I see now. This process is also called Kreusening.
It is a process used mainly by German brewers to comply with the Rheinheitsgebot, as under that regulation they could not add sugar to their beer, even a small amount for carbonation.
The process is also discussed on BeerSmith. Link :
http://beersmith.com/blog/2010/03/22/kr ... ewed-beer/Seems like a lot of work to me, but hey, whatever floats your boat is OK with me. I don't think it would make any difference to the taste, to be honest.