The present volume, Volume 2 in this planned series on coffee, deals
with processing and follows on naturally from the first volume on the
chemistry of coffee, which described its numerous constituents in the
green (raw) and various product forms. We have already remarked that
coffee has great compositional complex- ity, and this complexity of
understanding extends when we come to that is, the many processes
involved in the roasting consider its processing; of green coffee and
its subsequent conversion into a consumable brew, especially through
extraction and drying into an instant coffee. The simple brewing of
roasted and ground coffee with water in the home also possesses
considerable mystique and needs know-how for optimal results. The choice
of green coffees from an almost bewildering array of different types
available, through species/variety differences and different methods of
processing from the coffee cherry to the green coffee bean, needs
understanding and guidance. Furthermore, various forms of pre-treatment
of green coffee before roasting are available. Some of these are little
known, but others such as decaffeination, for those who desire roasted
or instant coffee with little or no caffeine, are now becoming well
established. Finally, both the processing of coffee cherries to coffee
beans, leaving a range of different waste products (pulp, hulls, husk,
parchment, etc.), and of roasted coffee after industrial aqueous
extraction, leaving spent coffee grounds, provide waste products that
have found considerable commercial value in different ways.
