Biodiesel indepth FAQ

1. First, how do you prepare to brew biodiesel?

Our homemade biodiesel processor was made from a combination of recycled materials and local hardware store goods. The same can be accomplished by anyone with a concern for the environment and a vision for sustainability. By running our car on home-brewed biodiesel made with discarded vegetable oil collected from local restaurants, we are taking one more step towards self-sufficiency.

What sort of equipment do you need? The process of using a water heater to make biodiesel makes it safer and easier for backyard brewers to produce their own biodiesel as it compacts the entire heating process into a smaller space and eliminates dangerous hot fumes. The parts that are required are easily available for purchase from local hardware stores or internet sources

There are many methods to brew biodiesel and we chose to build our own using Maria Alovert’s water heater processor method described on our website at (includes photos)

How much does it cost and where do you buy it? For the processor equipment, the cost is less than $300. If you find a used water heater in good shape instead of purchasing one, the cost can drop to as little as $150.

Biodiesel Processor:

Plumbing, tubing, pump – $150-$200

New 50 gal. electric water heater – $200
(Cheaper or free, used ones can be obtained from plumbers or classified ads)

Full system:

Standpipe wash tank – $20-$30

Methanol recovery still – $20-$30

Bubblewashing equipment – $20

Drum for oil handling – $30

Piping for methanol recovery – $30

2. Once you have the equipment, what are the steps to brewing it?

Making home-brew style biodiesel begins with the collection of waste restaurant grease that local restaurant owners are generally eager to part with.

After collection, the oil must be filtered to remove any food particles in suspension and tested with a “titration procedure.” This helps determine the free fatty acids contained in the waste vegetable oil and also determines how much catalyst the oil needs. The presence and amount of free fatty acids depend on fryer conditions. It’s best to titrate to eliminate the risk of having a failed batch due to incomplete conversion.

The oil is then heated in an appropriate reactor vessel. Once the oil has reached 120° – 130° F, methanol and lye (at appropriate measurements determined by the titration procedure) are then mixed in a separate vessel and added to the heated oil once a homogenous solution is obtained. The oil/methanol/lye mixture is then agitated for ~1 hour and allowed to settle. This causes the glycerol to settle out and be drained off.

It takes approximately 24 hours for 30 gallons of finished biodiesel. However, most of this is heating, settling, and washing. An experienced biodiesel maker needs to only be involved in the process for about 2 hours of that 24 hours.

What is left is bubblewashed to remove any remaining impurities. The fuel will require a couple of washings until the water is un-clouded and measures the same pH as the tap water.

Once the biodiesel is washed it is allowed to settle/dry and evaporate the residual water out of the fuel. Before fueling a car, the biodiesel must be filtered to remove any abrasive particulates. This is achieved by using a common water filter.

Safety is ALWAYS important! The danger to the homemade biodiesel manufacturing process is the handling of the ingredients. Both lye and methanol are highly toxic. Lye will burn skin upon contact, and will do severe damage upon ingestion and prolonged inhalation as well. Methanol can be absorbed through the skin and cause nerve damage. It can also be fatal if ingested and cause blindness when in contact with eyes.

Proper safety equipment such as goggles, glove and long sleeve shirts is STRONGLY recommended.

3. How much do you have to pay for the raw ingredients (assuming one can’t get them donated)?

After the initial investment in equipment, it is estimated that biodiesel costs anywhere from 50 – 75 cents per gallon to produce.
Using wvo (waste vegetable oil) that we get from a local caterer, including the cost of lye, methanol and electricity.

4. Where do you go for a fill-up?

Our garage! We wheel out a 55 gallon drum that contains homebrew biodiesel and we fill ‘er up.

5. What kind of performance differences (if any) do you notice between diesel and biodiesel?

Biodiesel improves diesel engine efficiency and life. Biodiesel’s superior lubricating properties reduces wear on the injector pump and engine. Range, power, payload, and performance is equivalent to petrodiesel.

6. Are any modifications to your vehicle necessary? No. Biodiesel is the only alternative fuel that can be used straight in the fuel tank of any vehicle with an existing diesel engine. Biodiesel works in existing diesel engines with little modifications and no conversion needed.

7. Why did you opt to go the biodiesel route, rather than buying an electric or hybrid?

For our large family and hauling needs (like straw and produce) we needed a larger car. We opted to buy a used diesel car and brew our own fuel.

8. What’s the best way to get started with biodiesel if you don’t know anyone who can help set up a home brewery?

Check out our website there you’ll find a link to Maria “Mark” Alovert’s homebrew tutorial

9. Any special tips or advice I’ve forgotten to ask about? Any choices that need to be made regarding the equipment, or is there pretty much just one method?

The concept of using vegetable oil as an engine fuel dates back to 1895 when Dr. Rudolf Diesel developed the first diesel engine to run on vegetable oil. At the 1911 World’s Fair in Paris, Dr. Diesel ran his engine on peanut oil and declared ‘the diesel engine can be fed with vegetable oils and will help considerably in the development of the agriculture of the countries which use it.”

Vegetable oil seems to be the perfect replacement for petro based diesel, except for the fact that it has too high a viscosity for use in most existing diesel engines as a straight replacement fuel oil. This means you can either modify the engine to deal with high viscosity oil or process the oil to reduce its viscosity and we discuss the two options below:

Straight Vegetable Oil

One way to use vegetable oil as a fuel is to modify the vehicle so that it heats up the oil before it is used in the fuel system. Heating vegetable oil to 150F will reduce the oil’s viscosity sufficiently for use in a diesel engine.

It is possible to use Straight Vegetable Oil (SVO) by mixing the oil in with petroleum diesel so the vegetable oil acts as a fuel “extender”, but this is not recommended for long term use.


The other way to fuel a diesel engine with vegetable oil is to reduce the oil’s viscosity before it gets into the tank and in this way, neither the engine or vehicle needs modification. Biodiesel is the name of a variety of ester-based oxygenated fuels made from vegetable oils or animal fats. A Methyl ester of vegetable oil or what we now call Biodiesel is very similar to normal petrochemical based diesel fuel.

Its viscosity is only twice that of diesel fuel and its molecular weight is roughly 1/3 of vegetable oil, hence it can be used as a straight petro-diesel replacement. This reduced viscosity vegetable oil is now called Biodiesel with a number of standards like the European EN 14214 standard and American ASTM standard defining exactly what the properties of that oil should be.

The powerful thing about biodiesel is that is available now to an average person with an awareness of the environment. Being environmentally friendly doesn’t mean you have to invest in a $20,000 + hydrogen car.

Through the commitment of backyard biodiesel brewers, the petroleum addiction is being broken and the Alternative Fuel Revolution is infiltrating the mainstream. It’s a closing of the circle. By not extracting energy from the center of the earth and expelling it into the atmosphere, we aren’t introducing additional heat/energy/carbon mass into our system. It is a system that is renewable, accountable, locally grown and manufactured. So, is biodiesel going to save the world? No, but it is one step towards that goal. We’re not saying it’s the answer but it is one thing we can do – here – now – on our own.

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