Biodiesel Recipe.

Before reading the Recipe on how to make your own Biodiesel please read our Terms & Conditions.

The Information contained on this website and the biodiesel recipe is for informational purposes only and we do not recommend that you actually make biodiesel at home due to the dangerous nature of the chemicals used in the process.

If you still want to make your own Biodiesel extreme caution should be taken when handling the chemicals.

When handling the chemicals it is advisable to always wear protective gloves, a protective apron, safety goggles and a mask so that you don't inhale any vapours. Methanol is extremely toxic and 100-125ml (4 fl. oz.) is enough to kill a grown man. Always wear gloves when you handle Methanol as it can also be absorbed through your skin. If Methanol is ingested seek medical attention immediately. One of the symptoms of Methanol poisoning is permanent blindness. The other chemical, Sodium Hydroxide can cause severe burns and be fatal if ingested. Together methanol and sodium hydroxide form sodium methoxide which is an extremely caustic chemical. Work in a well ventilated area and always have running water nearby. The safety instructions on the chemical products must always be adhered to. Handle these chemicals with care.

Do not worry about the Biodiesel Equipment and Processors that will come later. This section is about the Recipe for making Biodiesel. First get this right on a small scale and then when you are comfortable and getting High-Quality Biodiesel consistently, go to Biodiesel Processors and start doing it on a bigger scale.

Recipe for making your own Biodiesel.

Ingredients.

Biodiesel Mixture.

• Used/waste vegetable oil (WVO). If this is your first time making Biodiesel make a small 1 litre batch first by using fresh unused vegetable oil.
• Methanol (CH₃OH). It must be pure methanol - 99%+. It is also possible to use ethanol (which you can also make yourself) to make biodiesel but this is a bit more difficult than using methanol.
• Sodium Hydroxide (NaOH) also known as lye or caustic soda - must be dry.

Titration.

• Isopropyl alcohol also known as rubbing alcohol - 99%+ pure.
• Distilled water.
• Phenolphthalein solution. This is used to indicate the pH of something. It is not the same as Phenol red that you use to test the pH of your pool. Make sure it is Phenolphthalein, specifically 1% Phenolphthalein solution with 95% ethanol. Phenolphthalein has a shelf life of about a year, don't use anything older.

Biodiesel Washing.

• Water
• Vinegar

Procedure.

1. Safety.
2. Preparing the Feedstock.
3. Titration.
4. Preparing the Sodium Methoxide.
5. Mixing.
6. Settling.
7. Washing & Drying.
8. Quality Test.
   

Safety.

Extra care should be taken when working with dangerous chemicals. Always wear protective gloves, safety goggles and wear protective clothing like an apron or overall. When working with chemicals with strong fumes you should work in a well ventilated area. Never has someone been killed while trying to make Biodiesel at their home, but these are dangerous chemicals and even a small dose of it is enough to be fatal. Please take all the necessary precautions to ensure your own safety and the safety of those around you.

Preparing the Feedstock.

If you are using fresh unused vegetable oil it is not necessary to do any preperation work as there should not be any water or foreign matter in the oil.

When using Waste Vegetable Oil (WVO) as feedstock you will need to filter it and boil of any excess water.

To filter the WVO heat it up to about 35°C (95°F) to get it flowing more freely. Use a cheesecloth or a paper filter like the ones they use in coffee machines and a funnel to get rid of all the food particles that may be in the oil.

Be careful to avoid burning when working with hot oil.

Waste Vegetable Oil will probably contain some water which you will have to boil off. Water in your biodiesel feedstock will slow the reaction and cause saponification (soap formation). To get rid of the excess water raise the temperature of the oil to 100°C (212°F) and hold it there for a few minutes to allow all the water to boil off. Use a mixer to avoid steam pockets forming below the oil and exploding, splashing the hot oil out of the container. When the boiling slows raise the temperature to 130°C (265°F) and hold it there for a few more minutes. Remove the heat and allow to cool.

This step uses a lot of extra energy, but there are ways to do it more efficiently. Experiment with glycerine burners or use your own biodiesel in a burner or generator if that works out cheaper than using electricity from the grid.

Titration.

This step is critical if you want to make Biodiesel that measure up to global standards.

What is Titration? According to Dictionary.com Titration is:

"The process or operation of determining the concentration of a substance in solution. Titration is performed by adding to a known volume of the solution a standard reagent of known concentration in carefully measured amounts until a reaction of definite and known proportion is completed (as shown by a color change or by electrical measurement) and then calculating the unknown concentration."

To know the amount of Sodium Hydroxide (the unknown concentration) that is required a titration needs to be preformed on the oil that is going to be used to make the Biodiesel.

Sodium Hydroxide (also known as lye, caustic soda or NaOH) must be kept dry in an airtight container. When working with the lye be quick as it will absorb the moisture in the air and interfere with the reaction.

