How to Make Pop Bottle Biodiesel

The use of vegetable oils for engine fuels may seem insignificant today but such oils may become, in the course of time, as important as petroleum. ~ Rudolf Diesel

In 1898, Rudolf Diesel was granted a US patent for his invention of the diesel engine but did you know that his original intention was for his engine to run off vegetable oil? He even marketed his invention to American farmers as a way for them to grow their own fuel. The process of making biodiesel is quite easy—so easy that you can make biodiesel fuel using inexpensive materials that you can buy at the grocery store. Here is how.


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    Obtain the necessary ingredients listed below.
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    Work outdoors in an open space. There must be adequate ventilation. Take proper precautions, such as wearing gloves and protective eyewear. And use the same precautions listed on the labels of the ingredients, in addition to your common sense.
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    Add one cup or 250ml methanol to a pre-measured glass container with a non-aluminum lid. Add one and a half teaspoons of lye.
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    Use an airtight non-aluminum lid and swirl or stir until the lye is completely dissolved.
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    Pour four cups of new vegetable oil. Heat the oil to about 60ºC or 140ºF.
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    Use the funnel to pour the heated oil into a 2 liter (0.5 US gal) plastic bottle. Add the methanol/lye mixture.
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    Tightly close the lid and shake vigorously for about 20 seconds.
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    Watch the formation. Through a process called transesterification, you will see a dark layer of glycerin forming beneath the lighter layer of biodiesel fuel, as the trans-fatty acids in the oil are stripped of one molecule of glycerin, which is replaced with three molecules of alcohol.
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    Wait. Over the next couple of days, you will see your biodiesel become clearer. This occurs as all the glycerin settles.
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    Use in diesel engines. This biodiesel fuel will work in almost any modern diesel engine. Ask your mechanic if you have any rubber hoses or gaskets, and have the mechanic replace them with synthetic. Biodiesel will dissolve natural rubber and that will end up clogging your filters. It has substantially reduced carbon emissions.


  • Biodiesel can be made just as easily from used oil provided the oil is first heated long enough to drive off dissolved water. Most restaurant waste oil does contain water. Failure to drive off the water will result in a useless gelled mess.
  • With over 30 million gallons of waste oil being generated by fast-food restaurants in the USA alone, it only makes sense that we put this to good use. There are a number of individuals around the world who do just this and run their engines off nothing but biodiesel fuel. See How to Prepare Used Cooking Oil for Biodiesel


  • Do not sniff or breathe the fumes.
  • Lye (sodium hydroxide) reacts strongly/vigorously with aluminum, generating heat (exothermic) and flammable hydrogen gas. In a closed container, it can generate enough pressure to rupture/explode the container. (See ANL note)
  • Sodium hydroxide can cause blindness in seconds. It hydrolyzes protein quickly, leading to severe eye damage. Cataracts, glaucoma, adhesion of the eyelid to the cornea, blindness, and loss of the eye may occur after eye exposure.
  • If you have a warranty on your vehicle, check to make sure that using biodiesel won't void it.
  • Flush exposed or irritated eyes with plain water or saline for at least 30 minutes. Remove contact lenses if easily removable without additional trauma to the eye, otherwise sodium hydroxide trapped beneath the lens will continue to damage the eye. If pain or injury is evident, continue irrigation while transferring the victim to the hospital.
  • Lye (Sodium Hydroxide) is a strong base (alkaline) and will cause serious burns to the skin in a very short time and can cause blindness in SECONDS if splashed in the eyes. Chemistry-style goggles should be used whenever using Lye.
  • If skin is exposed to Lye, it will first begin to itch, then a burning sensation will set in. If exposed, flush with cold water for several minutes.
  • For more information about safety and handling Lye, see

Things You'll Need

  • Methanol - this is used in a common product for removing water from your fuel lines, 1 cup/250ml
  • Sodium hydroxide, commonly known as lye, one and half teaspoons
  • Vegetable oil, any type, 4 cups
  • Glass container
  • Protective gloves and eyewear
  • Saucepan
  • Thermometer
  • Funnel
  • 2 liter (0.5 US gal) plastic bottle

Sources and Citations

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