How is Leather Made?

The global leather goods market was valued at USD 498.57 billion in 2024. It is expected to grow from USD 531.07 billion in 2025 to USD 855.36 billion by 2032.

This growth is driven by increasing consumer demand for durable, high-quality leather products, as well as the expanding use of leather across various industries.

Beyond consumer goods, leather is integral to several industrial applications. The automotive sector, for instance, relies heavily on genuine leather for vehicle interiors.

Similarly, the furniture industry utilizes leather for upholstery, contributing to its sustained demand.

But how is leather made?

The process of making leather involves several key steps: curing, soaking, liming, tanning, retanning, dyeing, and finishing. 

Traditional tanning methods, such as vegetable and chrome tanning, have been used for centuries, while modern innovations continue to evolve the industry.

Understanding the intricacies of leather production is essential for consumers, manufacturers, and environmental advocates alike.

In this post, we will explore everything you need to know about leather production steps, environmental impact, and innovations in production methods.

What is Leather?

Leather is a durable and flexible material created by tanning animal hides, primarily from cattle.

The tanning process chemically stabilizes the collagen fibers in the skin, preventing decay and enhancing durability.

Leather has been utilized for millennia in various applications, including clothing, footwear, furniture, tools, and accessories, due to its strength, versatility, and aesthetic appeal.

The key characteristics of leather are:

1. Durability: Properly tanned leather is resistant to wear and can last for decades.
2. Flexibility and Malleability: Leather can be easily shaped and molded, making it suitable for a wide range of products.
3. Breathability: It allows air and moisture to pass through, providing comfort in clothing and footwear.
4. Water Absorption and Desorption: Leather can absorb moisture and release it over time, helping to regulate humidity.
5. Thermal Insulation: The air pockets within leather provide insulation, keeping the wearer warm and comfortable.
6. Aesthetic Appeal: Leather offers a unique texture and appearance, which can develop a patina over time, enhancing its visual appeal.

Historical Background and Evolution of Leather

The use of leather dates back to prehistoric times. Early humans utilized animal hides for clothing, shelter, and tools.

In ancient civilizations such as those of Egypt, Mesopotamia, and the Indus Valley, leather was utilized for various purposes, including footwear, armor, and containers. The tanning process during this time involved natural substances, such as tannin-rich tree bark.

During the Middle Ages, leatherworking became a specialized craft in Europe.

Guilds were established, and leather was used extensively for bookbinding, clothing, and armor. Techniques have improved, leading to higher-quality and more diverse leather products.

The Industrial Revolution brought significant advancements to the leather production industry.

Mechanization enabled mass production, and new tanning methods, such as chrome tanning, were developed, thereby reducing processing time and costs.

Today, leather remains a popular material, valued for its durability and aesthetic qualities.

However, environmental concerns have led to the development of alternative materials, such as plant-based leathers made from cork, apple, or cactus.

How is Leather Made?

The leather manufacturing process involves steps to transform raw animal hides into durable, versatile materials used in a wide range of products.

Here are the leather production steps:

Step 1 – Curing

Immediately after an animal is skinned, its hide is susceptible to bacterial decay. To prevent decomposition, curing is employed as a preservation method.

The most common leather curing methods include:

• Salting: Applying salt to the hide draws out moisture, inhibiting bacterial growth.
• Freezing: Lowering the hide’s temperature slows down bacterial activity.
• Chilling: Maintaining the hide at low temperatures delays decomposition.

These methods ensure that hides remain intact during storage and transportation to tanneries.

Step 2 – Soaking

Upon arrival at the tannery, cured hides are often dehydrated and contaminated with dirt and salts. Soaking reintroduces moisture, restoring the hide’s pliability.

This process also removes residual curing agents and surface impurities, preparing the hide for subsequent treatments.

Step 3 – Liming

Liming involves immersing hides in an alkaline solution, typically containing lime (calcium hydroxide) and sodium sulfide. This step serves multiple purposes:

• Hair Removal: The alkaline solution breaks down hair follicles, facilitating hair removal.
• Fat and Protein Removal: Unwanted proteins and natural fats are eliminated, cleaning the hide.
• Fiber Swelling: The hide’s collagen fibers swell, opening up the structure to better absorb tanning agents later.

