Soy wax (fully hydrogenated soybean oil): SAP value and fatty acids
Soy wax (fully hydrogenated soybean oil) has a saponification value of 187.5 mg KOH/g. One gram needs 0.134 g of sodium hydroxide (NaOH) for bar soap or 0.188 g of potassium hydroxide (KOH) for liquid soap to turn fully into soap, before any superfat.
Key numbers
- SAP, NaOH
- 0.133666 g per g oil
- SAP, KOH
- 0.1875 g per g oil
- Saponification value
- 187.5 mg KOH/g
- INCI name
- Hydrogenated Soybean Oil
Example: 100 g of Soy wax (fully hydrogenated soybean oil) with no superfat needs 13.4 g of 100% NaOH, or 18.8 g of 100% KOH. A 5% superfat uses 5% less.
In soap
Its main fatty acids in our cited profile are stearic (86.8%) and palmitic (10.5%). The eight fatty acids used in soap-quality scores make up 98.9% of the profile.
On its own it scores 97 for hardness, 0 for cleansing and 2 for conditioning, with a saturated : unsaturated split of 97 : 2.
Container-candle soy wax often has additives (other waxes, blends of partly hydrogenated oil), so its lye need may differ. Use the supplier's COA for candle-grade wax. The NF range is wide.
Fatty-acid profile
| Fatty acid | % of fatty acids | Counts toward |
|---|---|---|
| lauric | 0% | hardness, cleansing, bubbly lather |
| myristic | 0% | hardness, cleansing, bubbly lather |
| palmitic | 10.5% | hardness, creamy lather |
| stearic | 86.8% | hardness, creamy lather |
| ricinoleic | 0% | conditioning, bubbly and creamy lather |
| oleic | 1.2% | conditioning |
| linoleic | 0.2% | conditioning |
| linolenic | 0.2% | conditioning |
Basis: USDA FDC SR Legacy 171440 (Oil, industrial, soy, fully hydrogenated), converted to % of total fatty acids.
Soap-quality scores (this oil alone)
| Hardness | 97 |
|---|---|
| Cleansing | 0 |
| Conditioning | 2 |
| Bubbly lather | 0 |
| Creamy lather | 97 |
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: 187.5 mg KOH/g (Midpoint of USP–NF Hydrogenated Vegetable Oil Type I range), from USP 32–NF 27, Hydrogenated Vegetable Oil monograph, Type I (via the drugfuture.com mirror of USP32), United States Pharmacopeial Convention. Printed value: 175 to 200 mg KOH/g.
Published values we checked:
- 175 to 200 mg KOH/g — United States Pharmacopeial Convention
- 175-200 mg KOH/g — Parchem Fine & Specialty Chemicals (distributor)
Fatty acids: USDA FoodData Central, SR Legacy 171440: Oil, industrial, soy, fully hydrogenated, USDA Agricultural Research Service.
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 .