Canola oil vs soybean oil in soap
Two cheap liquid oils, and soybean is the less stable: it carries 53.5 % linoleic acid against canola’s 22.5 %, and an iodine value of 132 against 116. Both keep best as a minor share, as in the bar below, where the swap moves linoleic and linolenic acid together from 12.6 % to 18.4 %. Soybean oil takes 2.4 % more lye, and the swap leaves the superfat at 5.4 %.
Rapeseed Oil - Low Erucic Acid (Canola Oil) Soya Bean Oil (Soybean Oil) Compare them with other oils
The published figures
| Canola oil | Soybean oil | |
|---|---|---|
| Saponification value, mg KOH/g | 182–193 | 189–195 |
| Used by the calculator, mg KOH/g | 187.5 (midpoint) | 192.0 (midpoint) |
| SAP for NaOH, g/g | 0.1337 | 0.1369 |
| Iodine value, g I₂/100 g | 105–126 | 124–139 |
| INS (SAP − IV) | 72 | 61 |
| Melting point, °C | — | — |
| Unsaponifiable matter, % | ≤ 2 | ≤ 1.5 |
| Name on a soap label | Sodium Canolate | Sodium Soyate |
Each oil alone
| Canola oil | Soybean oil | Usual range | |
|---|---|---|---|
| Hardness | 7 | 15 | 29–54 |
| Cleansing | 0 | 0 | 12–22 |
| Conditioning | 93 | 85 | 44–69 |
| Bubbly lather | 0 | 0 | 14–46 |
| Creamy lather | 7 | 14 | 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, soybean oil takes 2.4 % more lye than canola oil. For a kilogram of oil at a 5 % superfat, that is 127.0 g of sodium hydroxide for canola oil and 130.0 g for soybean oil.
In the bar below, where it is 20 % 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 |
|---|---|---|
| Canola oil | Soybean oil | 5.4 %barely moves |
| Soybean oil | Canola oil | 4.6 %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: 20 % of the one or the other, at a 5 % superfat, for 1,000 g of oils. The rest: 35 % olive oil, 25 % coconut oil, and 20 % shea butter.
| With canola oil | With soybean oil | Usual range | |
|---|---|---|---|
| Sodium hydroxide, g | 138.6 | 139.3 | |
| Hardness | 36 | 38 | 29–54 |
| Cleansing | 17 | 17 | 12–22 |
| Conditioning | 60 | 59 | 44–69 |
| Bubbly lather | 17 | 17 | 14–46 |
| Creamy lather | 19 | 21 | 16–48 |
| Iodine value | 65 | 68 | 41–70 |
| INS | 139 | 137 | 136–165 |
| Linoleic and linolenic acid, % | 12.6 | 18.4 |
Fatty-acid profile
| Fatty acid | Canola oil | Soybean oil | |
|---|---|---|---|
| Palmitic acid | C16:0 | 4.8 (2.5–7) | 10.8 (8–13.5) |
| Stearic acid | C18:0 | 1.9 (0.8–3) | 3.7 (2–5.4) |
| Oleic acid | C18:1 | 60.5 (51–70) | 23.5 (17–30) |
| Linoleic acid | C18:2 | 22.5 (15–30) | 53.5 (48–59) |
| α-Linolenic acid | C18:3 n-3 | 9.5 (5–14) | 7.8 (4.5–11) |
| Arachidic acid | C20:0 | 0.7 (0.2–1.2) | 0.4 (0.1–0.6) |
| Gadoleic acid | C20:1 | 2.2 (0.1–4.3) | 0.3 (0–0.5) |
| Erucic acid | C22:1 | 1.0 (0–2) | 0.2 (0–0.3) |
The figure the calculator uses for each oil, as a percentage of its fatty acids, with the published range in brackets.
Recipes with canola oil
- Budget lard and canola bar 25 % of the oils
- Indigo and annatto funnel pour bar 25 % of the oils
- Tomato and charcoal swirl bar 25 % of the oils
- White tea faux funnel pour bar 20 % of the oils
- Egg yolk feather swirl bar 17 % of the oils
- Supermarket oils bar 15 % of the oils
Guides
Other comparisons
Where these numbers come from
Rapeseed Oil - Low Erucic Acid (Canola 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.
Soya Bean Oil (Soybean 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.
JP XVIII 'Soybean Oil': acid value NMT 0.2; saponification value 188-195; unsaponifiable matter NMT 1.0 %; iodine value 126-140.