Beeswax: SAP value and fatty acids
Beeswax has a saponification value of 90 mg KOH/g. One gram needs 0.064 g of sodium hydroxide (NaOH) for bar soap or 0.090 g of potassium hydroxide (KOH) for liquid soap to turn fully into soap, before any superfat.
Key numbers
- SAP, NaOH
- 0.064159 g per g oil
- SAP, KOH
- 0.09 g per g oil
- Saponification value
- 90 mg KOH/g
- INCI name
- Cera Alba
Example: 100 g of Beeswax with no superfat needs 6.4 g of 100% NaOH, or 9.0 g of 100% KOH. A 5% superfat uses 5% less.
In soap
Beeswax is left out of the soap-quality scores in Soap Ledger: it is mostly not ordinary oil (a wax, resin, blend or an oil with unusual fatty acids), so those scores would not describe it. It still counts fully in the lye calculation.
A wax, not a triglyceride: mostly long-chain esters plus hydrocarbons, with a lot of unsaponifiable matter. Only part becomes soap; treat it as a hardener and keep it to a few percent. Published sources for this oil differ by more than 3%, so checking your supplier's certificate of analysis matters more than usual.
Sources
SAP value: 90 mg KOH/g (Midpoint of JP18 pharmacopoeia range), from The Japanese Pharmacopoeia, 18th ed. (English), Crude Drugs and Related Drugs monographs, Ministry of Health, Labour and Welfare (Japan). Printed value: 80 – 100 mg KOH/g.
Published values we checked:
- 80 – 100 mg KOH/g — Ministry of Health, Labour and Welfare (Japan)
- NaOH 0.0689 / KOH 0.0970 g alkali per g oil — Certified Lye
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.
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