Step 4 – Tanning

Leather tanning can be achieved through different methods, such as:

1. Vegetable Tanning: Use of Tannins from Plant Sources

Vegetable tanning utilizes natural tannins extracted from plant materials like tree bark.

This method is time-consuming, often taking several weeks, but results in leather that is firm, durable, and develops a rich patina over time.

2. Chrome Tanning: Use of Chromium Salts

Chrome tanning employs chromium salts, significantly reducing processing time to just a few days. The resulting leather is softer, more flexible, and resistant to water and heat.

This method is prevalent in modern leather production due to its efficiency and the desirable qualities of the finished leather.

Step 5 – Retanning

Retanning involves subjecting the tanned leather to additional tanning agents to refine its characteristics.

This step can enhance attributes such as color uniformity, softness, and durability, tailoring the leather to specific end-use requirements.

Step 6 – Dyeing

Dyeing imparts color to the leather, either for aesthetic purposes or to meet specific design requirements. Common dyeing methods include:

• Drum Dyeing: Hides are tumbled in large drums with dye solutions, ensuring deep and uniform color penetration.
• Spray Dyeing: Dye is sprayed onto the leather’s surface, allowing for precise color application and effects.

Step 7 – Finishing

Finishing enhances the leather’s appearance and performance. Leather finishing techniques may include:

• Polishing: Buffing the surface to achieve the desired sheen.
• Embossing: Impressing patterns or textures onto the leather surface.
• Protective Coatings: Applying finishes that protect against moisture, stains, and wear, while also influencing the leather’s gloss and color.

Each of these steps is integral to producing high-quality leather, with variations in techniques and materials allowing for a diverse range of leather products suited to different applications.

Types of Leather

Leather comes in various types, each with distinct characteristics and applications.

Here are the four main types of leather:

1. Full-Grain Leather

Full-grain leather is the highest quality leather available. It is made from the top layer of the hide and retains the natural grain, including imperfections like scars and wrinkles.

This type of leather is known for its strength, durability, and ability to develop a unique patina over time, enhancing its appearance with age.

Common uses of full-grain leather include high-end furniture, footwear, bags, and accessories.

2. Top-Grain Leather

Top-grain leather also originates from the top layer of the hide but undergoes sanding or buffing to remove imperfections.

This process results in a more uniform appearance and makes the leather thinner and more pliable than full-grain.

While it doesn’t develop a patina as fully as top-grain leather does, top-grain leather remains durable. It is often used in products where a consistent look is desired, such as in certain types of furniture and accessories.

3. Genuine Leather

Typically, genuine leather refers to lower-quality leather made from the layers of the hide that remain after the top-grain has been removed.

It often undergoes extensive processing to achieve a uniform appearance but lacks the durability and longevity of higher-grade leathers.

4. Bonded Leather

Bonded leather is a material composed of shredded leather fibers combined with polyurethane or latex binders, which are then pressed onto a fiber or paper backing. It typically contains only 10–20% actual leather.

While it offers a leather-like appearance at a lower cost, bonded leather is less durable and prone to peeling over time. It’s commonly used in budget-friendly furniture, bookbindings, and fashion accessories.

Environmental Impact of Leather Production

Water Usage and Wastewater in Leather Manufacturing

Processing 1 m² of bovine leather can require up to ~370 L of water.

Small artisanal tanneries still use significant water; for example, a case study in Ghana reported 1.17–2.12 m³ of water per day used in a single small tannery.

Approximately 52% of the total effluent volume originates from the early leather beamhouse operations and tanning process (soaking, liming, etc.), with the remaining 48% from post-tanning/finishing.

Another study shows that in Bangladesh’s leather industry, the water footprint (including farming and processing) was estimated at ~34,000 m³ per ton of bovine leather, with wet processing stages (soaking, liming, tanning, etc.) accounting for ~97% of the footprint.

These figures highlight the extensive water demands of conventional tanning operations.

That said, the tannery wastewater is among the most polluted industrial effluents, characterized by extreme levels of organic matter, solids, and toxic substances.

Globally, literature indicates that processing 1 ton of raw hide can produce wastewater containing on the order of 240 kg COD, 100 kg BOD, 150 kg suspended solids, 170 kg salt, 80 kg sulfate, 10 kg sulfide, and 5 kg chromium (as chromate).

