Can you point to a recipe?
Try here: http://www.biodieselcommunity.org/
ALL CHEMICALS USED IN THIS PROCESS ARE DANGEROUS!
Employ appropriate safety measures while handling any of them.
The recipe for biodiesel is to test the oil (titrate) for the amount of catalyst required, heat the oil to 135-140*F, mix the methanol (20% by volume of dry, raw, strained, settled, used cooking oil) and lye (I use NaOH, so my base # is 5 to which I add the titration number).
Example: for 20 gallons of oil titrating at 2.5g/l you would use (20 x 3.785 - gallons to liters) x (5g base + 2.5g titration) = 567.8 grams of NaOH @ 100% purity.
This batch will require four gallons of methanol @ 20%. Pour the full, measured amount of NaOH into one or two gallons of methanol and agitate until all crystals are completely dissolved, then top off with the remaining two or three gallons and mix well.
This is your METHOXIDE. IT IS EXTREMELY POISONOUS and DANGEROUS to handle.
Add methoxide slowly to the preheated, recirculating oil and let agitate for at least two hours after all the methoxide has been added. Stop the recirc pump and let the glycerol settle for 6-8 hours then drain off the dark glycerol layer (the glycerol is dark and the biodiesel will be much clearer and lighter in color) which will approximately equal the four gallons of methoxide plus the titration number in percentage of the 20 gallons (2.5% of 20 gallons). The total glycerol will be approximately four and a half gallons. The remaining is the unwashed biodiesel.
From there, one can water or dry wash the fuel to remove remnant soap and methanol. I use water washing.