Walnut oil in soap making
Published by The Soap Brain Team
Walnut oil is a conditioning soap-making oil rich in linoleic acid (58%). A gram of it turns to soap with about 0.137 g of NaOH (lye). It makes a mild, gentle bar and pairs well with a harder, cleansing oil. Most soapers use it at 5–15% of their oils.
Fatty-acid profile
Walnut 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.
Walnut oil is about 7% saturated fat and 88% 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 |
|---|---|---|
| Linoleic acid | 58% | a polyunsaturated fatty acid that is very conditioning but oxidises readily — a driver of DOS (dreaded orange spots) at high levels |
| Oleic acid | 20% | a monounsaturated fatty acid that makes a gentle, conditioning, moisturising bar with a slick, lower lather and a slower trace |
| Linolenic acids (C18:3) | 10% | the polyunsaturated C18:3 family — deeply conditioning but the most prone to rancidity; keep the combined polyunsaturated total modest |
| Palmitic acid | 7% | a saturated fatty acid that builds a hard, long-lasting bar with a stable, creamy lather |
Walnut oil in the bar
Walnut 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.
Walnut 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 Walnut 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 Walnut oil
Out of Walnut 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) |
|---|---|---|---|---|
| Walnut oil (this oil) | 7 | 0 | 88 | 0.137 |
| Hemp seed oil | 6 | 0 | 86 | 0.137 |
| Sweet almond oil | 7 | 0 | 86 | 0.136 |
| Hazelnut oil | 5 | 0 | 88 | 0.135 |
| Camellia / tea seed oil | 9 | 0 | 90 | 0.136 |
Using Walnut oil in a recipe
One gram of Walnut oil needs about 0.137 g of NaOH (sodium hydroxide) to turn fully to soap, within a documented range of 0.136–0.138 g/g across sources. The calculator below uses this value; always confirm the lye weight before you mix.
Its iodine value is about 150 — 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 Walnut oil at roughly 5–15% of their oils.
Maker's note: Mild conditioning; PUFA-heavy — minor oil, watch shelf life (DOS risk).
Calculate lye for Walnut oil
The calculator below is pre-loaded with Walnut 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.
- From Nature With Love — Saponification Chart — SAP range
- Artiz Soap — SAP Value Table — SAP cross-check
- PubMed — nut oil fatty-acid study — fatty-acid profile
SAP data last updated · 51 oils covered.
Walnut oil soap FAQ
- Can you make soap with 100% Walnut oil?
- It is not recommended. Walnut oil shows its best in a blend, usually up to about 15% 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 Walnut oil?
- A 5% superfat is a safe, common starting point for recipes using Walnut 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 Walnut oil speed up or slow down trace?
- Walnut 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.