Thanks for the feed back on my problem. For the record this is the first year in my 6 years of making Bio that i have had the problem. I water wash, don't know how to do a soap test other than to shake and look for the fine line between water and fuel.
I make 200 liters at a time and do a two stage process (18 liters methanol/675 grams of lye), heat oil to 130 degrees, mix in catalyst and mix with a pump for 1 1/2 hours.
Take a small sample and let oil and sample set over night. Next day drain glycerin and do 3/27 test of sample to see how much oil drops out. Usually 1 1/2 ml of oil drops, that means oil is 1/2 processed. If more I have to adjust amount of catalyst for 2nd stage.
I don't know how much glycerin drained off as it is thin and mixed with a small amount of fuel and won't harden for a while. It ends up about 8-10 gallons I guess.
I don't do titration. That is too high school textbook for a "backswoods" fuel making. Never found a PH meter that worked and PH strips? Forget them!
I do use a little clear vinegar after each rain water wash to make water drop out. Works great! Don't know what PH of fuel ends up being. Probably 7 or 8. After air drying fuel is a beautiful amber color and clear. My cars love it!
I did have a bacteria problem at same time (black specks in filter) but Biocide cleared that up. I have drained the fuel tank twice and gravity fed fuel through a primary filter and nothing showed up in the filter. With fresh fuel in the tank problem reoccurs. Must be warmth and agitation causing this mothery growth, but how to stop it?
Sorry for the winded reply but hti is basically all I know about Bio Diesel making and the problem I am having.
Thanks for helping.