Pure Olive Castile
100% olive oil. Centuries-old recipe. Long cure (6+ months), gentle, low-lather, near-mythical mildness.
True Castile soap dates to medieval Spain — pure olive oil saponified with lye. The trade-off for its legendary mildness is that fresh bars are soft, slow-tracing, and the lather is creamy rather than bubbly. Cure for at least 6 months for a hard, long-lasting bar. Many makers cure 9–12 months for the best texture. Don't rush this one.
Ingredients (1 kg batch)
| Ingredient | Amount |
|---|---|
Olive oil Olea Europaea (Olive) Fruit Oil | 1000.0 g (100%) |
NaOH (lye) | 128.6 g (99% purity) |
Distilled water | 380.0 g |
Open the recipe in the calculator to scale up or down by gram, ounce, kg, or pound.
Expected qualities
Step-by-step
- Soap at lower temperatures (32–38°C / 90–100°F). Olive can take a long time to trace at higher temps but also has a tendency to volcano if overheated.
- Mix the lye-water and let it cool fully — patience is the whole game with Castile.
- Combine and stick-blend. Trace will be slow — 10–30 minutes is normal.
- Pour at light-to-medium trace into a lined mould.
- DO NOT insulate aggressively. Castile is prone to overheat and crack.
- Unmould carefully after 48–72 hours; the bar will still feel soft.
- Cut into thicker bars (more surface area = faster cure) and cure 6+ months.
Notes & troubleshooting
- Bars feel slimy in the first months — that's normal Castile behaviour, will go away with cure.
- If you want a similar feel with a faster cure, see the Bastille recipe.
- Use unflavoured olive oil pomace if your budget is tight; quality is similar for soap.
Calculator-flagged recipe notes
- Hardness score 17 is below the 29 range — bar may be soft.
Regulatory disclaimer
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