Walnut oil: SAP value and fatty acids
Walnut oil has a saponification value of 193 mg KOH/g. One gram needs 0.138 g of sodium hydroxide (NaOH) for bar soap or 0.193 g of potassium hydroxide (KOH) for liquid soap to turn fully into soap, before any superfat.
Key numbers
- SAP, NaOH
- 0.137586 g per g oil
- SAP, KOH
- 0.193 g per g oil
- Saponification value
- 193 mg KOH/g
- Iodine value
- 143
- INS
- 50
- INCI name
- Juglans Regia Seed Oil
Example: 100 g of Walnut oil with no superfat needs 13.8 g of 100% NaOH, or 19.3 g of 100% KOH. A 5% superfat uses 5% less.
In soap
Its main fatty acids in our cited profile are linoleic (55.6%) and oleic (23.3%). The eight fatty acids used in soap-quality scores make up 99.3% of the profile.
On its own it scores 10 for hardness, 0 for cleansing and 90 for conditioning, with a saturated : unsaturated split of 10 : 90.
High in linoleic acid; soft and goes rancid easily. Use at low levels. (Another study, of Pakistani walnuts in J. Mex. Chem. Soc. 2021, reported a value of 84 for one sample, which is not credible and was not used.) Published sources for this oil differ by more than 3%, so checking your supplier's certificate of analysis matters more than usual.
Fatty-acid profile
| Fatty acid | % of fatty acids | Counts toward |
|---|---|---|
| lauric | 0% | hardness, cleansing, bubbly lather |
| myristic | 0% | hardness, cleansing, bubbly lather |
| palmitic | 7.4% | hardness, creamy lather |
| stearic | 2.1% | hardness, creamy lather |
| ricinoleic | 0% | conditioning, bubbly and creamy lather |
| oleic | 23.3% | conditioning |
| linoleic | 55.6% | conditioning |
| linolenic | 10.9% | conditioning |
Basis: USDA FDC SR Legacy 171030 (Oil, walnut), converted to % of total fatty acids.
Soap-quality scores (this oil alone)
| Hardness | 10 |
|---|---|
| Cleansing | 0 |
| Conditioning | 90 |
| Bubbly lather | 0 |
| Creamy lather | 10 |
| Iodine | 143 |
| INS | 50 |
Each score adds up certain fatty acids, the way Soap Ledger scores a whole recipe. They are for comparing recipes; they don't predict how a bar will feel, and they say nothing about safety or skin.
Sources
SAP value: 193 mg KOH/g (Median of sources' mgKoh_mid, excluding the outlier study (see its note)), from Physical Properties of Fats and Oils (compiled from Ullmann's, Bailey's, AOCS and AFCEG handbooks), Deutsche Gesellschaft für Fettwissenschaft (DGF). Printed value: 189 - 198 mg KOH/g.
Published values we checked:
- 189 - 198 mg KOH/g — Deutsche Gesellschaft für Fettwissenschaft (DGF)
- 189 - 197 mg KOH/g — From Nature With Love (soap/cosmetic supplier)
- NaOH 0.1349 / KOH 0.19 g alkali per g oil — Certified Lye
- 171.6, 169.1, 167.6 (three cultivars) mg KOH/g — Springer (peer-reviewed, PMC open access)
Fatty acids and iodine: USDA FoodData Central, SR Legacy 171030: Oil, walnut, USDA Agricultural Research Service. Also checked: Springer (peer-reviewed, PMC open access) (Table 3, mean of three cultivars); Deutsche Gesellschaft für Fettwissenschaft (DGF) (Iodine value table).
NaOH and KOH values are converted from mg KOH/g with the molar masses 39.997 and 56.106 and rounded to 6 decimals, exactly as in the Soap Ledger app. Real oils vary by origin, grade and lot: check your supplier's certificate of analysis. Verify every weight before you make this, and follow lye safety. Not a safety or compliance certification.
Last updated .