Help Me Pick Oils — Liquid Soap (KOH) Wizard
How SoapMath Recommends Oils for Your KOH Liquid Soap Recipe
Liquid soap uses different oil logic than bar soap. The same oils that make a hard, long-lasting bar (tallow, palm, cocoa butter) can cause cloudiness and separation in a KOH liquid soap. The Help Me Pick Oils wizard in the liquid soap calculator is designed specifically for KOH formulation — it recommends a foam oil, a base oil, and optionally castor oil based on four questions about your desired soap qualities.
This guide explains each step and what the five KOH quality scores mean — so you can understand why the wizard recommends what it does and make confident manual adjustments.
How to Use the Wizard
- Select KOH in the Soap Calculator lye type, then click "Help Me Pick Ingredients" above the oil list.
- Step 1: Clarity — Choose whether you want a clear, slightly hazy, or opaque/cream soap.
- Step 2: Lather — Choose bubbly, balanced, or creamy/mild foam.
- Step 3: Conditioning — Choose how skin feels after washing.
- Step 4: Gentleness — Choose mild/sensitive, balanced, or deep clean.
- Restrictions — Optionally toggle Vegan Only or Nut-Free on the last preference screen.
- Pick Foam Oil — Select one from up to 5 ranked candidates.
- Pick Base Oil — Select one from up to 5 ranked candidates.
- Add Castor Oil? — Recommended yes. Boosts lather and reduces clarity risk.
- Review & Add — Click "Add Oils to Recipe" to load them without percentages.
After adding oils, use Help Me Pick % to set optimal ratios based on the same preferences — they share your answers automatically.
The Five KOH Quality Scores
Every oil in the database has a calculated fatty acid profile. The wizard uses five liquid-soap-specific scores — not the bar soap scores (hardness, INS, iodine) — because liquid soap behaves completely differently. Each score is a weighted sum of relevant fatty acids, expressed as a number from roughly 0–100.
SoapMath exclusive: These five KOH quality scores and the formulas behind them were developed by SoapMath. They don't appear in standard soap-making references — they were purpose-built for KOH liquid soap formulation.
Cleansing
Formula: Lauric acid % + Myristic acid %
Measures how effectively the soap removes oils, dirt, and sebum from skin. Lauric and myristic are the only fatty acids that produce meaningful cleansing action — the same mechanism that creates big bubbles.
Values above the target can be drying on sensitive skin. Values below produce a very mild but low-lathering soap.
Lather
Formula: Cleansing + Ricinoleic acid %
Lather combines cleansing power (volume and fluffiness from lauric/myristic) with the stability and creaminess that ricinoleic acid (castor oil) contributes. A soap can have moderate cleansing but excellent lather if castor oil is in the recipe.
This is why castor oil raises lather without raising cleansing — ricinoleic acid adds directly to lather but doesn't appear in the cleansing score.
Mildness
Formula: Oleic acid % + Ricinoleic acid % + Linoleic acid %
Mildness reflects how conditioning and skin-friendly the soap is. These unsaturated fatty acids don't strip the skin's natural oils the way lauric/myristic does. Oils high in oleic (olive, avocado, canola) score very high on mildness.
Note: mildness and cleansing trade off against each other — the same recipe can't maximize both.
Clarity Risk
Formula: max(0, Palmitic% + Stearic% − 0.25 × Ricinoleic% − 0.10 × Oleic%)
Palmitic and stearic acid are solid at room temperature — they cause cloudiness, gel lumps, and separation in liquid soap. Ricinoleic and oleic acid partially offset this by increasing solubility. The clarity risk score estimates how much of the hard fat is left "unchecked" after these offsets.
Coconut oil's moderate clarity risk (palmitic ~9%, stearic ~3%) is offset by its high ricinoleic partner (castor) and justified by its cleansing contribution. Palm oil (~44% palmitic) has very high clarity risk.
Dilution Ease
Formula: Cleansing (Lauric+Myristic) + Oleic + Ricinoleic
Dilution ease predicts how readily the finished soap paste will dissolve in water when you dilute it. Oils high in lauric, oleic, and ricinoleic acids produce more water-soluble potassium soaps. High-palmitic or high-stearic oils produce less soluble soaps that may require heat and stirring to fully dissolve.
The Four Preference Steps
Step 1: Clarity
Replaces "hardness" from bar soap. Controls how strictly the wizard filters for clarity-safe oils and penalizes high-clarity-risk ingredients.
Step 2: Lather
Controls which oils qualify for the foam oil slot and what cleansing/lather target ranges apply.
Step 3: Conditioning
Drives the mildness target range for the base oil slot. The base oil is the backbone of your formula — usually 55–75% of the recipe.
Step 4: Gentleness
Cross-cuts all slots — shifts the cleansing and lather target ranges up or down across the whole recipe.
The Conflict: Big Bubbles + Gentle
Big Bubbles and Gentle are mutually exclusive. Big bubbly lather requires a high-lauric foam oil — the same lauric acid that drives cleansing strength. A gentle formula minimizes lauric acid to protect sensitive skin. Asking for maximum bubbles and maximum gentleness at the same time is contradictory.
When Big Bubbles is selected → Gentle is grayed out (falls back to Balanced). When Gentle is selected → Big Bubbles is grayed out (falls back to Balanced).
These are the only two hard-blocked options. All other combinations (including Clear + Moisturizing, Bubbly + Balanced gentleness, or Creamy + Deep Clean) are allowed.
The Three Oil Slots
Foam Oil — The Lather Driver
High in lauric and myristic acid. Creates cleansing power and foam volume. Typically 15–25% of the final recipe. Examples: Coconut Oil (cleansing 66), Babassu Oil (cleansing 54), Palm Kernel Oil (cleansing 53). Up to 5 candidates ranked by your preferences.
Base Oil — The Conditioning Foundation
High in oleic, linoleic, and/or ricinoleic acid. Low clarity risk. Makes the soap mild and skin-friendly. Typically 55–75% of the final recipe. Examples: Olive Oil (mildness 85, clarity risk 1), Sunflower Oil (mildness 80, clarity risk 2), Canola Oil (mildness 65, clarity risk 2). Up to 5 candidates ranked by your preferences.
Castor Oil — The Lather Booster (Optional)
Always added at around 5–10%. Ricinoleic acid (cleansing 0, lather boost, mildness 90, clarity risk −4 net) improves lather without raising cleansing. Unique among liquid soap oils — recommended for virtually every recipe.
Starting Percentages After the Wizard
The wizard adds oils without percentages. A typical starting point:
| Oil slot | Suggested start | Notes |
|---|---|---|
| Foam oil (coconut) | 20% | Increase to 30% for more lather |
| Base oil (olive) | 73% | Fills the rest after castor |
| Castor oil | 7% | Max 10% — too much = sticky |
Use Help Me Pick % to let the optimizer calculate the best ratios automatically — it uses the same preferences you already set.
Frequently Asked Questions
Try the Liquid Soap Oil Wizard
Select KOH in the Soap Calculator to access Help Me Pick Ingredients for liquid soap.