In my search for locating a source oflarge amounts of yellow grease I was told that the free fatty acid level or ffa should be less then 5%. Most of the ffa levels from the sources or jobbers that I have located are mentioning around 15% in South Florida.

 Is this going to make a difference when trying to make the bio diesel?

Wouldnt this make the reaction possibly not happen and produce more glycerine or soap?

 

 

If FFA level is high you would benefit from and acid stage to esterify the FFA content prior to the base stage that will transesterify the oil.  If you skip the acid stage you will get soap production.