How to Make Diesel Fuel From Cooking Grease

Cooking grease or waste vegetable oil (WVO) can be filtered or allowed to settle in order to separate the oil from water and food particles. The separated oil can then be used straight in a diesel car with a conversion kit (two tanks) or as an ingredient in biodiesel. Waste vegetable oil works best for at-home preparation, but lard and tallow can be used as well.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Waste vegetable oil or grease
• Cheesecloth
• Large barrel
• Conversion kit (optional)
• Methanol or ethanol
• Lye (sodium hydroxide)
• Blender or industrial mixer
• Processor (optional)

Prepare the Grease

1. Filter the grease. Filtering is as simple as pouring the grease through a double cheesecloth to remove food particles. Some people choose to let the grease settle for several days since filtering a large quantity of waste oil can be time consuming (and sometimes messy).

2. Remove the water from the grease. Waste oil likely contains water that was added in the cooking process. This water can slow down the effectiveness of the fuel if left in the oil. Heat the oil to 212 degrees F and allow the water to boil away. This can be difficult in large quantities, so it is good to do a test batch first.

3. Decide how to use the grease. If you have a diesel engine with a conversion kit, meaning a second tank has been added for straight oil or a mix, then you can add the filtered vegetable oil to your car immediately. Converting to biodiesel is not necessary if you have a conversion kit.

Making Biodiesel

4. Get the ingredients for biodiesel. In addition to the filtered oil you will need an alcohol (methanol or alcohol) and lye (sodium hydroxide). Methanol can be bought at racetracks and paint shops. Lye can be found at hardware stores, chemical suppliers or some plumbing suppliers.

5. Mix the methanol and lye to create methoxide. These are dangerous chemicals, so it is a good idea to wear protective gloves and goggles at the least. Select a recipe from the links in the "Additional Resources" section to know the specific amounts of each item to use.

6. Add the vegetable oil and blend. For a small test batch, this can be done in an extra blender that you do not use for food. For a large batch use an industrial mixer or a processor made for biodiesel production.

7. Allow the mix to settle. Skim off the top layer before using it in your car. Do not use the thick mixture that settles at the bottom.

Tips & Warnings

• Establish a relationship with restaurants that will give you their excess waste oil and grease.
• Avoid being a biodiesel pirate. Do not take the used grease from restaurants without their permission.

Resources

• Biodiesel Step by Step
• Example Conversion Kit
• Biodiesel Recipe
• Biodiesel Recipe Calculator