Measure out 1 gram of Sodium Hydroxide and mix that with 1 litre of Distilled water. Make sure that the Sodium Hydroxide dissolves completely. This will be the reference tester for the Titration process. This solution can be used on more than one titration if you don't let it get contaminated.

Next take 10 millilitres of Isopropyl alcohol (rubbing alcohol) in a small container or a test tube. Add to this exactly 1 millilitres of your waste vegetable oil. Take the sample oil after the oil has been heated and stirred.

Add to this solution 2 drops of Phenolphthalein. The phenolphthalein is an acid-base indicator that is colourless in acid and red in base. It has a shelf life of about a year, anything older than a year will not be accurate. Store it in a dark place as light will speed up the degradation.

Use a graduated eyedropper to add measured amounts of the Sodium Hydroxide-Distilled water solution to the WVO-Isopropyl Alcohol-Phenolphthalein solution. Do not add more than one tenth of a millilitre of the first solution to the second solution at a time and keep track of exactly how much you are adding. After each drop stir the solution vigorously. Do this test in a heated room, because cold weather will effect the results of the titration.

Keep adding the solution and stirring until the second solution turns pink, and stays pink for about 10 seconds. This is the indication that the solution has a pH of between 8 and 9. It is important to not add too much of the solution, you should just reach this level.

Repeat the titration a second time to make sure that you have the correct amount. The amount of the Sodium Hydroxide/Distilled water solution needed to get to a pH of 8 to 9 is between 1.5 and 3 millilitres depending on the oil used. It is possible to do this test with litmus paper or with a digital pH meter instead of Phenolphthalein.

To determine how much Sodium Hydroxide is needed to make your biodiesel you should do the following calculation:

Take the amount of the solution used to get to a pH of between 8 and 9 and multiply that with the amount of waste vegetable oil that will be used to make the Biodiesel. Fresh unused vegetable oil needs 3.5 grams of sodium hydroxide for every liter. So for every one litre of WVO you need to add an extra 3.5 grams of sodium hydroxide.

For example. It took 2.5 milliliters of solution to get to the right pH level. You have 100 litres of waste vegetable oil that you want to use to make Biodiesel. So 2.5 x 100 = 250 and because WVO is used add 3.5 x 100 = 350. So 250 + 350 = 600 grams. That means that you will require 600 grams of sodium hydroxide for the 100 litres of WVO.

When making large quantities of biodiesel it might be a good idea to make a small test batch first. When making a small test batch use a kitchen blender to mix up the ingredients. Use a blender that will not be used for food ever again. When you use a blender it is not necessary to heat up the oil that much, the blender spins fast enough to mix all the ingredients together very well. Making 1 litre test batches will allow you to determine the exact amount of catalyst that you require to make your own biodiesel at home.

When you use too much lye you will get a gel that you can make soap with and not much else and when you don't use enough some of the oil is left unreacted and you end up with three layers at the end. A layer glycerine, a layer Biodiesel and a layer unreacted oil. If there is too much water in the WVO there will form a fourth layer on top. This layer is very difficult to separate from the WVO layer and Glycerine layers.

This is the most important step in the whole Biodiesel making Process, so take your time and make sure that you get it right.

Preparing the Sodium Methoxide.

Sodium Methoxide is what you get when you mix Methanol and Sodium Hydroxide. The chemical reaction generates a lot heat. This mixture is very caustic and will burn your skin, killing the nerves, without you even knowing it. Have running water nearby when you are working with sodium methoxide and when it gets on your skin rinse it immediately off. Work in a well ventilated area and don't inhale the vapours.

On average the methanol required is 20% of the mass of the waste vegetable oil. For example for every 1 litre of WVO you will use 200 millilitres of methanol. To be 100% sure take half a litre of both liquids, weigh them both and calculate 20% of the mass. Methanol and WVO have about the same densities, so the methanol will be about 200 millilitres per litre of oil. For example: 500 millilitres of methanol and 500 millilitres WVO's combined weight is 1000 grams. 1000 x 20/100 = 200. That means you need to use 200 millilitre of Methanol for every 1 litre of Waste vegetable oil.

Mix the amount of methanol required with the amount sodium hydroxide required, as calculated in the previous step. Do this in a stainless steel or glass or enamel container if possible. Do not use aluminium, tin or zinc as the lye is very caustic and will react with these materials. Be careful not to inhale the fumes of the Sodium Methoxide.

Mixing.

Heat the WVO to 50°C (122°F). Use a drill or an electric motor to make an improvised mixer. A paint stirrer or a home made propeller on a shaft that will fit in the drill will work fine. You don't want splashing and bubbles. Adjust the speed so that the vortex on the surface is barely visible.

Add the Sodium Methoxide to the heated WVO while stirring. Stir the mixture for an hour. The reaction only takes half an hour but keep stirring for another half an hour to be sure everything is thoroughly mixed.

Settling.

