Physical characteristics of picked hops during storage
Czech University of Life Sciences Prague, Faculty of Engineering,Kamýcká 129, Praha 6 – Suchdol, Postcode 16521, Czech Republic;
To prevent interrupting the process of drying or picking due to lack or surplus ofhops coming out of the picking line, hops, in most cases are placed in a storage container.. In acontainer, however, hops are layered, thus temperature and humidity increase owing to anincreased intensity of hop cones breathing and an insufficient airing, i.e. they mowburn. In theprocess of breathing a cone loses important substances which results in its deteriorated qualityand correspondingly in the poor quality of the final product. Our task was to observe the courseof hop temperature and humidity in a storage container and to compare it with the checkvariant, which was loosely spread hops outside the container. Data of temperature and humiditywere continually recorded by COMET D 3631 measuring equipment with N1ATG8/Cmeasuring probe by the Comet System company. Other analogue sensors to measure humidityand temperature were independently installed for checking. The monitoring was each timecarried out for 24 hours. During storage both the temperature and humidity of the hops in thecontainer increased substantially, with temperature values reaching up to 49 °C and humidityvalues 100%. The progress of temperatures was almost identical with all the measurements, thatis why we present only the average values. The highest temperature inside the container was inthe range of 39 °C to 49 °C with individual measurements. The temperatures of the checksamples were identical with the air temperature in the daytime with all the repeats. Themaximum temperature of the check samples ranged from 21 °C to 27 °C with eachmeasurement. In the same way as with the temperature, during the individual measurements thehumidity showed similar progress and the measurements did not differ from each other in anysubstantial way. The humidity level in the container rose up to the maximum value of 100%already two hours after the measurement had started and stayed like this until the end. Thehumidity of the hop check samples was 2.24% higher than the air humidity, which might beexplained by water vapour emission due to an increased intensity of hop cones breathing. Theconclusion we may draw here says that with an increasing volume and, probably above all,height of the stored hops layer, the influence of the surroundings on the conditions inside thecontainer will decline.