Authors: Juerg Baggenstoss Rainer Perren Felix Escher
Publish Date: 2008/03/18
Volume: 227, Issue: 5, Pages: 1357-1365
Abstract
Normal and long time roasting trials were carried out on industrial scale Different amounts of water were applied during quenching resulting in water contents in the range of 23–88 g/100 g wb Coffees were ground immediately after cooling and after equilibration times of 6 and 24 h Particle size distribution of ground coffees percolation time and extraction properties were investigated on an espresso coffee machine Coffees ground after 24 h resting time were subjected to storage trials to determine aroma stability as influenced by water content Coffees with high moisture content exhibited coarser particles upon grinding and equilibration time prior to grinding was needed for coffees with high water content to improve grinding results Coffees with low water content did not exhibit this time dependency prior to grinding Coffees with low water content were extracted more effectively than high moisture coffees and percolation was slower During open and closed storage evolution of hexanal and sulfides was highly sensitive to water content However differences in evolution of other aroma compounds were found during closed storage only where moisture content had a negative impact on aroma stability of the coffees subjected to investigationWe gratefully acknowledge the funding of this work by GW BARTH Ltd Freiberg Germany We thank Nestlé PTC Orbe Switzerland for assistance in aroma analysis and Delica AG Birsfelden Switzerland for supplying green coffee offering access to roasting and grinding equipment particle size analyses and determination of percolation times
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