Coffee Technology – coffee, processing and naturally

Preface

Coffee Technology, 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 complexity, and this complexity of understanding extends when come to consider its processing; that is, the many processes involved in the roasting of green coffee and its subsequent conversion into consumable brew. especially through extraction and drying into a 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 other 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 (pulps, hulls, 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. (Coffee Technology)

In our nine chapter, therefore, all these subjects are dealt with in detail, bringing together much information that has not generally been available previously in the English language. Particularly, in the basic unit operations of roasting-grinding-extraction-drying, the approach has been that of considering of the fundamentals of the subject, through the well-established discipline of chemical (food) engineering. This approach to coffee processing has been applied by a number of workers in the last two decades as described in the Appendix (section 5); through, as will be seen, much remains to be revealed and understood in the complex field. Much information and opinion is empirical, so that, particularly in instant coffee manufacture, there are many elements of craft, skill and know how in the plant operation. however, it is not the aim of this volume to cover these facets, and indeed much of this is necessarily known only to the manufactures themselves, though an indication known only to the manufactures themselves; though an indication of prefereed or “wished-for” modes of operation can be seen on studying the numerous patents (probably some separate 1000) on coffee that have been granted. Only a selection of these patents can be given in this volume, with a preference towards noting the patents granted in the USA, though many of these may well also be issued in other countries. There is no doubt that the intense competition among the major instant coffee manufactures of the worl has been the spur to great progress in the quality of coffee products over the last three or four decades. (Coffee Technology)

A vexing problem common now to all techncal text on the engineering of food and other manufacturing processes is in the choice of units for he various physical properties of substances and process parameters involved. Much existing information is expressed in so-called engineering units (foot-pound-hour system), especially in the USA; and movement to full use of the metric system (centimetre-gram-second system) has been generally slow in English-speaking countries, except in reporting results of laboratory experimentation. Furthermore, we are now being encouraged to move further, to the adoption of the SI system (Systeme Internationale) of unit (metre-kilogram-second), which is the most logical of all. In this volume, the metric system is used as the basis, including for operations on the industrial scale, though simultaneous conversion is made back to engineering units where information arose in the system originally. Reference is also made to the corresponding SI units where it is thought to be appropriate, and the important relationships between the various relevant units used at different times are set out in the Appendix. A similar problem arises in the choice of symbols for physical properties and parameters; though a common system is developing, in discussion of the work of certain authors, this volume also uses the particular symbols as used originally. (Coffee Technology)

Each chapter has been written by an international expert in that particular field. It is therefore to be hoped that the present volume will provide a convenient and readable source of information and reference in the English language for all those interested in the industrial processing of coffee, and in the remaining but important process left to the consumer, i.e. coffee brewing

R.J Clarke

R. Macrae


Table of contents

Chapter 1 – Green Coffee Processing (J-C Vincent)

Chapter 2 – Grading, storage, pre-treatments and blending (R.J Clarke)

Chapter 3 – Decaffeination of coffee (S.N. Katz)

Chapter 4 – Roasting and Grinding (R.J Clarke)

Chapter 5 – Extraction (R.J Clarke)

Chapter 6 – Drying (R.J Clarke)

Chapter 7 – Packing of roast and instant coffee (R.J Clarke)

Chapter 8 – Home and catering brewing of coffee (G. Pictet)

Chapter 9 – Waste products (M.R. Adam and J. Dougan)

Appendix

 

 

 

 

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