Why coconut oil is everywhere in soap recipes
Open a collection of handmade soap recipes and coconut oil appears in the majority of them. There is a good reason. Coconut oil is one of the few widely available fats that makes a bar both hard and very bubbly, and those are two qualities most people want in soap.
Coconut oil is high in saturated fatty acids, in particular lauric acid, along with myristic acid. When these react with lye, they form soaps that dissolve readily in water and produce abundant, fluffy foam. That chemistry explains why coconut-heavy bars feel strongly cleansing.
What it adds to a bar
Hardness. Coconut oil is solid at cooler room temperatures, and soap made from it is firm. Adding it to a recipe built on soft oils like olive helps a bar release from the mold cleanly and hold its shape in use.
Big, quick lather. The bubbles come fast and are large and airy. Many people associate this with a clean feeling. Lather that appears quickly but fades quickly is typical, which is why makers often combine coconut oil with a lather stabilizer such as castor oil.
Cleansing power. Coconut-based soap is effective at removing oils. That is useful for some purposes, such as hand washing or a kitchen bar, but it brings a drawback covered below.
Mild scent and wide availability. The soap carries only a faint scent, and refined and unrefined versions are widely available and generally affordable, though prices vary.
Why recipes often limit it
Because coconut-based soap is so cleansing, a bar made with a lot of it can feel stripping. On some skin, particularly dry or sensitive skin, a bar with a very high coconut share may leave a tight, dry feeling after washing. This is not the case for everybody, and people differ in how they respond, but it is the main reason many recipes cap the amount.
Common practice is to keep coconut oil to a limited share of the total oils. The exact figure varies. Recipes for oily-skin or utility bars may use more; recipes intended for gentle facial or sensitive-skin use may use less. Rather than quoting a number here, the sensible habit is to use a tested recipe from a reliable source and to treat a very high coconut share as something to approach cautiously.
Some other considerations favor moderation.
- Superfat. Makers often use a higher superfat level in a high-coconut bar to compensate for the cleansing effect, leaving more unreacted oil in the bar for a gentler feel. The topic of soap superfatting covers what that means.
- Brittleness. A very hard coconut bar can crack or be brittle, particularly when cut.
- Cost and sourcing. Like other tropical oils, coconut is shipped long distances, and some makers consider the environmental footprint.
Coconut oil and the rest of a blend
Coconut oil does its best work as a team member. A typical balanced recipe uses it for hardness and bubbles, a soft oil such as olive for conditioning, a butter for creaminess and perhaps a little castor oil to extend the lather. Each partner offsets a weakness of the others. Where a maker wants to avoid palm, coconut often takes on a bigger role, which is one reason the palm free soap conversation keeps returning to it.
Types of coconut oil
- Refined (RBD) coconut oil is deodorized and usually has little scent.
- Virgin or unrefined coconut oil keeps more of the natural coconut aroma, although much of that fades in the finished bar.
- Fractionated coconut oil stays liquid and is mostly not used in cold process soap, because it has had the lauric acid component removed. It behaves very differently.
Check which type your recipe calls for, and recalculate with a soap calculator if you change to a different oil, since lye requirements differ.
Handling in the batch
Coconut oil is solid in cool rooms, so it usually needs gentle melting before use. Soaps high in coconut oil tend to reach trace fairly quickly and may be firm enough to cut earlier than softer bars. Always weigh the oils, and keep the usual lye precautions in mind: wear protective gear, ventilate the workspace, and keep children and pets well away.
Who might want a different approach
Anyone with persistently dry, itchy or reactive skin may prefer a bar with a lower coconut share, or a different type of soap altogether, and may find the guidance on eczema prone skin and soap choices relevant. Allergy to coconut is uncommon but possible. A small patch test is wise, and persistent skin problems are best discussed with a health professional.