Peanut oil in soap making
Published by The Soap Brain Team
Peanut oil is a conditioning soap-making oil rich in oleic acid (48%). A gram of it turns to soap with about 0.135 g of NaOH (lye). It makes a mild, gentle bar and pairs well with a harder, cleansing oil. Most soapers use it at 10–20% of their oils.
Fatty-acid profile
Peanut oil is a gentle, conditioning oil, mostly unsaturated fatty acids that leave a mild, moisturising bar with a softer, lower lather. It pairs naturally with a harder, more cleansing oil to firm the bar up and add bubbles. Because its polyunsaturated (linoleic/linolenic) share is on the higher side, watch the total across the whole recipe and consider a modest antioxidant to guard against rancidity and DOS.
Peanut oil is about 13% saturated fat and 76% unsaturated — that unsaturated majority is what makes it conditioning and slower to trace, but softer on its own.
| Fatty acid | Share | What it does in soap |
|---|---|---|
| Oleic acid | 48% | a monounsaturated fatty acid that makes a gentle, conditioning, moisturising bar with a slick, lower lather and a slower trace |
| Linoleic acid | 28% | a polyunsaturated fatty acid that is very conditioning but oxidises readily — a driver of DOS (dreaded orange spots) at high levels |
| Palmitic acid | 11% | a saturated fatty acid that builds a hard, long-lasting bar with a stable, creamy lather |
| Stearic acid | 2% | a saturated fatty acid that adds hardness and a thick, stable lather; a large share can speed up trace |
Peanut oil in the bar
Peanut oil gives a mild, low, slick lather on its own. Blended with a bubbly, cleansing oil it contributes body and mildness while the partner oil supplies the bubbles.
Peanut oil traces at a fairly typical pace; how fast the whole batch moves will depend mostly on the other oils, your temperatures and any fragrance you add.
In a blend Peanut oil is the conditioning, skin-feel component and can often make up the bulk of the oils. Add a firmer, more cleansing oil — coconut, palm or a hard butter — to bring hardness and bubbles the finished bar would otherwise miss.
Closest substitutes for Peanut oil
Out of Peanut oil? These oils behave most like it in a bar — ranked by how close their hardness, cleansing and conditioning profile and lye (SAP) requirement are. The numbers are predicted properties for a 100% single-oil bar, not a safety guide; always recalculate the lye when you swap an oil.
| Oil | Hardness | Cleansing | Conditioning | SAP (NaOH) |
|---|---|---|---|---|
| Peanut oil (this oil) | 13 | 0 | 76 | 0.135 |
| Argan oil | 13 | 0 | 80 | 0.135 |
| Sesame oil | 14 | 0 | 80 | 0.137 |
| Avocado oil | 17 | 0 | 80 | 0.133 |
| Wheat germ oil | 18 | 0 | 80 | 0.133 |
Using Peanut oil in a recipe
One gram of Peanut oil needs about 0.135 g of NaOH (sodium hydroxide) to turn fully to soap, within a documented range of 0.133–0.14 g/g across sources. The calculator below uses this value; always confirm the lye weight before you mix.
Its iodine value is about 94 — a higher value, pointing to a softer, more conditioning bar that is more prone to rancidity (DOS). Iodine value is only a rough guide, not a hard rule, but it gives you a feel for how a bar built around this oil will wear.
Most soapers use Peanut oil at roughly 10–20% of their oils.
Maker's note: Historic Marseille-style mild conditioning oil. Tree-nut/peanut allergen flag. It's sold as two quite different crops under one name — traditional cultivars run higher in linoleic, high-oleic ones much richer in oleic — so shelf life varies; our figures describe the common blend. About 7% of it is long-chain C20–C24 fat our numbers don't score, so it makes a slightly harder bar than the scores suggest.
Calculate lye for Peanut oil
The calculator below is pre-loaded with Peanut oil. Enter your weights, add other oils, and it works out the exact NaOH (lye) weight, water and quality numbers. Always weigh lye, oils and water — never measure by volume, wear gloves and eye protection, and add lye to water (never the reverse).
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Where these numbers come from
Every figure on this page is backed by at least two independent references, listed below — so you can check our work instead of taking our word for it.
- Codex Alimentarius CXS 210-1999 — Named Vegetable Oils (Tables 1–2) — SAP 187–196 mg KOH/g; Table 1 fatty acids: C16:0 8.0–14.0, C18:0 1.0–4.5, C18:1 35.0–69.0, C18:2 12.0–43.0, C18:3 ND–0.3, C14:0 ND–0.1, C20:0 1.0–2.0, C20:1 0.7–1.7, C22:0 1.5–4.5, C24:0 0.5–2.5
- Artiz Soap — SAP Value Table — SAP cross-check
- The Conscious Life — Peanut oil (USDA SR28) — oleic 44.8, palmitic 9.5, stearic 2.2, myristic 0.1 g per 100 g of oil — a ~95% basis, the glycerol backbone being the rest
- PMC9606997 — peanut-oil fatty acids (GC) — stearic 1.62–1.78; and the C20–C24 tail: behenic 1.96–2.43, arachidic 0.77–0.94, gadoleic 1.19–1.36, lignoceric 0.77–1.12
SAP data last updated · 51 oils covered.
Peanut oil soap FAQ
- Can you make soap with 100% Peanut oil?
- It is not recommended. Peanut oil shows its best in a blend, usually up to about 20% of the oils. On its own the bar would be unbalanced — too soft or low-lathering for everyday use.
- What superfat should I use with Peanut oil?
- A 5% superfat is a safe, common starting point for recipes using Peanut oil; adjust to taste once you know how the finished bar feels. Never drop to 0% or below without a deliberate reason — the calculator will ask you to confirm it.
- Does Peanut oil speed up or slow down trace?
- Peanut oil traces at a fairly typical pace; how fast the whole batch moves will depend mostly on the other oils, your temperatures and any fragrance you add.