BioDieselNow - Renewable biodiesel fuel

I know this is in relation to my last post but I figured this was a more direct question. 

Does the level of free fatty acids matter in the production of Bio Diesel? 

Yes.  The more FFAs there are, the fewer triglycerides there are.  Depending on your process, you will either have to neutralize the FFAs, or use a acid process to convert the FFAs back into triglycerides before you can perform the trans-esterification .

 Ok, can you please elaborate on this a bit

If ffas are at 15-20% what needs to be done? What % should they be at for optimal operation?

 The lower the better.  High FFA oil can be used, but it is harder to work with, takes more time and usually has lower yeild. 

Ok, point taken, what % is considered to high? 

 I normally think in KOH titration #'s and 7 is considered the cutoff above which acid base processing is needed.  I think 7 KOH is about 4% FFA.  HTH.

 My oil titrates at 1 KOH.