Castor Oil
INCI Ricinus Communis Seed Oil. Saponified with NaOH it is listed as Sodium Castorate, with KOH as Potassium Castorate. CAS 8001-79-4; EC 232-293-8, as CosIng gives them. Also: Ricinus communis seed oil, Oleum ricini, Ricinus oil.
Published values
| Saponification value | 176–182 mg KOH/g |
| Used by the calculator | 179.0 mg KOH/g (midpoint) |
| SAP for NaOH | 0.1276 g/g |
| Iodine value | 83–88 g I₂/100 g |
| INS (SAP − IV) | 94 |
| Melting point | — |
| Unsaponifiable matter | ≤ 0.8 % |
Soapmaking books print about 0.129 g NaOH per g (median of 11 books), which agrees with ours to within 2 %.
A bar made of 100 % Castor Oil
Conventional qualities summed from the fatty-acid groups; a single-oil bar is a reference point, not a recipe.
How much lye
| Oil | NaOH | KOH |
|---|---|---|
| 500 g | 60.6 g(59.6–61.6) | 85.0 g(83.6–86.5) |
| 1 kg | 121.2 g(119.2–123.3) | 170.1 g(167.2–172.9) |
| 1 lb (454 g) | 55.0 g(54.1–55.9) | 77.1 g(75.8–78.4) |
| 2 lb (907 g) | 110.0 g(108.1–111.8) | 154.3 g(151.7–156.9) |
For this oil alone at 5 % superfat, with pure sodium hydroxide (NaOH) or pure potassium hydroxide (KOH); in brackets, across the published range of its saponification value. KOH is usually sold at 90 %: divide by 0.9. For a whole recipe, open the calculator.
Fatty-acid profile
Saturated : unsaturated 4 : 96
| Fatty acid | Published range, % | Used | |
|---|---|---|---|
| Palmitic acid | C16:0 · saturated | ≤ 2 | 2.0 |
| Stearic acid | C18:0 · saturated | ≤ 2.5 | 2.5 |
| Oleic acid | C18:1 | 2.5–6 | 4.3 |
| Ricinoleic acid | C18:1-OH | 85–92 | 88.5 |
| Linoleic acid | C18:2 | 2.5–7 | 4.8 |
| α-Linolenic acid | C18:3 n-3 | ≤ 1 | 1.0 |
| Gadoleic acid | C20:1 | ≤ 1 | 1.0 |
Recipes that use it
- Transparent glycerin bar 30 % of the oils
- Beer and castor shampoo bar 20 % of the oils
- Liquid hand soap 20 % of the oils
- Liquid shampoo 20 % of the oils
- Shampoo bar for normal to oily hair 20 % of the oils
- Kukui and almond shampoo bar 19 % of the oils
- Coconut liquid dish soap 15 % of the oils
- Coconut liquid hand soap 15 % of the oils
- High-castor lather bar 15 % of the oils
- Liquid body wash 15 % of the oils
- Nettle shampoo bar 15 % of the oils
- Unscented shampoo bar 15 % of the oils
Guides that discuss it
Where these numbers come from
Specific gravity 0.957-0.961; free fatty acids NMT 3.5 mL 0.10 N NaOH per 10 g; hydroxyl value 160-168; iodine value 83-88; saponification value 176-182.
Mirror site hosting the USP 29-NF 24 text; values transcribed from that page. Newer USP editions may differ.
JP XVIII 'Castor Oil': specific gravity 0.953-0.965; acid value NMT 1.5; saponification value 176-187; hydroxyl value 155-177; iodine value 80-90.
Fatty-acid limits are those of the Ph. Eur. 12 monograph 'Castor oil, refined' as stated by the producer.
SAP 176-182, IV 83-88, hydroxyl value 160-168 and specific gravity 0.957-0.961 from the USP 35 'Castor Oil' monograph (USP 29 gives the same limits). JP XVIII 'Castor Oil' (Oleum Ricini): SAP 176-187, hydroxyl value 155-177, IV 80-90, acid value NMT 1.5, specific gravity 0.953-0.965. Fatty-acid composition and unsaponifiable (max 0.8 %) are the Ph. Eur. 12 'Castor oil, refined' limits as transcribed on the Gustav Heess specification sheet (GC of FAMEs, Ph. Eur. 2.4.22): palmitic max 2.0, stearic max 2.5, oleic (+isomer) 2.5-6.0, linoleic 2.5-7.0, linolenic max 1.0, eicosenoic max 1.0, ricinoleic 85.0-92.0, any other FA max 1.0 %; hydroxyl value min 160 mg KOH/g. Ph. Eur. prints no SAP/IV for castor oil. Hydroxyl-bearing ricinoleic acid gives soap its characteristic solubility; density/viscosity data in the sources.
This record is part of the open ingredient database (ODbL), which you can download as CSV or JSON. Found an error or a better primary source? Corrections with a link to the document are welcome at support@soapformulator.com.