a locally washed effect with clean blue/white contrast. This technique is called acid washing. It is also called ‘snow washing’ or ‘ice washing’.

The acid washing effect gives sharp contrast to the blue jeans. Acid wash denim does not use actual acid in the washing process. Instead the process uses pumice stones soaked in bleach to change color in a non uniform manner. The result is often a spotted yellowish pattern.

Acid washing is also known as stone washing, which is done with pumice stone. For acid washing, the base color of the garment is removed by spraying acid on specific areas. Washing is performed in two steps: in the first step, the clothes are washed without water and in the second step, with water.

Process Flow Chart of Acid Wash:

Garments loading in machine


Extracting the garments


Soaking of pumice stone

Damp pumice stone

Neutralization the garments


Extracting the garments


Acid Wash Process

The acid wash process involves the use of a few materials and steps to achieve the desired effect on denim jeans.

Acid wash materials required

  • Hydrochloric acid
  • Bleach
  • Water
  • Denim jeans
  • Plastic bucket or tub
  • Rubber gloves
  • Eye protection

The Acid Washing Process: Step-by-Step

  1. Dilute the hydrochloric acid solution according to the manufacturer’s instructions.
  2. Wet the concrete surface thoroughly with water.
  3. Apply the acid solution to the concrete using a sprayer or watering can.
  4. Use a stiff bristle brush to scrub the surface of the concrete, focusing on any areas with stains or discoloration.
  5. Allow the acid solution to sit on the surface for 10-15 minutes, or as recommended by the manufacturer.
  6. Rinse the surface thoroughly with water, using a pressure washer if necessary.
  7. Apply a baking soda solution to neutralize the acid, using a sprayer or watering can.
  8. Rinse the surface again with water, and allow it to dry completely before applying any sealers or coatings.

The Acid Wash Process on Denim Jeans

Creating acid wash denim involves several steps, each contributing to the final look. Here’s a detailed breakdown of the process:

  1. Selection of Denim: The process begins with the selection of the denim fabric. Typically, indigo-dyed denim is chosen as it reacts well to the bleaching process.
  2. Pre-washing: The denim is pre-washed to remove any impurities or sizing agents that might interfere with the bleaching process. This step ensures the fabric is ready to take on the acid wash effect uniformly.
  3. Preparation of Pumice Stones: Pumice stones are soaked in a solution of chlorine bleach. These stones are the key to creating the uneven, marbled effect on the denim. The stones are usually large and rough, capable of abrading the fabric.
  4. Washing with Pumice Stones: The pre-washed denim is then tumbled with the bleach-soaked pumice stones in a rotating drum. As the stones rub against the fabric, they create random, lighter patches by removing some of the indigo dye.
  5. Neutralization: After achieving the desired effect, it is crucial to neutralize the bleaching agent to stop the bleaching process and prevent further damage to the fabric. This is typically done with an anti-chlorine agent or a simple rinse in water mixed with a neutralizing chemical.
  6. Final Washing and Softening: The jeans are given a final wash to remove any remaining chemicals and pumice particles. Often, a softening agent is used to make the denim feel more comfortable and wearable.
  7. Drying and Finishing: The denim is then dried and undergoes any additional finishing processes, such as distressing, to enhance the vintage look. This could include adding rips, tears, or additional fading.

Detailed Process with Chemical Composition and Measurements

1. Selection of DenimChoose high-quality, indigo-dyed denim suitable for acid washing.DenimNot applicable
2. Pre-washingPre-wash the denim to remove impurities and sizing agents.Water, detergentWater: as needed, Detergent: 2-3% w/w (weight of fabric)
3. Preparation of Pumice StonesSoak pumice stones in a chlorine bleach solution to prepare them for washing.Chlorine bleach (NaOCl), Pumice stonesBleach: 5-10% w/w (weight of stones), Pumice: 1-2 kg per pair of jeans
4. Washing with Pumice StonesTumble the pre-washed denim with bleach-soaked pumice stones in a rotating drum.Pre-soaked pumice stonesDuration: 15-30 minutes, Temperature: room temperature
5. NeutralizationNeutralize the remaining bleach to stop the bleaching process.Sodium thiosulfate (Na2S2O3) or sodium metabisulfite (Na2S2O5)Neutralizer: 0.5-1% w/w (weight of fabric), Water: as needed
6. Final Washing and SofteningRemove any remaining chemicals and pumice particles, and soften the fabric if needed.Water, softening agentWater: as needed, Softening agent: 1-2% w/w (weight of fabric)
7. Drying and FinishingDry the denim and apply any additional finishing processes, like distressing.Air or mechanical dryer, distressing toolsTemperature: 60-80°C (if using a mechanical dryer)

The Appeal of Acid Wash Jeans

Acid wash jeans stand out for their unique, retro aesthetic. Each pair is slightly different due to the randomness of the bleaching process, making them a popular choice for those seeking a one-of-a-kind look. The marbled, high-contrast appearance adds a bold statement to any outfit, embodying a blend of nostalgia and contemporary fashion.

