Cold water washing....

[dgs]

I don't think that adding acid can increase the soap, it converts the soaps to ffa's which is why it washes easier.
BB, why not try to pump wash your next batch after you have mist washed it, you may be suprised what it removes. Just make sure your pump system is purged of glycerol before you do it.

Just been reading the posts on this thread properly. It is impossible to create an emulsion mixing bio/water however aggressively if the soap level is low. Some pump wash from the start, using initial small bursts of only 30 seconds, building up to 20mins over several washes.

I have never fitted my wash tank with a pump which is why I use the compressor, my 1st burst of air is usually 1min and over 4 or 5 washes build the time up to 20 mins. I try to leave the mix to settle for 30 mins between washes. When the wash times build up to 10 mins, after settling I notice the emulsified layer between the water and bio. This is removed after the water and set aside to settle. It totally separates after a day or so into about 2/3 to 3/4 water and the rest monoglycerides (lets call these 2/3 converted bio) The mono's are poured into the glycerol for the next wash.

The mono/water layer is never the same amount batch for batch. If the batch is just on the 'cusp' of the 10/90 pass, they will me more. If too much chemical has been added to the last reaction then they will be less. The longer the batch is mixed for then the less chance of getting a lot of them.

Getting rid of the mono's depresses the temperature at which the finished bio will mist/gel and is very dependant on the water level of the finished bio.

[Bio-boy]

I don't think that adding acid can increase the soap, it converts the soaps to ffa's which is why it washes easier.
BB, why not try to pump wash your next batch after you have mist washed it, you may be suprised what it removes. Just make sure your pump system is purged of glycerol before you do it.

I thought pump washing would be too aggressive and create an emulsion. If that is not the case then I may well give that a try. How long does it take for the water to drop following pump agitation?

[dgs]

I thought pump washing would be too aggressive and create an emulsion. If that is not the case then I may well give that a try. How long does it take for the water to drop following pump agitation?

Around 30 mins, but generally a longer time for longer washes.

[Bio-boy]

What prevents an emulsion from forming?

[dgs]

What prevents an emulsion from forming?

basically by washing in an appropriate manner/time for the amount of soap the bio contains.

I have only compressor washed for the last few years and have found if the de-methed bio is settled so that the soap is less than around 400ppm an emulsion will not form even if the 1st wash is 5 mins. I once tried washing my bio with soap at 1350ppm and got an emulsion within 30 seconds.

It's a bit of a balancing act doing a really aggressive wash, but once you know what you are doing it beats bubbling/misting every time.

[biobill]

I've always done an aggressive wash I use a 5 inch twin blade paddle running at 2850 rpm. I add 20ltrs hot water to 160ltrs of bio and wash 5mins first and 10mins second wash and the wash water
 settles out in around 5mins