Allow the mixture to settle and cool for at least 8 hours. Let it stand over night just to be sure. There should be only two layers. The Biodiesel will float on top, while the denser glycerine will settle at the bottom. Glycerine solidifies at temperatures below 38°C (100°F). To separate the biodiesel from the glycerine you will have to heat up the mixture again. Heat it up just enough to get the glycerine to flow freely. Do not stir the mixture, if you do you will have to wait for the glycerine to settle at the bottom again. Drain the dark brown coloured glycerine from the bottom of the tank into a container. As soon as the honey coloured biodiesel starts coming out divert it to a different container. If you get a little bit of Biodiesel in the glycerine container, don't worry. Once the glycerine solidified again it will be easy to pour off the biodiesel.

Another way of doing this is to keep the mixture at above 38°C (100°F) after the mixing process. Keep it at this temperature for at least an hour to allow the glycerine and biodiesel to separate. Do not stir the Mixture while it settles or while draining. When the glycerine has settled at the bottom, drain it off the same way as described above.

Keep the Glycerine to be used later.

Go Biodiesel Byproducts to find out more about what you can do with Glycerine.

Washing & Drying.

The Biodiesel at this stage will contain some impurities and before you can use this Biodiesel in an engine it will have to be washed and dried. The impurities, mostly soap, formed due to water in the waste vegetable oil or water absorbed from the atmosphere by the sodium hydroxide. Even if you did boil off all the excess water from your WVO it is still necessary to do this step. There are a few ways of getting your biodiesel ready for your tank.

The first way is the easiest, but also not the best. The easiest way usually isn't. What you have to do is to let the Biodiesel stand for a week to let most of the soap settle and then run it through a series of filters. Try paper filters, cheesecloth or a Micron Filter. By cooling the Biodiesel you can get the soap to settle faster.

Another way is to wash the biodiesel using water and vinegar. You will need a container with a valve about 10cm (4in) from the bottom. Fill the container with water up to halfway between the bottom and the valve. Add a small amount of Vinegar to the biodiesel. This will bring the biodiesel closer to a pH of 7. Then add the biodiesel to the container with the water and stir it gently. Allow it to settle for a day so that the Biodiesel and the water can separate again. Drain the clean Biodiesel and discard the soapy water.

Repeat this process at least two more times. For the second and third wash it is not necessary to add vinegar to the Biodiesel being washed. To save water you can keep the water from the third wash and use it to do the first wash of the next batch.

A third way to get High Quality Biodiesel is to use a process called bubble washing. You will need an air stone or an areator that they use in fish tanks. Add 30 millilitres of vinegar per 100 litres of biodiesel and half of the volume in water. Add this to a container with the areator resting on the bottom and let it bubble away for 12 to 24 hours. What happens is that every bubble that floats through the mixture to the top is covered in a layer of water that washes the biodiesel. At the top the bubble bursts and leaves a drop of water that floats back down and wash the biodiesel a second time. If the Biodiesel is still cloudy after a few hours of washing add a bit more vinegar After 12-24 hours drain off the water and skim off the wax that accumalated on the top.

Repeat this process two more times until you have a clean biodiesel without any cloudiness or residues. You can use the water from the third wash for the first wash of your next batch as well.

Before using this biodiesel you should make sure that there is no water left in it from the washing process. Slowly heating up the Biodiesel will let any water and impurities still left in it sink to the bottom. Or gently heat it up to 50°C (122°F) and let the extra water evaporate.

Quality Test.

The final step in the diy biodiesel recipe is the quality test. Only use high quality biodiesel in your car. There are some people that goes around throwing anything they can get their hands on in their fuel tanks and end up destroying their engines in the process. They then go and blame the catastrophic engine failure on Biodiesel... Those people has given biodiesel a really bad name. Please don't do that.

Biodiesel is a great alternative to conventional fossil fuel petroleum diesel fuel. It has numerous advantages over petrodiesel like being good for the economy and the environment. It will also prolong the life of your engine, but that is only if you use high-quality Biodiesel.

To test the quality of biodiesel, first do a simple visual test. Check to see if there is any cloudiness, particles or films in your biodiesel. It should be translucent with the colour of vegetable oil with a light brown tint. The colour will depend on the feedstock used.

If there is cloudiness it could be because of water in the biodiesel. Slowly heating it up should let the water sink to the bottom where it can be drained off or heat it up to let the water evaporate. When it cooled down again the cloudiness should be gone, if not let it stand for a week. That should give enough time for any water to settle at the bottom. If there is particles in your biodiesel fuel try filtering it again, this time using a finer filter. Films in your fuel could be due to soapy residue still left. Try washing your fuel one more time.

Your finished product should have a pH of 7. Use a digital pH meter or a litmus paper to do this test.

Filter it one more time using a micron filter just to be sure.

After this you should have high quality biodiesel that will turn the petrodiesel companies red with anger and your neighbours green with envy.

Fill up your car, truck or generator, enjoy the feeling of freedom and know that you did your part to save the environment...