If all the fryer crap is filtered out, there may not be much for the germs to work with.
No, I don't think that's right. I think the germs eat the fuel itself. Even biodiesel made from pure vegetable stock is going to need biocide.
I could be wrong about that, though!
I continued to run that B100 in my VW TDI for about 15k miles, even though it was looking pretty soupy toward the end. Sounds reckless, I know, but it was an old car and I considered it an experiment, worth the risk, because I too had heard diesels could run on anything. The short term drawback was plugged fuel filters, so I started carrying a spare around. Some time after I quit and went back to "dino" diesel, my injection pump started leaking. I took it into a little shop in Cody that worked on foreign cars. He took the pump apart and asked me, "What the Hell have you been running in this thing?" He said the whole pump was a corroded mess. It took a lot of dollars to fix. Ah, the sacrifices I make in the name of science...
Anyway, my enthusiasm for biodiesel waned quite a bit. Now I still like it at B5 to add lubricity, but only fresh and from a reputable supplier. Not these little operations in the shed in somebody's back yard. B5 or B20 is now sold all over the Portland area by the big companies, so I think that is OK (although my new TDI Passat warranty says to use nothing over B5).
