Hello Norman,
I think you're confusing two different techniques a little bit.
I was writing about the glycerol remix prewash, which is done in order to cut down on the soap that you have to wash out.
Once you're finished mixing your biodiesel in the reactor, you add 5% water to the reactor, mix again for couple of minutes to get it evenly dispersed, then let the glycerine settle normally. You will then have slightly cloudy biodiesel which has a lot less soap in it than if you hadn't added the water. The reason this works is that it makes the glycerine by-product scavenge more of the soap. This is because a more 'watery' glycerine by-product is more attractive to soap than the 'oily' biodiesel is.
You have to wash the fuel afterwards, the slightly cloudy appearance is a sign that some water gets into the biodiesel, so you don't want to use it without washing if you do this method.
I think the technique you're thinking about however is a different one. There was some technique where people discovered that adding glycerine to waste vegetable oil before making biodiesel somehow made heavy fats fall out of it, which then improves the cold-weather performance of oil and the biodiesel that is made from it. Basically, it makes fats settle out more completely. Most waste oil is made from both oil and fat, and the more solid fats make poorer-performing cold-weather fuel.
I think that the thread that you're looking for is this one:
http://biodiesel.infopop.cc/groupee/...9441081511/p/1
