So just what is a biodiesel reactor? A biodiesel reactor is the main part of the biodiesel processor, and typically the largest part of the processor as well. It's where all of the most important chemical reactions occur, and as such, the reactor must sustain temperatures above room temperature. When it's time for the biofuel to be made, the methoxide comes out of its storage tank, and the animal fat or vegetable oil comes out of its own tank, and the two substances enter the biodiesel reactor. Here, the chemical process of transesterfication will take place, which is to say that here the oil dissolves into the methanol and the glycerin is separated from the methyl esters. From the reactor the glycerin is pumped into its storage tank, and likewise the biodiesel fuel is fed out through pipes into a tank where it will be washed. There's also a vent leading from the biodiesel reactor to the outside of the processor; this vent will relieve any excess heat or pressure building up inside the reactor. Sometimes the reactor uses a centrifuge to speed up the chemical reactions that create the biodiesel fuel. These centrifuges are very expensive, however, and thus while they are common in fuel plants they are quite uncommon in home biodiesel processors.

Biodiesel reactors vary in many ways. They come in different prices and at different specifications; they come in various sizes and shapes and dimensions. Other points of difference between biodiesel reactors include how many liters of the methanol and oil-or-fat mixture they can process per minute, as well as the maximum temperature at which they can heat oil and methoxide. Biodiesel reactors also differ according to what their maximum voltage is (that is, how powerful they are). Some reactors have more pipelines than others. And some have metal frames while others don't. And while most biodiesel reactors are expensive and complex pieces of machinery, they can be as we will see in the next section as simple as an ordinary kitchen blender.

Biodiesel reactors can be bought separately from the rest of the processor, and often they come with their own owner's manual as well. Be sure to read the directions very carefully. While reactor maintenance usually isn't too difficult, you want to make sure that your reactor is always in good working order that the vent is clear, that there isn't any buildup clogging the reactor's parts, that the heater is working at all times.

Now, you might not have any interest in purchasing a biodiesel reactor. However, if you still want to try your hand once or twice at homemade biodiesel fuel, or you want to only make small quantities of biofuel on a semi-regular basis, then read on to discover how you can make biodiesel without any special equipment at all.