Question: what is the difference between top fermenting yeast and bottom fermenting yeast?
Answer: Top-fermenting tends to yield more flavor, as esters (a byproduct of both kinds of fermenting) are more pronounced in warm fermenting, as are phenols (which include things like tannin). Lager, on the other hand, is bottom-fermented, meaning the yeast works at the bottom of the wort, at a much lower temperature.