Tannery Science in a Bottle – Simplified for Home Use
Leather Doctor® Kit A2 is a foundational 3-step care system designed for maintaining the health, beauty, and longevity of absorbent leathers. By replicating tannery wet-end processes—cleaning, hydration, fatliquoring, and protection—this kit keeps leather supple, strong, and protected from everyday wear.
It’s the smart homeowner’s solution for regular upkeep of aniline, vachetta, veg-tan, exotic, and other absorbent leathers that are prone to dryness and lose their softness.
1. Hydrator 3.3
Cleans, hydrates and relaxes dried, shrunken, or stiff leather fibers.
- Cleans gently without detergents while relaxing stiff or shrunken fibers.
- Acts as a fiber-reviving moisturizer at pH 3.3, preparing leather to absorb Fatliquor 5.0.
- Reverses dryness, cracking tendencies, and warped structure by restoring internal hydration.
2. Fatliquor 5.0
Softens and strengthens by replenishing fat and oil content lost to evaporation or neglect.
- The heart of leather conditioning—replenishes original fat and oil content lost through aging, heat, or neglect.
- Revives suppleness and tensile strength, preventing brittleness and cracking.
- Lubricates protein fibers, eliminating stiffness and “fiber squeaks.”
3. Protector B
Shields the leather from soiling, friction wear, and dye transfer with a buttery-feel non-stick finish.
- Provides a buttery-soft, non-stick shield against friction, soiling, and dye transfer.
- Makes leather easier to clean while enhancing touch comfort.
Available in a Plus version with added leather scent for freshness.
- Perfect for Regular Care – Keep leather in prime condition with a simple cycle: Clean → Hydrate → Soften → Protect.
- Ideal for Absorbent Leathers – Especially valuable for Vachetta that are prone to darkening, dryness, or body oil absorption.
When Neglect Turns Into a Restoration Need
Kit A2 is a maintenance system—but when leather has been neglected, heavily soiled, or lost its natural softness and beauty, the 6-bottle Kit A3 becomes the better choice.
Here’s why:
- Extra Cleaning Power – Kit A3 includes the Prep 4.4, formulated to safely remove heavier soil buildup aging conditioner and contamination that Hydrator 3.3 alone cannot.
- Prep 4.4 + Soft 3.8 + Rinse 3.0 Cycle – By pairing the advance cleaning system with Hydrator 3.3, A3 ensures that soils are flushed out completely, preventing reabsorption into the leather.
- Restoration-Level Care – Kit A3 goes beyond maintenance, actively restoring neglected leather back to showroom condition with a deeper cleaning + conditioning cycle.
Better Long-Term Results – For leathers already showing dryness, discoloration, or uneven absorption, A3 provides the corrective care that keeps them from permanent damage.
- Choose Kit A2 if your leather is in good shape and you want a simple routine for ongoing care.
- Choose Kit A3 if your leather has been ignored, is visibly soiled, or needs restoration before maintenance can be effective.
Think of Kit A2 as your everyday wellness plan, and Kit A3 as your restoration therapy when leather needs a reset.
✅ Kit A2 = Foundational Care → Clean, Hydrate, Soften, Protect.
✅ Kit A3 = Restorative Care → Deep Clean, Hydrate, Soften, Protect, Revive neglected leather.
Leather Doctor® puts tannery science in your hands—whether you need simple upkeep (Kit A2) or full restoration (Kit A3).
Easy to Use – Concentrates mix with 622g (0.7 quarts) distilled water, providing professional results in a homeowner-friendly format before use.
✅ Hydrator 3.3 (8oz concentrate)
✅ Fatliquor 5.0 (8oz concentrate)
✅ Protector B (8oz concentrate)
✅ Brush 1 (horsehair detail brush)
✅ Foam 2 (polyfoam applicator brush)
✅ Towel 5 (lint-free, reusable towel)
What It Is:
Hydrator 3.3 is a pH 3.3 water-based surfactant system. While not a detergents, it cleans deeper with its surfactant action helps it reduce surface and interfacial tension, enabling deeper and more uniform penetration and dispersion of moisture into the leather's internal fiber matrix.
