How to Make Biodiesel at Home

April 10, 2012

Learn how to make biodiesel at home, what to look for in biodiesel kits, and how a biodiesel machine works.

Making biodiesel at home is actually not that difficult. It only requires some special equipment and a little financial output. Any cooking oil can be used but the favorite is vegetable oil. Vegetable oil does have a higher viscosity than diesel fuel or petroleum so it does need to be treated prior to using it in your diesel car.

Making Biodiesel at Home


The process for making biodiesel at home requires preparation and safety. Remember to wear protective clothing and safety glasses, especially when dealing with sulfuric acid and methanol. After you have collected all the used cooking oil into the filtration tank, use the filtration system to remove all particles from the oil. Used vegetable oil accumulates tiny bits of fried food and other particles during use. These need to be completely taken out before the process can continue.

Water Reduction

Once you have filtered the vegetable oil, heat it to around 60 degrees Celsius to expel any water that many have crept in during use. If any water has accumulated it will rise to the top or sink where it can be drained out.


You need to be very careful at this point. Methanol is highly combustible and extremely dangerous to touch or inhale. This is where you need to put on your gloves, overalls, respirator mask and safety glasses. Getting any methanol on your skin can cause serious harm. The ratio of methanol to oil is about 8 percent, so measure carefully exactly how much oil you have. Calculate the ratio and add enough methanol that it covers the 8 percent required in your total mix.


Calculate one-half of 12 percent of the volume for this stage. Remove the mix from the heat and keep stirring. Add the methoxide and stir it for approximately 20 minutes.

Sulfuric Acid

Without being repetitive, you cannot be too careful when handling these chemicals. Always take every safety precaution possible. Keep the safety clothes on when doing this next stage. For every ¼ gallon of oil, you need to add 33 fluid ounces to the mix. Heat the mixture to about 35 degrees Celsius and keep stirring the whole time. This part can be tiring. You need to keep stirring for approximately two hours. If you have a slow mechanical mixer you can use, all the better.


It now needs to be left to totally rest for approximately eight hours. This process causes the production of glycerin, which becomes separated and sinks to the bottom of the storage tank. Just as a point of interest, you can keep the glycerin and make soap with it if you are into recycling everything. Now you have made biodiesel.

How Does a Biodiesel Machine Work?

Basically, a biodiesel machine uses pressure with high levels of compression to extract biodiesel from a number of sources. The compression in these machines creates both a product and byproduct. Depending on the size of the machine, and the product fed into it, a biodiesel machine is capable of producing from 250 to 3,000 liters of oil. The actual process and machinery can vary depending on the size, the needs of the user and what raw product is going to be used.

The Batch Process

When it comes to biodiesel production, a lot relies on the method used to make it. One of the most common ways is known as the batch process. This method involves paying close attention to the free fatty acids as well as the water that goes into the system. If it is too high, there will be issues with the formation of the soap and with glycerin separation. A catalyst is dissolved into alcohol. This causes a charge to go through the vessel in a closed reaction. From there, the bio lipids are added. Mixing is done in a way where there is no loss of alcohol. This means that there's no contact with the atmosphere and it's kept at a certain temperature to prevent the alcohol from boiling. When alcohol boils it diminishes quite a bit. If there is no alcohol in the mixture, it will not be able to do its job properly.

The Microwave Method

Another method is the microwave method. A microwave oven is used to provide the heat needed for the transesterification process. Microwaves can provide a localized heat and can easily become higher than the temperature of the actual reaction vessel. A lot of the same steps are taken as in the batch process.

How to Choose the Best Biodiesel Filter

In order to properly process biodiesel, you need to have a biodiesel filter. You may in fact need more than one to completely clean out the biodiesel, but choosing what variety to use can be very tricky. Biodiesel can be made from a variety of different materials, from corn oils to vegetable matter, and the biodiesel filter needs to remove all of that before you can proceed any further.

Fuel Type

Before you start looking at the different types of filter on offer, consider the kind of fuel you will be using to power your engine. The heavier the fuel, the more likely you will need a significant filter.

Chemical Compatibility

Whenever you are working with biodiesel filtration, make sure that the filter itself is able to withstand the exposure that goes along with specific chemicals. These chemicals include alkaline solutions, solvents and acids. A filter of lesser quality will break down when there is exposure to these chemicals.

Filter Rating

The filter rating for biodiesel filters is typically graded in microns. A micron is one millionth of a micrometer. This rating tells you what specific sizes will not be able to pass through the filter medium. For some of the best filtering properties, look for at least a 5 micron rating.

High Temperature Properties

Just about any type of filter media that you come across will be able to be used for water-based products. However, when working with high temperature products, such as resins and hot oils, you need to look for a filter that can handle extended high temperatures. A biodiesel filter is going to have to deal with high temperatures on a regular basis.

What Comes in a Typical Biodiesel Kit?

If you are considering purchasing an at home kit, there are several components that you should ensure come with the kit.

Biodiesel Filters

Processing biodiesel require a filter to get a high quality end product. The filter must be designed to withstand high temperatures, as producing biodiesel fuel will require prolonged exposure to heat. A good filter will be able to remove most of the contaminants. A rating of 5 microns is preferred, but for low or mid range biodiesel kits you can expect a micron rating of around 3. It's also important to remember that the filter needs to be able to withstand different chemical exposure. Solvents, alkaline solutions, and acids are used to break down the product in to biodiesel.

It is not uncommon for a kit to come with several filters. This allows you to process the diesel through the filters several times, giving you a higher quality fuel blend in the end.

Biodiesel Processor

The processor is the most important aspect of a typical kit. This is the device used for turning the beginning product in to a usable biodiesel fuel. It takes the crude material and breaks it down. The process can take anywhere from 6 to 12 hours. The processor is usually the most costly element of a biodiesel kit, and most kits are rated based on the processor they include.

Safety Equipment

Many kits include basic safety gear. If yours does not, you need to invest in it. The fumes created by biodiesel are dangerous. They have been linked to blindness and death. Some kits include some type of fume or odor eliminator, but a respirator is still necessary. You should have rubber gloves and safety glasses as well. Biodiesel kits may come with everything you need to make a single batch, but you may need to invest in some good safety equipment as well.

Detailed Directions

A good biodiesel kit is going to include clear and detailed directions. You need to know how to set up the kit components, what products you can use and how to mix everything with different media. If you are looking at purchasing a kit, be sure it has clear instructions. These kits can differ from each other, and there is no single set of directions that will work for each kit.