How to Make Liquid Soap in Kenya: Formulation, Costing and Common Mistakes

This is the formulation we hand over the counter to people starting out. It makes about 20 litres, costs a little over three thousand shillings in materials at current prices, and produces a soap that stands comparison with what is on the shelf.

What you need for 20 litres

The method

1. Soften the water first

Most of Nairobi, Kiambu, Machakos and the Rift is on hard water, and borehole supply is harder still. Calcium and magnesium tie up your surfactant, which is why a recipe that foams beautifully in a video foams poorly in a Kariobangi workshop. Dissolve the EDTA or STPP in the water before anything else goes in.

2. Neutralise the LABSA properly

Dissolve the caustic soda in cold water in its own bucket, never the other way round, and let it cool, the solution gets genuinely hot. Add the LABSA to the drum, then trickle the caustic solution in while stirring. Check with pH paper and stop between 7 and 8. Too low and the product stings; too high and it will irritate skin and eat at your packaging.

3. Add the SLES slowly

SLES 70 is a thick paste. Warm it slightly if it is stiff, and stir it in gently. Whipping air into the batch at this stage is the single most common cause of a product that looks like a milkshake for two days.

4. CDEA, then the finishing materials

The CDEA gives the foam its density and adds body. After it is uniform, add preservative, then colour, then fragrance. Fragrance last, because it is the most volatile and the most expensive thing in the drum.

5. Thicken with brine, carefully

Never throw dry salt into the batch, it sits at the bottom and you overdo it. Make a brine and add it a little at a time. Viscosity climbs, peaks, then falls, and once you are past the peak there is no coming back. Stop a shade thinner than you want, because it will firm up overnight.

6. Rest it

Leave the drum covered overnight. Air comes out, the colour evens, and you can check the pH once more before packing.

What it costs

At current published prices the chemicals for a 20 litre batch come to roughly three thousand shillings, which is about 150 shillings a litre. Then add your packaging: four 5 litre jerry cans and caps, or twenty 1 litre bottles with labels. Packaging is usually a third of the total cost, and it is what new producers forget when they set a price. See the packaging page for those figures.

Where it usually goes wrong

It came out thin and will not thicken. Too much salt, or not enough CDEA. If you are past the salt peak, the fix is to blend in a fresh batch made without salt.

It separates after a week. Usually poor mixing of the CDEA, or fragrance added to a batch that was too warm.

It smells sour after a month. No preservative, or not enough. Water-based products in a warm store will grow something.

It stings hands. pH too high. Check with paper, not by eye.

Scaling up

The recipe scales linearly. At 200 litres a month you should stop buying 5 kg pails and move to 25 kg, which is where the margin improves noticeably. At a tonne, drums make sense if you have somewhere safe and cool to keep them.