How to make soap at home

The method of making soap with lard and caustic soda;

Put 20g of lard, 7g of sodium hydroxide and 50ml of water into a beaker and heat it with an alcohol lamp. While heating, keep stirring to allow lard and sodium hydroxide to fully react. Because of the slow reaction, this reaction time is long. During the reaction, water should be added several times to make up for the water lost due to evaporation.

When you see that the surface of the reaction mixture is no longer covered with a layer of melted crude oil (that is, useless lard), it means that lard and sodium hydroxide have basically reacted completely and can stop heating. Then, 50 ml of hot saturated salt solution was added to the beaker while it was hot, stirred thoroughly, and then allowed to cool to precipitate sodium stearate from the mixture.

Finally, the sodium stearate solid floating on the upper layer of the solution is taken out, and the solution (containing glycerol, salt and unreacted sodium hydroxide) adsorbed on the surface of the solid is washed with water, then dried and molded into soap.

There are three keys to doing this experiment well:

1. The reaction time of lard and sodium hydroxide must be enough, and the heating can not be stopped until the floating grease is not seen on the surface of the mixture. If the reaction is not complete, the soap will contain excessive oil wax and sodium hydroxide, so the decontamination ability of the soap will be reduced and the alkalinity will be stronger.

2. Don't forget to replenish water during the reaction. Always keep about 50 ml of water in the mixture.

3. After the reaction, the volume of the mixture should be kept close to that before the reaction. After the precipitation of sodium stearate, there is still a certain amount of water in the mixture, so that glycerol, sodium chloride and unreacted sodium hydroxide remain in the water. If there is too little water, these three substances will be mixed into soap, affecting its quality.