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Fig. in which rotating horizontal bowl is used for intimate contact of hot gases and beans.Hot air blast assisted by centrifugal force carries the seeds to the periphery; they then fallback to the center. After short roasting time discharge occurs from the periphery of the bowl. Fluidized bed roasters are used for large-scale roasting of coffee beans. Both heating and cooling are achieved in the same vessel by uidized-solid contact technique. Fluid-ized roasters have better control of process parameters and deliver the product with uni-form roasting. The spouted bed roaster (Fig. is variant of the uidized bed roasterthat has an advantage in large-scale roasting and tends to develop unstable uidization.Pressure roasting is considered to be potentially more efcient and is generally consideredto increase the acidity of the brew. Nitrogen is used as the pressurizing agent (9, 2, . 4.1.2 Grinding After developing the coffee avor by roasting, efcient extraction of the roasted coffee solubles and volatiles that contribute to coffee avor and aroma is desirable. The solublescould be extracted from the whole roasted beans, but the yield would be low and avor Coffee Processing 7 Fig. 1 The Gothot Rapido-Nova standard-type batch roaster, showing xed roasting drum with paddles, furnace, and cooling car. (From Ref. 1. Reproduced with permission.) would be poor. Extraction may be made to give higher yield of solubles by breaking down the whole bean to smaller pieces. The roasted beans cannot be ground directly afterroasting as they are too soft and would be crushed, attened, and scarred. Therefore, water quenching is an essential step before grinding. When the beans are cooled, they become hard and brittle and can be ground. Various types of grinders are available for large-scalegrinding of coffee beans. The extraction and keeping quality of the coffee powder isinuenced by the size of the particle. There are three standards: regular grind, drip grind,and ne grind. Fine