I came across this 7 page article by one of the main guys behind the chemistry research at illycaffe whilst searching for new reading material and it is an interesting overview, though no doubt familiar to those who own “The Science of Quality”.
One section seemed relevent to discussions going on around these parts of late:
“To the young food chemist, espresso could be a challenge for deeper research, because its structure of a polyphasic colloidal system along with its complex composition may be seen as the quintessence of all other techniques by which coffee can be brewed. Knowing espresso is to know coffee in all its forms.”
Link to the pdf here.