Debunking the Home Brew Myth

"Biodiesel Basis and Beyond" debunks many of the myths that currently surround the production of home brewed biodiesel. Here is one example:

7.1 Raw Biodiesel Production

While there is no doubt that a few home-scale producers are capable of making biodiesel that meets ASTM standards, there is currently no regulation or licensing of these hobbyist efforts, virtually ensuring that “off-specification” fuel is produced. Home brew operators vary in skill and production procedures from one location to the next, and none of the fuel samples I have examined meet the applicable standards. Ignorance, misguidance by Web peers, or lack of responsibility causes many people to engage in shortcuts or simply ignore the environmental aspects of the waste stream products, leaving those dirty little secrets hidden in the sewers, garbage dumpsters, and roadsides of the nation.

I would argue that micro-scale producers will operate in an endless vacuum of chat lines and open source forums that will propagate errors and misinformation unless this group can legitimize itself and tackle the hundreds of issues and myths that continue to circulate. I find it surprising that statements of fact are promoted and offered to people through online forums and “eco-fairs” and yet no one seems to bother testing these statements to ascertain their veracity. For instance, consider this statement from “experts” in the home brew community when they are considered in light of scientific and regulatory examination:

“Most of the alcohol (methanol) in the glycerin will evaporate if the glycerin is left in the sun for a week.”

To test this statement, a 200 ml sample (304.4 grams including beaker) of raw glycerol was weighed and placed in a warm, sunny location for a period of 10 days, after which the glycerol was reweighed to determine if any material had evaporated. The results indicated that less than 0.6 grams of methanol had evaporated in the “sunny location.” The glycerol was then heated to 70°C for a period of one hour. This ensured that the water would not evaporate but the remaining alcohol would boil off through simple atmospheric distillation. The sample was again reweighed. After heating, sufficient methanol had evaporated to cause the volume to drop to 175 ml and the mass to 281.4 grams. This test clearly indicates that very little methanol evaporation occurs without the addition of excess energy, thus refuting the statement above. According to the EPA Office of Pollution Prevention and Toxics, “Workers repeatedly exposed to methanol have experienced several adverse effects. Effects range from headaches to sleep disorders and gastrointestinal problems to optic nerve damage.” Given that methanol does not evaporate from raw glycerol, disposal, or downstream processing may present a severe health risk to people who are misled by such baseless information.

Figure 7.1- 1. “Most of the alcohol (methanol) in the glycerin will evaporate if the glycerin is left in the sun for a week.”4 To test this statement, a 200 ml sample (304.4 grams including beaker) of raw glycerol was weighed and placed in a warm, sunny location for a period of 10 days, after which the glycerol was reweighed to determine if any material had evaporated.

Figure 7.1-2. The sample was again reweighed. The results indicated that less than 0.6 grams of methanol had evaporated in the “sunny location.”

Figure 7.1-3. The glycerol was then heated to 70°C (to ensure that water would not evaporate but remaining alcohol would) for a period of one hour.

Figure 7.1-4. After heating, sufficient methanol had evaporated to cause the volume to drop to 175 ml and the mass to 281.4 grams. This test clearly indicates that very little methanol evaporation occurs without the addition of excess energy, thus refuting the claim above.