The Application Potential of Hop Sediments from Beer Production for Composting

Michał Kopeć,Katarzyna Wolny-Koładka,Monika Mierzwa-Hersztek,Krzysztof Gondek,Marek Zdaniewicz,Aleksandra Suder

doi:10.3390/su13116409

Michał Kopeć, Katarzyna Wolny-Koładka + Show 4 more

Open Access

https://doi.org/10.3390/su13116409

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Journal: Sustainability	Publication Date: Jun 4, 2021
Citations: 6	License type: CC BY 4.0

Affiliation: University of Agriculture in Krakow

Abstract

The chemical composition of hop sediments from beer brewing and fermentation gives them the potential for further use. These wastes are not generated in large amounts, but the absence of proper characteristics may lead to processing errors. This study examines the possibility of using hop waste for aerobic biological transformation processes (composting). The study was carried out on two hop sediments from two different technological stages of beer production: hot trub and spent hops. Chemical, microbiological, and biochemical analyses were performed in the composted hop sediments, as was the assessment of phytotoxicity to Lepidium sativum L. The tested feedstocks were partially inhabited by microorganisms and thus safe from an epidemiological point of view, and they were not a source of microbial contamination. Inhibitory properties for plant development were found for hot trub, which most likely result from the organic compound content. If it is only a small portion of its biomass, the mineral composition of hot trub does not exclude the possibility of its composting. Spent hops were characterized by a significant total nitrogen content, which affected the composting process. Composting this sediment required the selection of substrates with a widely C:N ratio.

Highlights

Beer production generates at least two types of solid waste associated with the hops used
A characteristic feature of the hot trub was a higher value of electric conductivity
The content of the tested elements in the hot trub was generally smaller or at a similar level to the content determined in the spent hops (SH)

Summary

Introduction

Beer production generates at least two types of solid waste associated with the hops used. These are hot trub and spent hops resulting from dry hopping [1,2,3,4,5]. Filtration sediments are considered to be the largest source of waste in a brewery (17.6 kg·hL−1 ), as on average they amount to 7% of the brewer’s grain mass [6]. Streczyńska et al [5] state that the value of solid wastes generated by 1 m3 of a finished beer product is much smaller than that reported a decade ago, and is equal to

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