I started extracting a few years back when i found myself with large amounts of trim.
place trim ice and a gallon jug and you can watch the trichs fallout
in the last 2 yrs I have tried every extract method that i have heard of even suggested. so far the bubble bags are the most efficient and quality per quantity is good. I started looking for HOPS extraction and perfume extraction the research is there in those fields and CO2 is proven method for extraction.
i will try steam extraction soon going to build a still and see wont be hash but should be a pure extract. when he book shows up the SCIENCE will continue.

http://www.oilganic.com/books/Superc...pounds%20.html