Cold-Process Saponification & In-Situ Glycerin Retention Engineering Runbook

1. Chemical Reaction & Glycerin Retention

During Cold-Process Saponification, one mole of plant triglyceride reacts with three moles of sodium hydroxide (NaOH) to yield three moles of fatty acid salt (true soap) plus one mole of natural plant glycerin:

Triglyceride (Coconut / Shea Oils) + 3 NaOH  ───►  3 R-COONa (Artisan Soap) + C₃H₅(OH)₃ (Natural Plant Glycerin)

Industrial triple-milled soap factories salt-out and vacuum-distill this glycerin out of the soap kettle to sell into higher-margin cosmetics. FtaaE retains 100% of the endogenous plant glycerin inside every bar.

2. Cold-Process Stage Parameters

| Process Stage | Target Temperature | Target Duration | Critical Process Control Parameter |

| :--- | :--- | :--- | :--- |

| 1. Lye Solution Cooling | 38.0°C ± 2.0°C | 45 min | Dissolve in purified water (< 5 ppm TDS) to prevent metallic soap scum |

| 2. Lipid Base Tempering | 40.0°C ± 2.0°C | 20 min | Melt raw shea butter gently to prevent stearic acid graininess |

| 3. Emulsification to Light Trace | 41.5°C | 4–6 min | Low-shear immersion blending to prevent air micro-cavities |

| 4. Botanical Clay & EO Fold-In | 39.0°C | 2 min | Anchor essential oils in kaolin or French green clay slurry |

| 5. Saponification & Wire Cut | 48°C peak -> 22°C | 24 hours | Ultrasonic/tensioned stainless wire cut at Shore OO hardness > 72 |

| 6. Dehumidified Cure Rack | 20.5°C @ 40% RH | 28–35 days | Crystalline beta-phase soap network formation & water evaporation |

3. Batch Formulation Verification Checklist

• Verify dual-scale mass check on both lipid phase (± 1 g) and NaOH alkali charge (± 0.1 g).
• Pre-disperse mineral clays (Rose Kaolin, French Green Clay, Bentonite) in 2x weight of botanical oil prior to trace.
• Record 7-day, 14-day, 21-day, and 28-day bar weight loss curve until mass stabilizes at ≥ 128 g (4.5 oz).
• Perform final surface inspection and pack into breathable paperboard unit cartons.