Olive oil vs rice bran oil in soap
Faiola and Grosso both suggest rice bran oil in place of olive oil to cut the cost. It is one of the heavier liquid oils, with more palmitic acid, and it carries up to 6.5 % unsaponifiable matter. The catch is its linoleic acid, 31.5 % against 12.3 %, which shortens shelf life at a large share. The two take almost the same lye, so a swap leaves the bar below at 4.9 % superfat.
Olive Oil (virgin / refined / olive oil) Rice Bran Oil Compare them with other oils
The published figures
| Olive oil | Rice bran oil | |
|---|---|---|
| Saponification value, mg KOH/g | 184–196 | 180–199 |
| Used by the calculator, mg KOH/g | 190.0 (midpoint) | 189.5 (midpoint) |
| SAP for NaOH, g/g | 0.1354 | 0.1351 |
| Iodine value, g I₂/100 g | 75–94 | 90–115 |
| INS (SAP − IV) | 106 | 87 |
| Melting point, °C | — | — |
| Unsaponifiable matter, % | ≤ 1.5 | ≤ 6.5 |
| Name on a soap label | Sodium Olivate | Sodium Ricebranate |
Each oil alone
| Olive oil | Rice bran oil | Usual range | |
|---|---|---|---|
| Hardness | 17 | 22 | 29–54 |
| Cleansing | 0 | 1 | 12–22 |
| Conditioning | 82 | 76 | 44–69 |
| Bubbly lather | 0 | 1 | 14–46 |
| Creamy lather | 17 | 21 | 16–48 |
A single oil’s hardness, cleansing and the rest are the same sums the calculator shows for a recipe, applied to that one oil. They explain what the oil brings to a blend; they do not predict how a soap of only that oil would feel.
Swapping one for the other
Gram for gram, rice bran oil takes 0.3 % less lye than olive oil. For a kilogram of oil at a 5 % superfat, that is 128.7 g of sodium hydroxide for olive oil and 128.3 g for rice bran oil.
In the bar below, where it is 45 % of the oils, weigh the lye for one and put in the other without recalculating, and the superfat moves:
| Lye weighed for | Oil used | Superfat |
|---|---|---|
| Olive oil | Rice bran oil | 4.9 %barely moves |
| Rice bran oil | Olive oil | 5.1 %barely moves |
The superfat is the share of the oils the lye leaves unsaponified, planned here at 5 %; below zero, there is more lye than the oils can take. Put the oil you actually have in the lye calculator and it works out the lye for that oil.
The same bar with either
The bar: 45 % of the one or the other, at a 5 % superfat, for 1,000 g of oils. The rest: 25 % coconut oil, 25 % shea butter, and 5 % castor oil.
| With olive oil | With rice bran oil | Usual range | |
|---|---|---|---|
| Sodium hydroxide, g | 138.4 | 138.2 | |
| Hardness | 39 | 41 | 29–54 |
| Cleansing | 17 | 17 | 12–22 |
| Conditioning | 57 | 55 | 44–69 |
| Bubbly lather | 21 | 22 | 14–46 |
| Creamy lather | 26 | 28 | 16–48 |
| Iodine value | 58 | 66 | 41–70 |
| INS | 147 | 138 | 136–165 |
| Linoleic and linolenic acid, % | 8.1 | 17.1 |
Fatty-acid profile
| Fatty acid | Olive oil | Rice bran oil | |
|---|---|---|---|
| Myristic acid | C14:0 | 0.0 (0–0.05) | 0.5 (0–1) |
| Palmitic acid | C16:0 | 13.8 (7.5–20) | 18.5 (14–23) |
| Palmitoleic acid | C16:1 | 1.9 (0.3–3.5) | 0.3 (0–0.5) |
| Stearic acid | C18:0 | 2.8 (0.5–5) | 2.5 (0.9–4) |
| Oleic acid | C18:1 | 69.0 (55–83) | 43.0 (38–48) |
| Linoleic acid | C18:2 | 12.3 (3.5–21) | 31.5 (21–42) |
| α-Linolenic acid | C18:3 n-3 | 0.6 (0–1.2) | 1.5 (0.1–2.9) |
| Behenic acid | C22:0 | 0.1 (0–0.2) | 0.5 (0–1) |
The figure the calculator uses for each oil, as a percentage of its fatty acids, with the published range in brackets.
Recipes with olive oil
- Castile brine bar 100 % of the oils
- Castile soap 100 % of the oils
- Liquid castile soap 100 % of the oils
- Nablus-style olive oil soap 100 % of the oils
- Savon noir, olive soft soap 100 % of the oils
- Greek olive bar 90 % of the oils
Recipes with rice bran oil
- Rice bran and avocado bar 30 % of the oils
- Indigo and annatto funnel pour bar 25 % of the oils
- Nettle and yarrow split bar 25 % of the oils
- Soap scrap confetti bar 23 % of the oils
- Madder root ombre bar 20 % of the oils
- Lemon, annatto and cocoa linear swirl bar 16 % of the oils
Guides
Other comparisons
Where these numbers come from
Olive Oil (virgin / refined / olive oil)
Section 3 fatty-acid composition (GC, % total FA) is mandatory. Appendix 3 'Chemical and physical characteristics' (relative density 0.910-0.916, saponification value, iodine value (Wijs), unsaponifiable matter) is ADVISORY. C18:3 limit left open in this print (footnote 3: national limits may remain pending IOOC survey).
JP XVIII 'Olive Oil': acid value NMT 1.0; saponification value 186-194; unsaponifiable matters NMT 1.5 %; iodine value 79-88; specific gravity 0.908-0.914.
Ph. Eur. 12 'Olive oil, refined' fatty-acid limits, including linolenic acid max 1.2 %: the source of the record's linolenic range, which CXS 33 leaves open.
Rice Bran Oil
Verbatim mirror of the FAO file CXS_210e.pdf; the official FAO link (https://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%3A%2F%2Fworkspace.fao.org%2Fsites%2Fcodex%2FStandards%2FCXS%2B210-1999%2FCXS_210e.pdf) was Cloudflare-gated at retrieval. Table 1 (Section 3.1) = mandatory GLC fatty-acid ranges, % of total fatty acids, ND = not detectable (<=0.05%). Table 2 (Appendix 'Other quality and composition factors') gives saponification value, iodine value (Wijs) and unsaponifiable matter of CRUDE oils; the Appendix is explicitly ADVISORY (a product not meeting it may still conform). This print predates the 2021-2025 amendments; the 2024 additions (avocado, camellia seed, sacha inchi, high-oleic soya bean) are not included.