Airflow resistance of two hop varieties
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Kuupäev
2021
Kättesaadav alates
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Ajakirja pealkiri
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Kirjastaja
Abstrakt
The quality of hops used in brewing is substantially reliant upon the processing step of
drying. To ensure effective drying in kiln as well conveyor-belt dryers, homogeneous distribution
of air is of particular importance. Uneven air distribution often results in inefficient drying and
nonuniform moisture content of the hop cones. The air distribution naturally is governed by the
airflow resistances in the individual floors or belts of a dryer. Hence, in order to quantify the
airflow resistance of hop cones at different air velocities and bed heights, systematic
measurements were carried out. In addition to determining the bulk densities of hops, the
investigations included trials with fresh and dried hop samples. Clear differences were observed
between hop varieties both in measured pressure drops and in bulk densities. Moreover, in the
case of fresh hops, a non-linear increase in pressure drop with bed height was ascertained. Semiempirical equations were developed to describe pressure drop as a function of air velocity. This
work will contribute to the design of dryers with optimum airflow distribution and thus enhance
the efficiency of drying as well as the product quality.
Kirjeldus
Received: December 21st, 2021 ; Accepted: February 13th, 2021 ; Published: February 16th, 2021 ; Correspondence: tziegler@atb-potsdam.de
Märksõnad
airflow resistance, bulk density, drying, hops, pressure drop, articles