Making soap – The traditional way

Soap was made traditionally by hand using a source of fat, such as animal lard or used oil, and sodium hydroxide. Nowadays this process is no longer followed, as soap can be easily found in the supermarket. However, this kind of traditions should not be lost, and the only way of keeping them is by teaching the younger generations.

The process of making soap was usually led by women, and were women as well the ones who had to use that soap to wash clothes in the river or in lavoirs. In villages of the countryside, lavoirs were the place were women could meet and gossip while washing the clothes. It was a hard labor, kneeling for long periods of time rubbing the clothes. These were then laid under the sun to air them and make the whites brighter through the action of the sun. Finally, the clothes were again washed and sun-dried.

This hand-made soap was not only used to wash clothes but for basically everything else that required soap: dishes, body, hair.

We made the soap with pig lard, which is a product obtained from the slaughter. In the Spanish countryside, every November a pig reared at home was slaughtered to store meat for the rest of the year. Every single part of the animal was used, even the fat, to make soap, soup, enriched breads, etc.

Although I don’t support the current consumption of meat in our society, in the past, it was difficult to cultivate vegetables during winter, so cured pig meat was the food that could last during the cold months. Furthermore, pigs were part of a sustainable cycle, unlike todays’ industrial production of meat. But this is part of another debate, and we are now in the making process of soap, so let’s start!

What is soap? – The chemistry behind it

The chemical reaction that transforms fats and oils into soap is called saponification.

Fats and oils are contain fatty acids, which are molecules formed by a long hydrocarbon chain. Fatty acids can react with glycerine to form triglycerides, which are found in fats and oils of animal or plant origin. When triglycerides in fat or oil react with NaOH, they are converted into soap and glycerol.¹

What you will need

To make soap you only need 3 ingredients: water, fat and sodium hydroxide. The quantities that I give here are the ones that have been traditionally used, adapted to the dimensions of the soap cast. These make around 20-25 soap cubes. You can also reduce the quantities and adapt it to your needs (e.g. 3.5 L of water, 3 kg of fat, 500 g of NaOH). To make soap you only need 3 ingredients.

• Water (7 L) You can also infuse the water with some herbs to add fragrance to the soap.

 

• Fat (6 kg)

 

• Sodium hydroxide (NaOH) (1 kg). You can also infuse the water with some herbs to add fragrance to the soap.

The materials you will need are: a bucket, a stick to mix, a pot to melt the fat, a cast and a piece of plastic to cover the cast.

VERY IMPORTANT: Sodium hydroxide (NaOH) is a very strong base and it is corrosive, so it can cause skin burns and damage to the eyes and membranes. Therefore, it is highly recommended that you wear protective equipment, such as GLOVES, GOGGLES, LONG SLEEVES AND MASK. In the pictures that I show here you might see bare hands, but these people have been making soap for almost all their life, so they have experience and know the risks of using NaOH and also know how to adequately work with it. Please FOLLOW THE INSTRUCTIONS THAT I GIVE BELOW regarding the use of NaOH and carefully adding it to the fat, to avoid overflowing and splashes that can burn your skin. However, I am not responsible for any misuse of the instructions and accidents that could happen during the soap-making process.

The making process

Prepare the water and lard

1. If you decide to add herb-infused water, bring 7 L of water to boil and add the desired herbs. Let it rest for around 2 hours.

2. Add the lard and the water (either infused or not infused) into a pot and heat up until the lard melts.

3. Once all is melted, pour the lard-water mixture into a bucket.

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Adding the Sodium Hydroxide

1. Start adding the NaOH LITTLE BY LITTLE. It is VERY IMPORANT that you add the NaOH a bit at a time, because the fat-NaOH reaction is exothermic, meaning that the mix will increase the temperature and start to boil. This can make the mix to bubble up and splash out, causing severe burnings to the skin due to the high temperature and the corrosiveness of NaOH.

1. • Add a bit of NaOH, wait a few seconds and add a bit more. Stop and wait for longer if you see that the mix is bubbling up harder and is risking to overflow the container.

2. Once you have added all the NaOH, let it rest for about 3 minutes.

3. Start stirring with a stick, ALWAYS TOWARDS THE SAME SIDE. Don’t change the stirring direction.

4. After about 20 minutes stirring, the mixture should turn into a lighter color and change consistency (as seen in the picture). If the mixture is curdled and looks separated, add some more hot water and keep stirring until the consistency changes.

5. Pour the soap into the plastic-lined cast and use a spatula to level the surface. Leave the soap firm up for 24 hours (not longer otherwise it will be difficult to cut), afterwards remove from the cast and cut with a knife to the desired size.

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Curing of the soap

1. The soap now has to rest (cure) for at least 4 weeks. Keep it in a ventilated place, away from direct light, and over a stone or baking paper, to protect the surface were you leave the soap. During this time, the saponification process will be completed, reacting all the possible remaining NaOH (sodium hydroxide). The pH will decrease, making it non-harmful for the skin and the water will evaporate, hardening the soap. The color will probably change too.

2. After the curing time the soap will be ready to use. You can now use it to wash your clothes (either by hand or in the washing machine if you grate the soap) and your hands.

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RESOURCES

1. OLABS. Retrieved from: http://amrita.olabs.edu.in/?sub=73&brch=3&sim=119&cnt=1