Zero-superfat coconut laundry bar
A hard, plain laundry bar of coconut oil with the superfat taken out, so no free oil goes into the wash. Rub it on stains, or grate it with washing soda into a laundry powder. Unscented, and not for skin.
- Skill
- Beginner
- Method
- Cold process
- Batch
- 1000 g of oils about 1522 g of batter
- Hands-on
- 45 min
- Cure
- 4 weeks
- Gel phase
- Either way gel or not, both work
What you need
For 1000 g of oils, which fills a 1.5 litre loaf mould. Weigh everything, liquids included.
| Coconut Oil · 100.0 % | 1000 g | 35.27 oz |
| Sodium hydroxide (NaOH) · the lye, 100 % pure | 182.9 g | 6.45 oz |
| Distilled water · for a 35 % lye solution | 339.6 g | 11.98 oz |
| Washing soda (sodium carbonate) · for the laundry powder, mixed with one grated cured bar; not part of the soap | 1 cup |
- Superfat
- 0 %
- Temperatures
- Oil and lye solution at 32 to 38 °C (90 to 100 °F), left uncovered
Method
-
Get ready
Put on goggles, gloves and long sleeves, open a window and line a 1.5 litre loaf mould. Weigh 1000 g coconut oil into the pot, 339.6 g distilled water into the lye jug and 182.9 g sodium hydroxide into a small dry container. -
Make the lye solution
Pour the sodium hydroxide into the water, never the water onto the lye, and stir until it runs clear, keeping your face away from the vapour. Let it cool to 32 to 38 °C (90 to 100 °F). -
Melt the coconut oil
Warm the coconut oil until it is just clear, then let it cool to the same 32 to 38 °C (90 to 100 °F). Don't let it get much cooler: coconut oil starts to set again below about 24 °C (75 °F). -
Blend to light trace
Pour the lye solution into the oil and stick blend in short pulses. Coconut oil traces quickly, so stop at light trace, when a drizzle leaves a faint line on the surface. -
Pour and leave it uncovered
Pour into the mould and tap it on the worktop to let air out. Leave it uncovered in a cool room with no towel over it: coconut soap makes plenty of heat of its own and can crack if it is kept warm. -
Cut it the same day
Coconut soap sets hard quickly. With your gloves on, unmould and cut it as soon as it holds a clean edge, often 4 to 12 hours after pouring; left too long, it cuts with chips and cracks. -
Label it and keep it apart
Handle the fresh bars with gloves, label them as laundry soap and store them away from your bathroom soap, so no one takes them for hand soap. -
Cure for four to six weeks
Stand the bars on a rack with air around them for four to six weeks. A dry bar lasts longer and grates to a finer powder. -
Grate a bar
Grate one cured bar on the finest holes of a grater, somewhere the dust will not blow about. -
Mix the laundry powder
Stir the grated soap into 1 cup of washing soda (sodium carbonate) in a lidded jar, and label it. Washing soda causes serious eye irritation, so wear gloves and goggles while you mix and keep the jar out of children's reach. -
Dose it
Start with 2 tablespoons for a front-loading machine and up to half a cup in a top-loader, dissolved first in a cup or two of hot water, and adjust for your water and your load. A homemade powder has no HE rating, so check your machine's manual before using it in a high-efficiency washer. -
Use a bar on stains
Keep a bar by the sink: wet the stain, rub the bar into it, leave it for a while, then wash as usual.
Tips
- At 0 % the calculator's range check puts this bar anywhere from about 3 % oil-rich to about 3 % lye-heavy, depending on where your coconut oil sits in its published range. In a wash that washing soda has already made strongly alkaline that makes little difference; on skin it does, which is why this is not a hand soap.
- Soda crystals, as sold in the UK, are hydrated sodium carbonate, and only 37 % of their weight is carbonate. It takes about 2.7 times the weight of crystals to do the work of washing soda.
- Soap and soda make a strongly alkaline wash. Wash wool and silk in a mild, neutral detergent instead, and in hard water expect to need more powder, since some of the soap goes to scum.
- Borax is left out on purpose. The EU classifies it as toxic for reproduction and restricts its sale to the public, and the soap and washing soda do the cleaning without it.
The oils
| Oil | Share |
|---|---|
| Coconut Oil | 100.0 % |
How it is made
| Process | Cold process |
| Alkali | NaOH |
| Superfat | 0 % |
| Water | lye water at 35 % |
| Iodine value | 8 |
| INS | 248 |
Why make it
Soap did the laundry long before synthetic detergents, and a coconut bar with no superfat is the traditional choice. Coconut oil gives the most cleansing soap there is, 68 on our scale, and its soap dissolves even in salt water, which is why marine soap was made from it (Simmons and Appleton); with no superfat there is no free oil to mark the wash. Makers use it grated with washing soda as a cheap, fragrance-free powder, as Letcavage and Harden do, or rub it straight onto stains. The limits are real: in hard water part of any soap turns to scum (USGS), so whites can grey over time, and a homemade powder carries no rating for high-efficiency machines. It is not for skin.
Sources
- The Handbook of Soap Manufacture · Scott, Greenwood & Son, 1908
- Natural Soap Making · Stackpole Books, 2013
- Hardness of water · U.S. Geological Survey
What tradition, makers' experience and research say about soaps like this, each labelled for what it is. It is not medical advice, and no soap treats a skin condition: if you have one, ask a doctor or pharmacist.
What the numbers say
- Lauric acid 49.2 %
- Myristic acid 18.9 %
- Palmitic acid 8.9 %
- Stearic acid 3.0 %
- Oleic acid 7.5 %
- Linoleic acid 1.8 %
- Other 14.3 %
Saturated : unsaturated 91 : 9
Computed from the fatty acids of the fats above. The bands are what the craft has settled on, not chemistry — a bar outside one is not wrong.
From the guides
All guides
Laundry soap bars and household soap
Why laundry and kitchen bars are high in coconut and made with almost no superfat, how to grate one into laundry powder, and what washing soda and borax do.
Superfat and lye discount: why recipes leave some oil unsaponified
What superfat and lye discount mean, how the calculator applies them, where makers set them for each soap, and why oil added at trace isn't the oil left over.
Soap in hard water: scum, chelators and rinse
Why soap turns to scum in hard water, how much soap each litre wastes, what a chelator in the bar can and cannot do, and why coconut soap copes best.
Guides with this recipe
Where these proportions come from
Craft convention fixes this one: a laundry bar is a high-lauric soap made with no superfat, because free oil is the one thing a wash should not leave behind, and coconut oil on its own makes the most cleansing bar there is. The laundry powder follows Letcavage and Harden's grated-bar method with the borax left out, as our laundry soap guide explains.
Formulation adapted from Natural Soap Making by Elizabeth Letcavage and Melissa Harden (Stackpole Books, 2013). The method and notes are ours.