🧼 Goat Milk Soap Recipe Calculator
Recipe Breakdown
How to Use This Tool
Start by entering your total oil weight and selecting the unit (grams, ounces, or pounds). Choose a preset oil blend or select Custom Blend to input your own SAP value for specialty oil mixes.
Select your lye type: Sodium Hydroxide (NaOH) for bar soap, or Potassium Hydroxide (KOH) for liquid soap. Adjust the superfat percentage (5-10% is standard for mild bars) and liquid ratio (100% means equal weight of goat milk to lye).
Add an optional fragrance or essential oil load if desired, then click Calculate Recipe to see your full ingredient breakdown. Use the Reset button to clear all fields, or Copy Results to save your recipe.
Formula and Logic
This calculator uses standard saponification (SAP) values to determine lye requirements. The core formula for lye weight is:
Lye Weight = Total Oil Weight × SAP Value × (1 - Superfat Percentage)
Goat milk weight is calculated as a percentage of the total lye weight, based on your selected liquid ratio. All ingredient weights are converted to your chosen unit for consistency.
For preset oil blends, SAP values are averaged based on standard industry values for cold process soap making. Custom blends use your manually entered SAP value to ensure accuracy for specialty oil mixes.
Practical Notes
Always wear gloves and eye protection when handling lye, as it is a corrosive substance. Add lye to goat milk slowly (never the reverse) to avoid scorching the milk.
Fresh goat milk works best for cold process soap, but reconstituted powdered goat milk is a shelf-stable alternative. Reduce liquid ratio to 70-80% for harder, longer-lasting bars.
Superfat percentages above 10% may cause soap to become soft or develop a rancid smell over time. Test small batches first when adjusting new recipes.
Store finished goat milk soap in a cool, dry place for 4-6 weeks to cure before use. This allows excess moisture to evaporate and the soap to harden fully.
Why This Tool Is Useful
Home soap makers often struggle to scale recipes for different batch sizes, or adjust for custom oil blends. This tool eliminates manual calculation errors that can ruin batches.
It accounts for key variables like superfat and liquid ratio, which directly impact soap quality, mildness, and shelf life. Both hobbyists and small-scale home producers can use it to standardize recipes.
The detailed breakdown includes individual oil weights for preset blends, so you don’t have to calculate sub-ingredients manually. Copy functionality lets you save recipes to your notes or planner easily.
Frequently Asked Questions
Can I use this calculator for melt-and-pour goat milk soap?
No, this tool is designed for cold process soap making using lye. Melt-and-pour bases already contain saponified oils, so no lye calculation is needed.
What if my goat milk scorches when adding lye?
Freeze goat milk into ice cubes before adding lye to slow the temperature rise. You can also split the liquid, using half goat milk and half distilled water to reduce scorching risk.
How do I find the SAP value for custom oils?
Check the supplier’s specification sheet for your oil, or refer to standard saponification value charts for common soap making oils. SAP values are typically listed per gram of oil.
Additional Guidance
Scale recipes up or down using the batch size input: enter 500 for a small test batch, or 5000 for a larger production run. All other values adjust automatically.
If using essential oils, check safe usage rates for skin contact. Citrus oils may cause photosensitivity, so limit loads to 1-2% for leave-on soap products.
Label finished soap with ingredients and the production date. Cured soap stored properly will last 12-18 months, but soap with high superfat may have a shorter shelf life.