Glycerin is a natural polyalcohol (trivalent aliphatic alcohol), present in fats because it is the base (tri-glycerides), of the brute formula C3H8O3, also used in the preparation of soaps (its esters, carboxylic groups that replace the hydrogen of the oxyhydrogen group [-OH]) and moisturizing creams for its remarkable hygroscopic properties, ie for its ability to readily absorb moisture from the air.
Glycerin can also be used to extend the shelf life of fruit preserves, as well as that of scientific samples in biology laboratories. Also useful for lubricating molds, making cakes and candles, making printing inks and preventing hydraulic jacks from freezing, glycerin can be extracted from vegetable oil, although it is most commonly made from animal fat. Read the tutorial and learn how to make your own glycerin.
Steps
Step 1. Prepare the animal fat so that it can be dissolved
You can use any variety of animal fat, although beef is commonly preferred. Remove the skin, muscles, ligaments, pulp and tendons for pure animal fat, commonly known as tallow.
Step 2. Melt the tallow
Cut it into small pieces and transfer it to a saucepan, melt it using a low heat. Stir as needed.
Step 3. Prepare the caustic soda solution
Slowly and gradually, pour the caustic soda into the water. The process will generate a lot of heat, so handle the container carefully. Mix the solution gently.
Step 4. Cool the tallow
When it is completely melted, remove the tallow from the heat and mix.
Step 5. Make sure all ingredients are ready to combine
To mix properly, the tallow and caustic soda solution must both be at a temperature of 35 ° C.
Step 6. Combine the ingredients
Slowly, pour the caustic soda solution into the tallow, and mix vigorously.
Step 7. Add the salt
Pour the salt into the mixture and keep stirring. Continue adding the salt until the thick syrup divides into a liquid part, at the bottom, and a gaseous part. At this point, stop mixing.
Step 8. Remove the syrup
When the mixture has cooled to a consistency that can be removed from the pot with a large slotted spoon, do it! What will remain at the bottom of the pot will be a liquid containing salt and some impurities. That liquid is glycerin.
Decide how to use the syrup - hard soap. You can choose to reheat it and then pour it into small molds to make soap bars, or throw it away (however you want because it's not dangerous)
Step 9. Filter the glycerin
When it has cooled, pour the glycerin through a very fine sieve to filter out most of the impurities. This step will not remove all of the dissolved salt. In order to remove the diluted salt it is necessary to distil the glycerin.
Advice
Dissolving tallow will cause unpleasant odors. Do this in a well-ventilated area
Warnings
- Soda is caustic, especially for the soft membranes of the mouth and tongue. Handle it with extreme caution.
- When water and caustic soda are mixed, the heat generated exceeds 93 ° C. Use only tempered glass containers for the caustic solution.
