What is it? I have made two batches of bio out of soy wvo. One with a 3.5 g base and a second at 5.0 g. Both batches get a foam on top when drying. The foam gets no more than an inch or so. I washed each 10 gal batch 5 time. Each time with 5 gal. The fourth and last was may be excessive but I wanted to make sure it was clean. Both the 4th & 5th wash water was very clean. I am using naoh and 21% meth. First batch titrated at 2.75ml and second at 3.0ml. Any one that might know why I am getting a foam please respond. Do I need to worry about the foam? The first batch I scimmed it off and ran it, no problems. I did the 3/27 on both and had zero drop out even afetr 1 hour of sitting.