Caring for Acid Wash Denim

Due to the bleaching process, acid wash jeans can be more delicate than untreated denim. Here are some care tips:

  • Wash Sparingly: Wash your jeans only when necessary to preserve the fabric and color.
  • Use Cold Water: Wash in cold water to prevent further fading.
  • Avoid Harsh Detergents: Use mild detergents to maintain the integrity of the denim.
  • Air Dry: Whenever possible, air dry your jeans to prevent shrinkage and maintain their shape.

Effects of Acid Wash on denim jeans

The acid wash process has several effects on denim jeans:

Fading and Distressing

The acid solution and bleach work together to remove the top layer of indigo dye on the denim jeans, resulting in a faded and distressed appearance. The degree of fading and distressing can vary depending on the amount of acid used in the wash.

Softening of the Fabric

The acid and bleach solution also breaks down the fibers in the denim, making the fabric softer and more comfortable to wear.


Due to the harsh chemical treatment involved in acid wash, denim jeans may experience some shrinkage during the washing process. It is important to consider this when choosing the size of your acid washed jeans.

Advantages and Disadvantages of Acid Wash on Denim Jeans


  1. Unique Aesthetic Appeal:
    • Vintage Look: Acid wash jeans offer a distinctive, marbled appearance that stands out from regular denim. The random fading patterns create a vintage, worn-in look that is highly fashionable.
    • Individuality: Each pair of acid wash jeans is unique due to the inherent randomness of the bleaching process. This individuality appeals to consumers looking for one-of-a-kind clothing items.
  2. Versatility in Fashion:
    • Adaptability: Acid wash jeans can be styled in various ways, making them suitable for casual, streetwear, and even semi-formal occasions.
    • Trend Resurgence: The revival of 1980s and 1990s fashion trends has brought acid wash denim back into popularity, appealing to both nostalgic customers and new generations.
  3. Softened Fabric:
    • Comfort: The acid wash process often results in a softer fabric compared to untreated denim. The repeated washing and neutralizing steps help in breaking down the fibers, making the jeans more comfortable to wear.
  4. Perceived Value:
    • Premium Pricing: Due to the complex process and the unique outcome of each pair, acid wash jeans are often seen as premium products, allowing brands to charge higher prices.


  1. Fabric Durability:
    • Weakened Fibers: The bleaching process can weaken the denim fibers, making the jeans more prone to wear and tear over time. This can reduce the overall lifespan of the garment.
    • Potential Damage: Excessive bleaching or improper neutralization can cause permanent damage to the fabric, resulting in holes or excessive fading.
  2. Environmental Concerns:
    • Chemical Use: The use of chlorine bleach and other chemicals in the acid wash process can have negative environmental impacts if not managed properly. These chemicals can contribute to water pollution and pose health risks to workers if proper safety measures are not in place.
    • Water Consumption: The process requires significant amounts of water for washing, neutralizing, and rinsing the denim, contributing to water wastage.
  3. Production Complexity:
    • Labor-Intensive: The process is labor-intensive and requires skilled workers to achieve the desired effect. This can increase production costs and limit scalability.
    • Quality Control: Maintaining consistent quality and effect across different batches of denim can be challenging due to the variability inherent in the process.
  4. Care and Maintenance:
    • Special Care: Acid wash jeans may require special care to maintain their appearance and integrity. Consumers need to follow specific washing instructions to avoid further damage and preserve the unique look of the jeans.
    • Color Fading: Over time, the color of acid wash jeans can fade further, potentially altering the intended look and appeal of the garment.


Acid wash denim jeans offer a unique and fashionable aesthetic that appeals to many consumers. However, the process has both advantages and disadvantages. While the distinctive look and soft texture are appealing, the potential drawbacks in terms of fabric durability, environmental impact, production complexity, and care requirements need to be considered. By weighing these pros and cons, manufacturers and consumers can make informed decisions about incorporating acid wash denim into their products and wardrobes.

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