Duck Fat has a saponification (SAP) value of 0.138 for NaOH (bar soap) and 0.194 for KOH (liquid soap). It's typically used at 5-35% of the oils.
How much lye for Duck Fat?
Lye at 0% superfat = oil weight × SAP. Apply your superfat to reduce it (e.g. ×0.95 for 5%).
| Duck Fat | NaOH (0% SF) | NaOH (5% SF) | KOH (0% SF) |
|---|---|---|---|
| 100 g | 13.8 g | 13.1 g | 19.4 g |
| 250 g | 34.5 g | 32.8 g | 48.5 g |
| 500 g | 69 g | 65.6 g | 97 g |
What Duck Fat does in soap
| Property | Value |
|---|---|
| Hardness | 32 |
| Cleansing | 0 |
| Conditioning | 60 |
| Bubbly lather | 0 |
| Creamy lather | 32 |
| Longevity | 32 |
Values are the oil's solo contribution (SoapCalc-style property model). Real bars blend several oils — build the full recipe to see the combined profile.
Fatty-acid profile
| Fatty acid | % |
|---|---|
| palmitic | 24% |
| stearic | 8% |
| oleic | 45% |
| linoleic | 14% |
| linolenic | 1% |
Build a recipe with Duck Fat in SoapCalc — it computes the exact lye for your oils at any superfat and saves the recipe. See all soap-making oils or the SAP value chart.