Storage technologies of picked hops during harvest

摘要

To prevent interrupting the process of drying or picking due to lack or surplus of hops coming out of picking line, in most cases there is placed a storage container as a capacity equipment. In a container, however, hops are layered, thus temperature and relative humidity increase owing to an increased intensity of hop cones breathing and an insufficient airing, i.e. they mowburn. In the process of breathing a cone loses important substances which results in its worse quality and correspondingly in worse quality of the final product. This work builds on research from 2011. There were monitored changes of physical characteristic of picked hops during storage in container and compared with control variant. This aim of this work is to compare different storage technologies of picked hop in the container. There was a three variants. The control variant was a common stack with a perforated bottom. The second variant was a stack with active ventilation by electric fan. The third variant was a covered stack with passive air circulation. Al stacks had one cubic volume. Data of temperature and relative humidity were continually recorded by MINIKIN TH measuring equipment by EMS Brno company. Another analogue sensors to measure relative humidity and temperature were independently installed for check. The monitoring was each time carried out for 24 hours. Next there were collected a samples for laboratory analysis for product quality. During storage both the temperature and relative humidity of the control variant increased substantially, with temperature values reaching up to 41°C and relative humidity values 100%. The progress of temperatures was almost identical with all the measurements, that is why we present only the average values. The relative humidity of active ventilated variant increased up to 100% but temperature only up to 15°C. The values of humidity of passive ventilated variant were the same (100%) but values of temperature were lower instead of control variant. The highest measured temperature was about 22°C. The conclusion we may draw here says that the best way is passive air circulation. The lowest temperature was measured at variant with fan and it is most important for storage quality of hops but this variant is more expensive due to electric power.