Stolen from the Bio Diesel Discussion Forums

DR Pepper Technique (Pat Pend) as recommended on the Journey to Forever site

People sometimes ask about this procedure, and I can never remember where I have discribed it because I have always done it in some other heading. So with everyone's indulgence, I will discribe it here under it's own heading so it is easy to find.

The idea for the Dr Pepper Technique came about one day many years ago (it seems) when I was trying to figure out an inexpensive way of making a few test batches of biodiesel to see if it actually worked when out of the blue it occured to me to shake it up in a Dr Pepper bottle and that was the start of the Dr Pepper Technique (Pat Pend) and I did not use any ideas from Greg. 

I will assume that if you are reading this for the information then you are new to Biodiesel making, so just a few words of caution:

THESE ARE DANGEROUS/POISONOUS CHEMICALS. Common sense must be used. YOU ARE RESPONSIBLE FOR YOUR ACTIONS AND THE SAFETY OF YOURSELF AND EVERYONE/EVERYTHING AROUND YOU.

METHANOL IS AS FLAMMABLE AS GASOLINE/PETROL.

Before you make Your first batch of Biodiesel you should visit Mike Pelly's article on Biodiesel production, and follow all of his safety suggestions, and if approprate to your situation his titration procedure.

THE TECHNIQUE:

Take one litre of oil and heat to at least 120 deg c to remove all water. If water is present the oil will spit and pop and carry on. If there is a lot of water this could get very violent, so be careful.
Once the water is gone (Oil becomes calm and there is no more spitting and popping) let the oil cool.

While the oil is cooling mix your methanol and NaOH(lye) to form the methoxide. Use 200ml of methanol. 
If you are using new oil this will require 3.5g NaOH. Otherwise you will have to do a titration to determine the correct amount of NaOH OR just use 6g NaOH and hope for the best. 

WARNING: DO NOT MIX THE METHOXIDE IN A PLASTIC SOFTDRINK BOTTLE AS THE NaOH ATTACKS THE PLASTIC AND YOU WILL QUICKLY BE SHAKING A BOTTLE FULL OF HOLES WITH METHOXIDE GOING EVERYWHERE. 

Once the NaOH has all disolved it does not seem to bother the plastic bottle.

NaOH and Methanol do not readily mix, so if you are doing it by hand a bit of time and patience is required. Don't sniff the fumes. For quickest mixing, start with the methanol at JUST body temp (not warm). As you mix, the temp will increase substantially. This is normal. Make sure ALL the NaOH (lye) is disolved. This may take 10 minutes or more. Hand mixing can be accomplished using a spoon to stir/crush the NaOH granules; OR placing methanol/NaOH in a glass bottle with a top and shaking/ swirling until ALL NaOH is disolved. 
After ALL the NaOH has disolved, top up to 200ml with fresh methanol, as there will be some evaporation during mixing.

When the Oil's temp has dropped to around 60 deg c or less, using a funnel, pour the litre of oil into a DRY 2 litre Dr Pepper bottle (in a pinch any other brand of bottle will do). Take the mixture of methanol/NaOH (commonly called methoxide on this forum) and pour on top of the oil using the same funnel. Remove funnel. Screw the top down TIGHT onto the bottle.
Shake vigerously for about ten seconds. NO pressure is generated during mixing. 

Now place the bottle on a table and observe the oil change colour from a "Chocolate milk to a rich, darker brown." Then, as if by magic, within 10 minutes the by-product (commonly refered to as glycerine on this forum) starts to settle out and form an increasing layer on the bottom of the bottle. 
Within an hour, most of the glycerine will be settled out. This is referred to as seperation. Be sure to notice that you can see a very definate, slowly sinking line towards the top of the Biodiesel as the glycerine slowly settles.

You should now have a bottle containing lighter coloured biodiesel on top of a layer of darker glycerine.

If it does not work out come onto the forum and see if anyone can figure out what went wrong. 

And that is all there is to it. Only a little magic is involved.

Again, I strongly advise that before you make your first batch of biodiesel. read Mike Pelly's article on biodiesel production and follow ALL of his safety cautions.

A few cautions: DON'T mix the methanol and NaOH (lye) in a plastic bottle as NaOH attacks some types of plastic. Once mixed, the methoxide does not attack plastics that I am aware of, just the undisolved NaOH seems to attack plastic.

DO NOT allow any WATER into any steps of this procedure.

Methanol boils at about 65 deg c. DO NOT mix until the oil is below 60 deg c.

Again, these are dangerous chemicals and care is necessary, especially if there are children in your home. 

YOU ARE RESPONSIBLE FOR YOUR ACTIONS AND YOUR SAFETY AND THE SAFETY OF EVERYONE AROUND YOU.

I have Up-Sized the Dr Pepper technique by using a 20 litre plastic drum (longish and skinny) and make 14 litre batches. I simply lay the drum on a wooden "cradle" and place the center of the cradle on a pipe and rock back and forth for 3 or 4 minutes. 
I then decant the mixture into a "finishing" container and so am ready to process another 14 litres straight away.

Addendum: Since posting this article, 007 (neutral) has proven to my satisfaction through GC tests that although one 10 second shake produces very useable Biodiesel it is in fact not of ASTM standard. It appears that to produce this high quality fuel requires four- 5 second shakes over the space of an hour. 

Tilly SBC/IBA Dr Pepper Div   

"No job is so simple that it can't be done wrong".