I have washed my biodiesel in a drum... I have 120L biodiesel in and washing 8 times with 40L of water...
This works very well but my washin water is still after 8 times washing a little milky... I dry it up 50 degress C. and it`S fine..

Now my questions goes...

If I put acid (vinegar) in the 3 times washing 100ml acid
then I only need to wash my biodiesel 6 times and my washing water is almost like normal water with no milky in... ?? hows that .. ? Some said that I backconvert the remaining soap into FFA. Maybe that`s correct don`t know but it works more ease to wash but will this be harmfull to put acid in wahing water ?

I have not done a 27/3 test for soap content after acid but I can`t see any differens in my biodiesel...

Getton....

First of all lets get something clear.

The 3/27 test WILL NOT tell you anything about your soap content at all.
The 3/27 test WILL tell you something about your dergee of conversion and nothing more.

Your wash water still being murky would suggest to me that your reaction is not fully complete and you still have some mono and biglycerides present.
A 3/27 test on some of your dried biodiesel is sure to comfirm this.

I would not add anything to your wash water, and it is not necessary if the rest of your process is sound.

Thanks for info... Yes I may still have some triglyci in it and my process is still not complete ... I have raisen the amount of KHO from 7 to 8 grams pr/ltr... + titration... so maybe I need some more KHO in the process...

Well I thought that a 27/3 would tell me the amount of soap remaining but I see I was wrong here.. But in the dry biodiesel I must see when I raise the amount of KHO in my next batch... THanks for info

Getton

Don't acidify your wash. I used to do it with KHSO4 as it seemed to speed the process up, but all I was doing was converting the alkali salts of the fatty acids (soaps) into the FFA form - and a heap of corrosiuon in my fuel tank was the outcome. I went through a million blocked fuel filters until I worked out what the problem was.

Thansk for info about Acid in washwater... I Think it`s a bad idea then.... So I just wash a lot it helps too... as you write.. acid=speed process up .. but i will stop with acid.

Thanks.... Getton