Such high pollutant loads give tannery effluent a dark color, strong odor, and high pH, making it difficult to biodegrade.

If discharged untreated, this wastewater can devastate local ecosystems.

The high organic load depletes oxygen in receiving waters, harming aquatic life. Toxic substances like sulfides (from unhairing) can kill fish, and chromium and other heavy metals can accumulate in soil and biota.

These findings highlight the environmental impact of leather production; however, there is more to it, including chemical treatments and sustainable practices.

Chemical Treatments: Toxins, Health Effects, and Regulation

Tanning and finishing processes rely on many chemicals (chromium salts, lime, sulfides, dyes, solvents, preservatives), which have significant environmental and human health impacts.

About 80–90% of the world’s leather is tanned with chromium(III) sulfate (“chrome tanning”).

Chrome tanning is popular because it stabilizes collagen efficiently, but it introduces toxic heavy metal pollution.

Studies estimate that only ~20% of applied Cr(III) binds to the leather, leaving the rest to enter wastewater and solid waste.

As a result, tannery effluent often contains elevated Cr(III) (dozens of mg/L), and sludge from chrome tanning is considered hazardous waste due to its high chromium content. 

Moreover, recent work on leather products found that brightly colored chrome-tanned leathers can release Cr(VI) in small amounts, posing dermal exposure risks to consumers.

Consequently, for humans, tannery workers chronically exposed to Cr(III) exhibit higher incidences of DNA damage, genotoxic effects, and oxidative stress in their cells.

For example, a study from South Asian tanneries confirmed that Cr(III) exposure is associated with chromosomal breaks and oxidative DNA base modifications in workers. It may contribute to respiratory issues and skin ulcers.

Besides chromium, sulfide compounds used for dehairing can release toxic hydrogen sulfide gas and contribute to oxygen-depleting sulfide in effluent, endangering both workers (risk of asphyxiation in poorly ventilated areas) and aquatic life.

Additionally, preservatives used on hides (e.g., bactericides and insecticides applied during storage) can introduce persistent organic pollutants.

According to a research paper, certain leather dyes have been shown to harm aquatic organisms; for example, earlier research observed that common leather dyes like Bismarck Brown can reduce red blood cell counts in fish (toxicological effects on marine life).

Managing these chemical hazards is a major regulatory concern worldwide.

In developed regions (EU, US), strict regulations (e.g., the EU’s REACH and Integrated Pollution Prevention & Control standards) limit allowable effluent contaminants and mandate treatment.

The EU’s Best Available Techniques (BAT) Reference for tanneries sets guideline emission levels and practices for chrome, sulfide, nitrogen, etc.

Many tanneries have installed effluent treatment plants and chrome recovery units to comply, which has significantly reduced their pollution output.

However, in many low- and middle-income countries, enforcement of environmental regulations is inconsistent.

Given this, while global initiatives (such as UNIDO guidelines and Leather Working Group audits) are pushing the industry toward safer chemical use, the sector still faces the challenge of balancing economic viability with the cost of compliance in many regions.

Sustainable Practices and Technologies in Leather Manufacturing

Here are the key sustainable practices and technologies:

1. Chrome-Free or Reduced-Chrome Tanning

Vegetable tanning (using plant polyphenols) is a traditional chrome-free method; it eliminates chromium but can require larger amounts of tannins and produces its own organic load.

These alternatives can greatly reduce metal pollution; however, each comes with trade-offs in leather properties or other environmental aspects (some require high chemical input or yield higher COD in effluent).

A study explains that while many “metal-free” tanning solutions exist, none fully replicates all the performance advantages of chromium, so active research continues to optimize these methods.

2. Water Recycling and Cleaner Production

Many new projects focus on reducing water usage and reusing wastewater in the tannery industry.

In-plant measures, such as reusing soaking and liming liquors, utilizing short floats (minimizing water in drums), and implementing advanced filtration systems, are being implemented.

One research paper highlights that “reuse and recycling of tannery wastewater are important for sustainable development”, especially in water-scarce regions.

