Preparing Used Cooking Oil for Biodiesel

Biodiesel is an inflammable biodegradable fuel made from animal fat or vegetable oil. It uses renewable resources which are eco-friendly, and generates less toxic greenhouse gases when burned. Biodiesel can be utilized in any vehicle that uses regular diesel fuel. With the appropriate equipment and the right safety measures, you can make biodiesel fuel using used cooking oil from your home or commercial kitchen. Here is how.

Acquire Used Cooking Oil

You may not collect enough used cooking oil in your kitchen. If you don’t have a commercial restaurant, you may want to make arrangements with cafeterias, hotels, fast food restaurants, and other commercial food facilities within your locality to collect the used cooking oil they no longer need for a small fee. Find restaurants which:

  • Utilize olive or canola oil because they are the best candidates for producing biodiesel. Remember, hydrogenated oils are not a good choice because they contain a high percentage of free fatty acids which can hinder the production of biodiesel.
  • Sell lots of fast foods since they can have large quantities of used cooking oil they need to dispose of.
  • While you may opt to purchase new cooking oil,  used cooking oil is less expensive and ideal when it comes to reducing waste and saving the environment.

Assess the oil

Assess your oil in order to establish quality. Your oil should be darker than unused oil and should have come food particles left as a result of the food particles. If it appears cloudy or milky, it could be due to a high percentage of animal fats or water content which can hinder the biodiesel production process.

In such a case, you may want to consider disposing of it. Follow appropriate procedures to dispose of your waste cooking oil. Contact your supplier or the local waste management company and find out how they dispose of their used cooking oil.

Pour the Waste Oil in a Clear Plastic Container

Empty your collected waste oil in a plastic storage container for storage. Ensure your container of choice is well cleaned, dried, and free from any residue such as food particles or even water. The container should have a tight fitting lid and free from cracks or holes to avoid leakage.

Even when your oil was delivered in an appropriate container, you will still need clean and dry containers to keep the oil after every filtration stage. Ensure all your containers and any other materials you use in this procedure are well labeled.

In this case, you will label your oil as either used or unfiltered oil to avoid getting confused during the latter stages of the preparation process.

Heat Your Oil to 95ºF

In a large and clean cooking pot, pour your oil and heat it up to 95ºF atop an electric burner. Monitor the oil temperature using a cooking thermometer. Avoid using a gas burner in this or any other stage of the biodiesel production process. You may want to execute this procedure in a well-ventilated place preferably outdoors.

Wear protective clothing such as safety goggles, an apron, and long rubber gloves. These will come in handy to protect against spillage or splashing. Remember, part of the oil will be lost in the filtration process. You, therefore, should heat more oil in order to produce your desired amount.

Pour the Oil Through a Coffee Filter or Cheesecloth

Put a coffee filter or a piece of cheesecloth on a funnel and place the funnel on top of a clean and well dried plastic container. Pour your heated oil through the funnel and in the container to remove any food particles. Label the container accordingly. Once this process is over, you can either discard the coffee filter or cheesecloth or rinse it out for subsequent use.

Reheat Your Oil to 140ºF

Pour the screened oil once again in a well cleaned and dried cooking pot. Place it on the burner and heat it for 15 minutes at 140ºF. This separates any present water from the oil. Monitor the oil temperature using a cooking thermometer to prevent the heat from rising beyond 140ºF. Give your oil time to cool down before pouring it back in plastic containers and label them accordingly.


This is an easy method you can use to filter used cooking oil in preparation for the production of biodiesel. After the filtration method, keep your filtered oil in clean and dry containers in readiness for the subsequent process.