What It Does:
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Surface Cleaning & Cleaning after Fatliquor 5.0
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Cleans leather mildly and removes surface residue after Fatliquor 5.0.
- Hydrates Dried & Shrunken Fibers - Leather that has dried without adequate fatliquor becomes stiff because collagen fibrils stick together. Hydrator 3.3 softens and reopens these tight, collapsed fibers, prepping them for fatliquoring.
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Facilitates Structural Realignment
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It acts as a “fiber-relaxer,” helping to reshape or realign leather that has become warped, wrinkled, or distorted.
- Reduces Surface Tension - The surfactant quality allows water to wet the leather thoroughly and uniformly, reducing patchy absorption and aiding in moisture migration into the hide structure.
- Suspends Soiling Residues - Residual soiling or foreign matter that has migrated into the leather during previous drying cycles can be suspended by the surfactant, allowing wick-up removal with a dry towel or absorption with tissue during the dwell stage.
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Prepares Leather for Fatliquoring -
It creates an open, hydrated channel within the leather for Fatliquor 5.0 to migrate in more effectively, mimicking the wet stage of the original tanning process.
- Tightens the leather's pH-sensitive protein fiber structure to maintain its integrity and dimensional stability.
- Restores the ionic (+ve) attraction between the leather collagen and the anionic (-ve) fatliquor molecules that follow, ensuring better bond and retention of fats and.
- After acidifying (with Acidifier 2.0) to relax the fiber structure
- During reshaping or stretch-forming for restoring wrinkled or misshapen panels
- For wick-up cleaning—to lift foreign contamination from within the leather (e.g., mold, soiling, or oxidized residues)
- To reverse stiffness or crack-formation tendencies from neglect or overexposure to high-alkaline cleaners
Summary:
Hydrator 3.3 is not just water—it’s a fiber-relaxing surfactant system that revives leather from within. It restores the leather’s absorbency and softness by decreasing surface tension, ensuring complete hydration, fiber separation, and better uptake of essential fatliquor.
It restores leather’s internal lubrication, flexibility, strength, and resilience—mimicking the essential fatliquoring stage in professional tanning and retanning processes.
Fatliquor 5.0 Key Benefits:
Lubricates and nourishes the leather structure
- Fatliquor 5.0 deposits fat and oil molecules that bond to the amphoteric protein fibers.
- These lubricate the fibrils, allowing them to slide over each other without stiffness, brittleness, or cracking.
Reinforces tensile strength and elasticity
- Proper fatliquoring prevents fiber embrittlement and maintains leather’s natural strength and softness.
Restores suppleness and prevents future damage
- Leather loses fatliquor over time due to aging, heat, sunlight, alkaline exposure, or cleaning.
- Replenishing it prevents shrinkage, stiffness, and cracks.
- Maintains leather’s dimensional stability and ability to flex without damage.
Tannery science basis:
- In the tannery, fatliquoring is one of the final and most critical stages after tanning and dyeing.
- It ensures that leather stays soft, strong, and flexible as it dries.
- The fats and oils form a molecular film around the protein fibers, acting as internal lubricants.
It ensures the leather is not just “looking good on the surface” but structurally rejuvenated from within.
Typical uses:
- Restoring dried, stiff, or shriveled leather.
- Rejuvenating leather after mold removal, alkaline contamination, or heat exposure.
- Conditioning leather during or after restoration, repairs, or refinishing.
Important note on process:
- Fatliquor 5.0 works only when the leather is properly hydrated first (with Hydrator 3.3) to relax the fiber structure and open it up for fatliquor absorption.
- Without hydration, fatliquor can’t penetrate deeply or bond uniformly — leading to incomplete restoration.
How Fatliquor 5.0 Works
- When applied, the water-encased fat and oil molecules penetrate deep into the leather fibers.
- As the water gradually evaporates, the fat and oil molecules hydrogen bond with the fibers, creating a breathable, flexible structure that enhances leather’s resilience and longevity.
- Proper fatliquoring ensures that leather retains its tensile strength, resists breakage, and maintains its natural softness, preventing premature aging and deterioration.
