Photo: Utah Biodiesel SupplyEven with the retail price of biodiesel hovering close to the price of regular diesel (“dino-diesel” to us bio-enthusiasts) in many areas, a growing group of DIYers are making the fuel from scratch in their own garages and back yards.

Homebrewing biodiesel has many advantages: it usually costs well under $1 a gallon to produce, it eliminates trips to the gas station, and it makes a hell of a hobby.

I’ve been making biodiesel in my garage for almost two years with equipment that I built myself from instructions available for free online and with used vegetable oil that I pick up for free from a local restaurant. But, we’re getting ahead of ourselves. Like most homebrewers, I started my bio-adventure by making small test batches of biodiesel in my kitchen.

Before we go any further, the the archive legal team has asked me to include a short note about safety:

Almost everything you’ll be dealing with when making biodiesel can be very dangerous. You’ll be handling hot oil, methanol (which is poisonous and potentially lethal if consumed, if it gets on your skin, or if its vapors are inhaled), and sodium hydroxide (lye, which is poisonous and corrosive if consumed or inhaled, and which will burn your skin quickly and painfully immediately upon contact). Always wear heavy-duty, chemical-proof gloves, eye protection, and a dust mask during every step of the process. With methanol, not even cartridge respirators can protect you from fumes. Always minimize the time that anything containing methanol is unsealed. Literally, hold your breath for the few moments that you’re working with open methanol containers. Above all, use common sense.

Biodiesel is simply heated vegetable oil mixed with methoxide (methanol + lye). The lye in the methoxide breaks apart the vegetable oil and allows a methanol molecule to recombine where a glycerin molecule used to be (methanol and glycerin are both alcohols). When the reaction is finished, the darker glycerin settles to the bottom, and the lighter biodiesel is left on top.

Here’s what you’ll need to make your own test batch at home:

• Safety equipment listed above

• 1 Liter of any virgin, unused vegetable oil (non-hydrogenated!)

• 1 bottle of “Red Devil Lye” drain cleaner, available at most grocery and hardware stores. Red Devil is very close to pure NaOH (sodium hydroxide), and is perfect for making small batches of biodiesel. If you can’t find Red Devil, contact a local chemical supply house and ask for sodium hydroxide.

• 1 bottle of “HEET” brand antifreeze (the yellow bottle) available at most auto supply stores. HEET is close to 100% pure methanol. If you can’t find it, look for a local racing fuels retailer that sells methanol.

• 1 large sealable glass jar or bottle, like a mason jar (at least 1.5 liters)

• 1 small sealable glass jar or bottle, like a mason jar (at least .5 liters)

• 1 glass (not plastic!) measuring cup (at least 250 mL)

• A scale that measures in grams

• 1 funnel

• 1 thermometer

• 1 paper cupcake wrapper

This “recipe” only works with virgin veggie oil. If you want to try making a batch from used oil, check out the external resources provided below. You’ll need to do a titration to determine how much lye to use.

How to make methoxide:

1. First, go outside. You’ll want to do this in a well-ventilated area. Measure out 250 mL of methanol (HEET). Pour it into the small glass jar and seal it.
2. Measure out 6 grams of NaOH (Red Devil). Don’t let the lye touch anything plastic or anything living, including you. You can use a paper cupcake wrapper on the scale to hold the NaOH if necessary. Lye tends to stick to anything and everything else.
3. Unseal the jar containing the methanol and carefully pour in the NaOH. Re-seal the jar.
4. Gently swirl the jar to dissolve the lye in the methanol. This may take a few minutes. The jar will probably become slightly warmer. This is normal. A small amount of pressure will also be built up. Gently vent this pressure outside by opening the lid, but do not breathe the fumes!
5. Leave the jar outside for now, but not in the sun.

Unwashed Biodiesel (with glycerine removed)How to make biodiesel:

1. Begin by heating the liter of vegetable oil to 140-145 degrees Fahrenheit on the stove or carefully in the microwave.
2. Pour the heated oil into the large glass jar using the funnel if necessary.
3. Take the oil jar and the funnel outside. Carefully but quickly pour the methoxide into the oil jar using the same funnel. Re-seal the jar.
4. After ensuring that the jar is completely sealed, shake the mixture vigorously for 20-25 seconds.
5. Set the jar down in a well-lit area and watch the magic happen!

You’ll notice immediately (probably even while you’re shaking) that the mixture turns a much darker color than the original oil. This is the dark glycerin molecules being broken off of the original veggie oil molecules by the lye. After just a few minutes, you’ll begin seeing the glycerin fall to the bottom of the jar. Within an hour or two, if all went well, all the glycerin should have separated out and you should have two clearly separate layers: dark glycerin on the bottom (20-25% of the volume), and cloudy looking biodiesel on top. Success!

Washed BiodieselCan you run back outside and pour the biodiesel directly into your diesel car or truck? Well, it’s probably not a good idea. The reason the biodiesel layer looks cloudy is because there is still some leftover lye and other impurities floating around in there. Though some homebrewers do use this “unwashed” biodiesel, most of us choose to take a few extra steps to “wash” the fuel of all the impurities before putting it in our tanks. You can see the clarity difference in the two images. The reddish unwashed biodiesel above is too cloudy to see the text behind the jar. The washed fuel on the left is almost perfectly clear. (Don’t worry about the color difference: they’re just two different kinds of vegetable oil.)

If you’re ready to learn more about making biodiesel, here are a few of the resources that helped me move from making small test batches to making 30 gallon, road-ready batches in my “Appleseed Biodiesel Reactor”, wash tank, and dry tank:

• The Collaborative Biodiesel Tutorial – Everything from building your own processor to using the leftover glycerin to getting restaurants to give you their used oil.

• InfoPop Biodiesel Forums – The greatest and most helpful homebrewers in the world hang out here. If you’re planning to become a homebrewer, trust me, you’ll need their help.

• Yahoo! Biodiesel Basics Group – More great information and knowledge from experienced homebrewers.

• the archive Resources: Check out our biodiesel archives, biodiesel in our Green Guide, and our residential biodiesel expert Clayton Bodie Cornell.

• My collection of posts about going biodiesel at The Higher Pie.

Utah Biodiesel Supply photo by Jack Jones, courtesy of Graydon Blair.