If you have already started making biodiesel you will know that the main by-product is glycerine. What you may not know is that you can turn this “waste” into a product you can use – or even sell to pay for your raw materials.
The product in question is soap. Most soap is glycerine based, cheap and easy to buy anywhere at a relatively low price. However “home-made” and “natural” or “homeopathic” soaps are much sought after product – and these are exactly the kinds of product that you can make at home with your left over glycerine.
Don’t believe me? Feel free to Google Home Made Soap, or search on Ebay – home made soap sells for up to $8 a bar!
There are two types of soap you can make – liquid and solid. I’ll cover liquid soap here, there’s a recipe for making solid bars in the new edition of this guide.
Making Liquid Soap from Glycerin
Liquid soap is particularly good for cleaning greasy hands or equipment and you can put it into any pump dispenser.
Step 1 – Remove any residual alcohol.
Your glycerine will contain almost 100% of the catalyst you used for you biodiesel reaction. As such, the glycerine and KOH (or lye) will have already formed soap by the time you drain it from your biodiesel reaction chamber.
There will be some unreacted alcohol left in your glycerine, which you will need to remove otherwise you will end up (at best) with a very harsh soap. To do this you need to heat your glycerine past the boiling point of the type of alcohol you used, which will cause the alcohol to evaporate off, leaving just the glycerine soap, for you to enhance into a great end product.
N.B. Make sure that you get the temperatures right; methanol will need to reach 148 degrees F (65 degrees C). Ethanol will need to reach 175 degrees F (79 degrees C). Allow the glycerine to stay heated for at least 10 minutes and then allow the glycerine to cool.
Step 2 – Enhancing your Soap
You can add essential oils and fragrances to your soap to enhance its aroma. Popular fragrances include:
Oats (for exfoliation in solid soaps only)
I particularly like the last three as you can grow them for free in your garden!
You will need to add about 150-200 millilitres of manufactured fragrance oil or 50 millilitres of essential oil per litre of glycerine; alternatively, you can add up to 300 grams of dried herbs/flowers. You can also enhance the color of your soap by simply adding food coloring.
Step 3 – Cooking it All Up
Take your alcohol free glycerine and heat it in a suitable container until it liquefies. Then simply pour in the fragrance oil and or the dried flowers/herbs. Stir lightly as you add the ingredients to ensure that they are evenly distributed.
Last but by no means least pour your liquid soap into a suitable container, a sturdy plastic tub or old pump soap dispenser and leave it to cool. Leave the lid off for about a week and the end result should be a fantastic, aromatic liquid soap.
- Always make your biodiesel and soap in a well ventilated area.
- Always use an open container to encourage the circulation of air.
- Don’t breathe the fumes.
- Always use oven gloves and if possible goggles or glasses when handling hot liquids.
If you are going to make biodiesel then why not turn this waste by-product into a useful, cash generating product? Also remember that like anything practice makes perfect, so don’t be afraid to experiment! Once you’ve made your soap you might want to consider purchasing some simple, cheap containers and labels and packaging the soap up for sale on Ebay, your own website or at your local car boot sale. Enjoy