Leather Protector B by Leather Doctor® is a pH 3.2, non-stick, rub-resistant conditioner that enhances the durability of smooth leather while providing a soft, buttery feel.- Increases Wet & Dry Rub Resistance - Reduces stretch, scuffing, and wear.
- Enhances Durability - Creates a protective barrier against everyday friction.
- Prevents Sticky Soiling - Keeps dirt and stains from embedding into the leather.
- Resists Ink & Dye Transfer - Makes ballpoint ink and dye stains easier to remove.
- Reduces Friction Noise - Creates a quieter, smoother touch.
- Impart a Non-Sticky Surface - Reduces surface tackiness.
- Maintains Leather’s Breathability - Preserves natural softness and flexibility.
Protector B Plus offers all the benefits of Protector B with an added luxurious leather scent, making it an ideal choice for pastel leathers, helping them stay cleaner and stain-free for longer.
Regular use of Protector B ensures long-term protection, a smooth feel, and a refreshed leather appearance, making maintenance easier while extending the leather’s lifespan.
Brush 1 by Leather Doctor is a detailing horsehair brush designed for gentle, scratch-free cleaning on all smooth leathers.
- Soft Horsehair Bristles – Ensures safe cleaning without scratching or damaging leather surfaces
- Ergonomic Grooved Grip – Provides comfort and control for effortless detailing
- Sturdy & Durable Design – Built for long-term use in leather maintenance
- Ideal for Deep Pore Cleaning – Effectively loosens embedded dirt and grime without harming the finis
Foam 2 is a 2-inch high-density polyfoam brush designed for durable, precise, and smooth application of leather care products.
- High-Density Polyfoam – Resists tearing and shredding for long-lasting use
- Even Product Distribution – Ensures smooth, streak-free application
- Controlled Absorption – Holds and releases product efficiently for optimal coverage
- Versatile Use – Ideal for applying dyes, finishes, and conditioners on leather and sued
Towel 5 by Leather Doctor is a high-performance, lint-free paper towel designed to perform like cloth for efficient cleaning and drying without leaving residues
- Lint-Free – Leaves no fibers or residues behind
- Highly Absorbent – Quickly absorbed suspended soiling
- Stretchable & Durable – Strong enough for repeated use without tearing
- Washable & Reusable – Can be rinsed and reused for multiple application
1️⃣ Hydrator 3.3 concentrate 1: 25 is mixed with 218g distilled water or 1.5 inches from the top of the 8oz bottle before use.
2️⃣ It is applied to clean, rinse and hydrate to darken absorbent leathers.
3️⃣ Cleans with Brush 1 and rinse extract with Towel 5 until it shows clean.
4️⃣ Repeat application and distribution for a darkening appearance.
5️⃣ Allow 3-30 minutes to fully saturate and towel extract any wick soiling until it shows clean
6️⃣ Leather is manipulated and unnatural creases and wrinkles are stretched ready for Fatliquor 5.0.
1️⃣ Fatliquoring follows after Hydrator 3.3 with Fatliquor 5.0, Brush 1, Foam 2, and Towel 5.
2️⃣ Fatliquor 5.0 concentrate 1: 5 requires 189g of distilled water or mixing up to 1.5 inches below the 8oz bottle top before ready to use.
3️⃣ It is spread with Foam 2 and detailing with Brush 1 into the leather.
4️⃣ Repeat application between drying cycles until it absorbs no more.
5️⃣ Stretching and manipulating overstretches wrinkles to smartness.
6️⃣ The leather is left for slow natural drying for extra softness.
7️⃣ Surface strays are wiped with Hydrator 3.3 to be free of sticky residue.
1️⃣ Conditioning begins when leather is dry with Protector B, and Foam 2.
2️⃣ Protector B concentrate 1:19 is mixed with 217g distilled water or 1.5 inches from the top of the 8oz bottle before use.
3️⃣ Protector B is spread with Foam 2.
4️⃣ Leave to natural dry and ready for use.
Launched July 31, 2025 | August 9, 2025 by Roger Koh.