Additionally, enzyme-assisted unhairing (using proteolytic enzymes in place of some sulfide and lime) has been shown to produce lower sulfide content in wastewater and less solid waste (hair), while maintaining leather quality. 

3. Enhanced Effluent Treatment Technologies

Traditional treatment methods (lime precipitation for chromium, biological treatment for organics) sometimes fall short of completely removing all toxins.

Emerging techniques such as adsorption using novel adsorbents (e.g., utilizing tannery solid waste itself converted into activated carbon to capture dyes and metals), membrane bioreactors, and constructed wetlands tailored for tannery effluents.

While these technologies can be expensive, they point the way toward closed-loop systems where water and chemicals are continually recovered and recycled.

4. Waste Valorization (“Zero Waste” Initiatives)

Leather processing leaves behind substantial solid wastes, trimmings, splits, shavings, and sludge, which historically go to landfills.

Recent research is exploring “waste-to-value” strategies, repurposing these by-products instead of disposing of them.

For example, a research paper demonstrates that anaerobic digestion of fleshings can produce biogas (methane) for energy, process leather shaving dust into adsorbent material for water treatment, convert collagen-rich wastes into gelatin or collagen peptides for industrial use, and even explore the use of hydrolyzed leather proteins in animal feed.

Although the process consumes energy and chemicals itself, it aligns with circular economy principles by looping chromium back into the tanning process, rather than releasing it as pollution.

Innovations in Leather Production

Conventional leather production involves intensive resource consumption, including substantial water usage and the application of hazardous chemicals, such as chromium salts, which lead to pollution and health risks.

Additionally, the process contributes to greenhouse gas emissions and generates considerable solid waste, with up to 70% of the wet weight of hides becoming waste during the tanning process.

Therefore, innovations in leather production are rapidly transforming the industry, driven by the need for sustainability, ethical practices, and environmental responsibility.

Here are some of the key innovations in leather production: 

Alternative Tanning Methods

Chrome tanning remains popular for its efficient stabilization of collagen and excellent leather qualities; however, it generates hazardous waste (e.g., chrome-laden sludge) and poses toxicity concerns.

To minimize the impact, leather manufacturers are using plant-derived tannins, organic/aldehyde tanning agents, and enzymatic or hybrid approaches.

1. Vegetable Tannins and Combination Tanning

Natural polyphenol tannins from plants (e.g., mimosa, quebracho, tara, chestnut) are classical chrome alternatives.

They produce durable leather with a distinctive look, though vegetable tanning is slower and traditionally yields a darker color.

A research study shows that chestnut tannin + THPS (tetrakis(hydroxymethyl) phosphonium sulfate) combination tannage is a fully chrome-free system.

Leather tanned with 20% chestnut extract, followed by 2% THPS, had a high shrinkage temperature (~95 °C) and physical strength on par with conventionally chrome-tanned leather.

As a result, the chestnut–THPS leather showed improved hydrothermal stability compared to using either chestnut or THPS alone, and its grain surface was clean (no unwanted deposits).

2. Aldehyde Tanning (Chrome-Free “Wet White”)

Aldehyde-based tanning agents (especially glutaraldehyde) have been widely used to produce chrome-free leathers, often called “wet white.”

Glutaraldehyde reacts with collagen to stabilize it, and aldehyde-tanned leathers are known for their light color and softness (making them useful for automotive and infant shoe leathers).

In practice, many “chrome-free” leathers today are made with glutaraldehyde or modified aldehydes, sometimes in combination with syntans (synthetic tannins) to improve leather performance.

3. Enzymatic and Biological Tanning

A research study explains that enzymatic tanning uses biodegradable enzymes to achieve the stabilizing cross-links, requiring less water and generating less waste compared to chrome processes.

This method aligns with the push for green chemistry in leather making, and it has the advantage of using renewable biocatalysts.

Lab-Grown and Plant-Based Leathers

Beyond improving animal-hide tanning, a parallel field of innovation is creating leather-like materials that do not require traditional hides.

Here are the key developments of lab-grown and plant-based leather:

1. Biofabricated Collagen Leather (Lab-Grown)

One cutting-edge approach produces real collagen (the primary protein in animal skin) through biotechnology and then assembles it into a leather-like material, essentially “growing” leather in the lab.

