The chart above shows the simple transesterfication recipe in this particular chart the recipe is very accurate to two decimal places. For the average homebrewer there will be no need to measure to this accuracy nor will you have a way to without blowing your budget. The homebrewer will find that 1lb of oil will yeild 1lb of biodiesel, or 1L of oil will yeild 1L of biodiesel if the oil is reacted correctly.

You should also note the amount of methanol is 20% by volume of oil, therefore if you have 100gal of oil you would use 20gal of methanol and if you had 1L of oil you would need 200ml of methanol. As you begin to produce fuel you may find that your proccess is better using 21% or perhaps 19.5% methanol. Often times this small difference in the amount of methanol used can keep the biodiesel from becoming gell or perhaps the humidity forces you to change this number. There are many factors that go into this small difference in the amount of methanol like, humidity, air tempature, feedstock, loss of methanol during transfer and mixture. Methanol is currently around $4 per gallon and as you can see there is quite of bit of what is called excess methanol about half of the methanol you used to produce the biodiesel. This methanol is free and ready for you to take back. You can reclaim it by heating your biodiesel to boiling point of methanol and much like an old moonshine still you can distill the methanol vapors that boil out of your biodiesel. Often times these vapors are condensed into methanol that is not pure enough to just reuse therefore you may have to distill the distillant again to get a better product.

The next ingredient is NaOH or KOH either of which are suffcient. Either of these ionically bonded chemicals are mixed with the methanol in an amound determined by the titration. The titration is a way to measure the amount of NaOH or KOH needed to convert a specific oil to biodiesel. See the titration page for more info on this topic and how to perform the needed labwork.

This brings us to our next topic which should you use NaOH of KOH? The answer is completely up to you both chemicals will do exactly the same thing however with KOH you will not produce the amount of soaps that are produced with NaOH. Both chemicals are salts and both are basic, you should base your decision on which one to use based on the avialability in your area and the costs. However you should be sure to do your titration with whatever chemical you are using for example if you are using KOH do all your labwork with KOH not NaOH.

 If you are reading this it is probably becuase you are looking to kick the petrodiesel addiction at above $4 per gallon it is a very expensive one. This brings us to another very important advantage biodiesel has over petrodiesel; biodiesel can be often be produced for less then purchasing petrodiesel espiacally for the homebrewer. When rudolph diesel invented the diesel engine he displayed it at the world fair in Paris France and the engine ran flawlessely for weeks on peanut oil. This peanut oil was the predecessor to the biodiesel we know today. When the oil companies saw that the diesel engine was going to be succesful they jumped on board and offered up what was then considered a byproduct. This "byproduct" was much cheaper then the peanut oil Rudolph Diesel orginally used. Ever since that time petrodiesel has been significantly cheaper then vegetable oil based fuels. However now we begin to see that biodiesel and renewable oil based fuels can be produced locally and are normally cheaper then petroleum based fuels.

The above chart shows the relation between diesel consumption, diesel price, and biodiesel consumption. As you can see this data is somewhat dated becuase when was the diesel price at $2.70, if it were that still you probably wouldn't be on this site. The purple line which is denoting millions of gallons per year of diesel consumption, as price rises consumption slowly rises. We also see that as the price rises biodiesel consumption more then doubles each year. From this data it appears that biodiesel consumption is on an exponentail growth curve. The biodiesel market will continue to grow as the price of diesel fuel increases.

You are probabaly wondering just what a gallon of homemade diesel costs, well you should find with current methanol prices you will have about $1 in methanol for every gallon of biodiesel. You then must consider the electricity and catalyst both of which are minimal compared to the costs in methanol. Of course if you invest in this project you will have the cost of the equipment the space the equipment takes up and your time in building the equipment and running the batches.

 The National Biodiesel Board (NBB) mandates that all biodiesel produced meets ASTM specification. This is a quality assurance and in order to obtain tax incentives or sell the fuel the ASTM spec must be met. Often times the homebrewer is not trying to meet ASTM spec as it costs to much to get the fuel tested (about $1000) and even if he did meet the spec and claimed the incentives then he would have to play by the governments rules. See the page on for more information on testing for quality and ASTM test.

The four steps above are the simpliest way to make quality biodiesel. Remember this is only to give you an idea this is should not your only source before jumping into this project. Steps 3 and 4 above could be eliminated but without washing the fuel you will run into some major quality problems. The first step above is the processing of the oil the oil is heated to around 130 - 140 degree F this can be accomplished by an electric heating element, a propane burner, or perhaps a steam jacket. Once the oil is heated and the methanol and catalyst is mixed to form methoxide then you are ready to mix the oil this can be done with a paddle stirer or a pump recirulating the liquid from the bottom of the tank to the top. As the Methoxide is added be sure that if you used an electric heater it is off as methanol fumes around an element could cause an explosion and if you used a propane burner you should turn it off before you start handling methanol as you don't want a flame anywhere near methanol fumes or the liquid itsself. It is very important to respect all safety procedures! As the biodiesel and methoxide mix you are creating a mythl-ester which is the formal name for biodiesel. After the reaction takes place could which could take longer then an hour depending on how the liquids are mixed you are ready to turn everything off and let the mixture just sit in the tank.

That brings us to the next step above, after about 12 hours of the mix sitting in the tank with no agitation you will find a seperation. The heterogenous glycerin finds it's way to the bottom of the tank as it is heavier then the biodiesel that floats on top. This glycerin layer is the byproduct and is drained off of the bottom of the tank and disposed of. To learn more about what to do with the glycerin see our page on the byproducts of biodiesel. After the layer is removed from the tank you are left with biodiesel in the tank, this biodiesel is crude and most likely not of quality to pour into your engine. The picture below is of glycerin being drained from the bottom of the processor after settling.

 After the glycerin is removed there must be a process to clean and purify the mythl-esters. This can be done a number of ways a water wash can be performed which is pictured above in the process charts, a resin wash, or perhaps a bubble wash. The water wash is performed by misting water over the biodiesel, water is heavier than biodiesel so it will settle to the bottom much as the glycerin did. As this water settles out it passes through the biodiesel and picks up impurities such as residual catalyst, excess methanol and soaps. Once the water settles it is drained the same as the glycerin was, you will find that the wash water is white and soapy this is due to the impurities it removed from the biodiesel. This wash technique should be repeated untill rather clean and clear water is removed.

When the water settles to the bottom of the tank not all of the water settles some will become in solution with the biodiesel this yeilds a very milky appearance to the fuel. The fuel should be dried by heating it and allowing it to circulate for a few hours within the tank. This process relies on evaporation of water therefore you want the fuel to have the maximun surface area to the air. You will know when the drying is complete as the fuel will turn from the milky color to more of an amber tone. See the picture below which show the difference in the wet and dry biodiesel. The fuel to the far left is unwashed fuel, the middle beaker is the washed and dried fuel, and the right beaker is wet biodiesel. The layer of white in the far left beaker under the wet biodiesel is wash water.