i know it may have seemed like an april fool's joke, but compost teas, compost wines and microbial brews are now at the cutting edge of organic growing techniques. I've been brewing my own recipes since the mid 1990's and grow wholly organically, with fairly impressive yields. when the RHS bods told Rachel they weren't sure what exactly was going on, but the science was complex - they hit the nail on the head!
Most scientific approaches to microbiology focus on pure (single) species, which are then isolated, grown in macro cultures (so they and their actions can be seen) and therefore only ever understood by their singular properties. Due to the sub-microscopic size, the way differing species interact, or work cooperatively together, can never truly be witnessed. You can of course see their combined effects in terms of the nutrients they cycle and how they change soil structure, chelate minerals, modify water retention, cation exchange capacity and so on...
The problems with compost tea come if you don't brew it right - if incorrectly done, you can introduce pathogens magnified many times and herein lies the mystique of getting the ingredients and the method right. a dark art, it is, much like alchemy
but if anyone has any questions, i'd be happy to weigh in with my experiences and knowledge...