Stearic acid (palm-based) in soap making
Published by The Soap Brain Team
Stearic acid (palm-based) is a hardening soap-making oil rich in stearic acid (100%). A gram of it turns to soap with about 0.149 g of NaOH (lye). It firms up a bar with a stable, creamy lather and blends well with conditioning oils. Most soapers use it at 1–5% of their oils.
Fatty-acid profile
Stearic acid (palm-based) is mainly a hardening oil: its saturated fatty acids give a firm, long-lasting bar with a stable, creamy lather, and it is usually blended with more conditioning oils to keep the finished soap mild.
Stearic acid (palm-based) is about 100% saturated fat and 0% unsaturated — that saturated majority is what lets it firm up a bar and hold a stable lather.
| Fatty acid | Share | What it does in soap |
|---|---|---|
| Stearic acid | 100% | a saturated fatty acid that adds hardness and a thick, stable lather; a large share can speed up trace |
Stearic acid (palm-based) in the bar
Expect a dense, low-bubble, creamy lather from Stearic acid (palm-based) — rich and steady rather than foamy. Pairing it with a bubbly oil adds the fluffy bubbles it lacks.
Because it is rich in palmitic and stearic acids, Stearic acid (palm-based) tends to bring a batch to trace quickly and set up fast, so work briskly and keep fragrances that accelerate trace in mind. The upside is a firm bar that usually unmoulds within a day or two.
In a blend Stearic acid (palm-based) is a hardening, bar-firming component. Use it in small amounts; combine it with conditioning liquid oils so the bar stays mild rather than brittle.
Closest substitutes for Stearic acid (palm-based)
Out of Stearic acid (palm-based)? 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) |
|---|---|---|---|---|
| Stearic acid (palm-based) (this oil) | 100 | 0 | 0 | 0.149 |
| Cocoa butter | 62 | 0 | 38 | 0.137 |
| Illipe butter | 61 | 0 | 38 | 0.135 |
| Kokum butter | 59 | 0 | 38 | 0.134 |
| Sal butter | 51 | 0 | 40 | 0.132 |
Using Stearic acid (palm-based) in a recipe
One gram of Stearic acid (palm-based) needs about 0.149 g of NaOH (sodium hydroxide) to turn fully to soap, within a documented range of 0.145–0.152 g/g across sources. The calculator below uses this value; always confirm the lye weight before you mix.
Its iodine value is about 0 — a low value, pointing to a hard, long-lasting bar with good shelf life. 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 Stearic acid (palm-based) at roughly 1–5% of their oils.
Maker's note: Isolated saturated fatty acid used as a hardening/trace-speed additive — it DOES saponify (unlike the waxes), so it stays in the lye math.
Calculate lye for Stearic acid (palm-based)
The calculator below is pre-loaded with Stearic acid (palm-based). 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.
- SoapCalc oil list — SAP, iodine
- From Nature With Love — Saponification Chart — SAP range
- Artiz Soap — SAP Value Table — SAP cross-check
SAP data last updated · 51 oils covered.
Stearic acid (palm-based) soap FAQ
- Can you make soap with 100% Stearic acid (palm-based)?
- It is not recommended. Stearic acid (palm-based) shows its best in a blend, usually up to about 5% 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 Stearic acid (palm-based)?
- A 5% superfat is a safe, common starting point for recipes using Stearic acid (palm-based); 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 Stearic acid (palm-based) speed up or slow down trace?
- Because it is rich in palmitic and stearic acids, Stearic acid (palm-based) tends to bring a batch to trace quickly and set up fast, so work briskly and keep fragrances that accelerate trace in mind. The upside is a firm bar that usually unmoulds within a day or two.