2. Mycelium Leather (Fungal Biomaterials)

Mycelium can grow rapidly on low-cost organic feedstock (such as agricultural waste), forming a mat of intertwined fibers that, when treated, resembles leather.

3.  Plant-Derived Leathers (Pineapple, Cactus, Apple, etc.)

Another category of innovation is the development of leather alternatives made from agricultural biomass and plant fibers. These materials typically use waste from farming or food production and transform it into a leather-like textile.

One well-known example is Piñatex, a material developed from pineapple leaf fibers.

Pineapple leaves (a byproduct of fruit farming) are rich in cellulose fiber; Piñatex processes these fibers into a non-woven mat, which is then infused with a resin to create a leather-like sheet.

4. Bacterial Cellulose and Other Biofabricated Materials

A distinct but related bio-alternative is bacterial cellulose leather. Certain bacteria (e.g., Acetobacter xylinum) can produce nanocellulose fibers when grown in sugary media (this is the substance in kombucha SCOBY).

This bacterial cellulose forms a robust pellicle that can be dried into a papery sheet. 

While they may not yet perfectly replicate all aspects of premium animal leather, they are increasingly close in performance for many uses. 

Advances in sustainable leather technologies

Advancements in sustainable leather technologies are transforming the industry by introducing eco-friendly alternatives and innovative production methods.

Leather manufacturers are exploring plant-based materials, such as pineapple leaves, mushrooms, and cacti, to create leather substitutes that reduce their environmental impact.

Here are the key advances in leather processing technology aimed at reducing environmental impact:

1. Water Conservation and Recycling

Leather making is water-intensive; it can require on the order of 30–40 m³ of water per ton of hides.

To maximize water reuse, many modern tanneries are also investing in advanced filtration and treatment systems.

Research shows membrane technologies (ultrafiltration, nanofiltration, reverse osmosis) are now commonly used to treat and recycle tannery wastewater.

These systems can remove dissolved salts and organic impurities, allowing water (and even some tanning chemicals, such as chromium) to be reclaimed for reuse.

2. Enzyme-Assisted and Cleaner Processing

Traditional dehairing uses sodium sulfide and lime to dissolve hair, a process that generates toxic hydrogen sulfide gas and a high pH effluent that requires treatment.

Enzyme-based unhairing uses proteolytic enzymes (and sometimes enzymes like keratinases) to break down the hair-anchoring proteins so that hair can be removed with little or no sulfide. 

One study found that an acid-active protease applied in pickling enabled the leather to subsequently uptake more chromium (or presumably any tanning agent) and resulted in better tanning fixation and deeper dye penetration.

3. Waste Valorization and Circular Economy

A research paper reveals that leather processing can generate up to 200 times more waste than the final product output.

To address this, various methods for recycling materials or energy from tannery waste, including chemical, thermal, and biological techniques.

These approaches aim to transform waste into valuable resources, such as recovering chromium, producing biofuels, or creating biodegradable materials, thereby aligning with the principles of the circular economy.

4. Renewable Energy and Emissions Reduction

To address the energy challenges, some large tanners have installed solar panels on their facilities to supply part of their electricity needs, or solar thermal systems to heat process water.

The study highlights that chromium recovery from leather waste represents a paradigm shift in waste management, offering significant potential for reducing harmful emissions and conserving resources.

The findings highlight the importance of integrating these sustainable technologies to minimize environmental impact and promote resource efficiency in the leather industry.

Frequently Asked Questions (FAQs)

Conclusion

Now that you know how leather is made, from the preservation of raw hides to the final finishing touches, it is clear that leather production plays an essential role for both consumers and industries alike.

Understanding the intricacies of leather production allows for informed decisions regarding the sourcing, use, and care of leather goods.

Additionally, awareness of the environmental and ethical considerations involved can guide choices toward more sustainable and responsible practices.

As the demand for eco-friendly materials grows, the leather industry is evolving to meet these expectations.

Innovations such as lab-grown and plant-based leathers are emerging as viable alternatives to traditional animal-derived leather.

These developments aim to reduce the environmental footprint of leather production while maintaining the quality and durability that consumers expect.

That said, while leather production remains a complex and time-honored craft, it is also an industry in transition.