However, as I pointed out, the process I am promoting is NOT a static system and all the arguments brought up by Al are not relevant.
The unique screen pickup in this system does not demand a well settled grain bed to provide a clear run-off. Therefore the entire mash can be thoroughly stirred and mixed at regular intervals during the sparging process. This breakes up any channels that may have developed and redistributes the mash within the water column. I suspect that this would actually provide a much MORE effective extraction regime then depending on the number and location of outlet points.
What seems to make this point so hard to grasp is the fact that the other systems all have large spaces under the grain bed that must be cleared of turbid wort before sparging can actually begin. Wort is recirculated, there are painfully complicated systems for flushing these areas out and endless discussions about how much wort must be recirculated to get it to work.
The EM system runs clear after only a few ounces are drawn off initially and continues to run clear even after thorough stirring of the mash.
Back to Al's description of lauter efficiency