Formula · Coconut-led
Coconut Laundry Bar, Zero Superfat
The one bar in this library that is not for skin. Coconut oil alone, no superfat at all, cured three weeks and used with gloves on stains and work clothes.
RRecipe card
| Oil | Share | SAP |
|---|---|---|
| Coconut Oil (76 °F) | 1 % | 0.183 |
| Oil bill | 1 % | 183 |
| NaOH to weigh | 184.8 g | NaOH @ 99 % |
|---|---|---|
| Water to weigh | 300 g | 1.64 : 1 |
| Superfat | 0 % | Lye concentration 37.9 % |
| Yield | 10 × 148.5 g | Cure 3 weeks |
Reference bands follow the usual cold-process targets; the marker turns orange when a figure sits outside its band.
TTechnique notes
Why zero superfat
Superfat is unsaponified oil left in the bar. On skin that is a good thing. In laundry it is exactly what you do not want: leftover oil redeposits on fabric, holds dirt, and turns white shirts grey over a few months.
So this bar runs at 0 % — every gram of oil is converted. The consequence is that the bar has no buffer against a weighing mistake. If you are 2 g light on the lye, you have made a bar with 0.2 % superfat and it will be fine; if you are 2 g heavy, you have a bar with a caustic excess. Weigh twice.
What the profile actually looks like
Hardness 80, cleansing 67, bubbly 67, conditioning 10. Against bands of 29–54, 12–22, 14–46 and 44–69, every single marker is outside its range — three above, one far below. This is the most extreme profile on the site.
That is the point. The high lauric and myristic content that makes this bar harsh on skin is the same thing that makes it a good detergent: it dissolves quickly in cool water, lifts oil well, and rinses clean because there is nothing left to redeposit.
Using it
For a stain: wet the fabric with cold water, rub the bar directly on the mark, work it in with a stiff brush, leave ten minutes, then wash as normal. Warm water sets protein stains, so cold first is not optional.
For a full load: grate 30 g of the bar into 1 L of hot water, stir until dissolved, let it cool to a gel, and use 100 ml per load. It has no fragrance, no optical brightener and no enzymes — if your clothes are heavily soiled, that matters.
Add at trace
- None. Anything added to this bar is something that will end up on the clothes
Equipment
- Digital scale to 0.1 g — at 0 % superfat the charge has no slack in it
- Stick blender
- A mould you do not mind dedicating to laundry soap
- Rubber gloves for using the finished bar
When it goes wrong
- The batch got hot enough to volcano out of the jug
- 100 % coconut with no superfat is the fastest, hottest reaction in this library. Mix at 35 °C, use a jug twice the volume you need, and never blend continuously.
- The finished bar feels harsh and cracks the skin on your hands
- It will — it is laundry soap with no superfat, cleansing score in the high sixties. Wear gloves, and do not hand this to anyone as a bath bar.
MMix
- Weigh 1000 g coconut oil. It is solid below 24 °C; warm it to 35 °C so it is liquid but not hot.
- Weigh 300 g water. With goggles and gloves, add 183 g of NaOH. This is a hot solution — coconut oil saponifies fast and 100 % coconut with no superfat runs hotter than anything else in this library.
- Let the lye cool to 35 °C and let the oil sit at 35 °C. They should be within two degrees of each other.
- Pour the lye in and blend in 3-second bursts. This will reach medium trace in under a minute. Stop before it thickens past pourable.
- Pour into the mould immediately and tap it down. There is no fragrance to add and no time to add it.
CCut
- Unmould at 12–18 hours. A 100 % coconut bar is hard fast — it will be firm enough to knock out of a silicone mould the next morning.
- Cut at 24 hours. Cut thick: 2.5–3 cm slices, about 100 g each. Thinner slices of this bar snap in half under a washboard.
- Wear gloves to handle the fresh bars. At 0 % superfat the surface stays alkaline longer than a normal bar.
CCure
- Three weeks is enough for a laundry bar — it is not going on skin, so the lather quality matters less than the hardness.
- Store the cured bars unwrapped in a dry cupboard. This bar absorbs moisture from the air and a wrapped one will go soft at the surface.
- Use it on stains with cold water and a stiff brush. Grate 30 g into a litre of hot water for a liquid laundry soap; it gels as it cools, which is normal.
What matters here
- 0 % superfat: every gram of oil is saponified, so nothing redeposits on fabric.
- Profile: hardness 80, cleansing 67, conditioning 10. All four markers outside band, deliberately.
- Mix at 35 °C in a jug twice the volume you need, and never blend continuously.
- Cut thick — 2.5–3 cm. Thin slices snap.
- Gloves for the finished bar. This is not a bath soap.
Questions that come up
- Can I use it on my hands?
- You can, and a lot of people do for heavy grease. It will strip your hands badly. If you want a hard-working but usable hand bar, drop the superfat to 2 % and add 10 % olive oil.
- Why is my bar white and brittle?
- 100 % coconut with no superfat is a hard, dense, slightly brittle bar — it is normal for a corner to chip when you drop it. If it crumbles when cutting, you cut too early; give it another 12 hours.
- Does it work in a front-loading machine?
- The grated version does, at about 100 ml of gel per load in soft water and 130 ml in hard water. Do not put a whole bar in the drum; it will not dissolve and can damage the seal.
Next on the bench
Cold-process soap is made with sodium hydroxide: goggles, gloves and ventilation. This bar has no superfat and stays alkaline on the surface longer than a bath bar — wear gloves when you use it, and keep it away from children and animals.