I normally water wash after doing my version of the 5% prewash method. I use a mixed Potassium and ASM catalyst which gives me a conversion yield of 102%
I do however have an indirect injection vehicle for which I bubble, settle and dry wash my bio. Using Potassium I find after de-mething for 24 hours, then selling for a day or two the soap level is between 250 and 850ppm. Sometimes if it is on the high side it is difficult to reduce the soap by further bubbling and settling.
On a recent small batch I used ASM for the 2nd stage (a very small 2nd stage requiring only 50mls of ASM) I bubbled for only 12 hours and after a settling period of only 3 hours the soap was down to 250ppm. I know from others how quickly the soaps settle using Sodium. I'll have to try this again.
