BioDieselNow - Renewable biodiesel fuel

I'm nervous about using biodiesel in my car given the lack of consistency amongst comercial plants that exists, not to mention homebrew.  So lets say hypothetically, I get BD that is washed and dried thoroughly, but still has unreacted FFA's in it?  Worst case scenario what could that do short term or long term to my 01 TDI?  I'm half tempted to go buy an early 80's diesel, just so I won't have to worry about it.

Test is yourself using the 3/27 test.

I'm really looking for an answer beyond, "test it"  A.  I don't have the ability to keep a bottle of heet with me at all times while I'm on the road to test commercial sources, nor do I have the time to do that. I drive enough in my job that I pass a number of different suppliers.  I specifically want to know if anyone can tell me what risks are involved with running partially reacted BD in older VW engines, beyond fuel filter cloggs.  I get that you shouldn't do that, and that you should test your fuel for quality.  But does anyone have factual info on the risks?