Rheological and Microbiological Characteristics of Hops and Hot Trub Particles Formed during Beer Production

Abstract

During the production of beer, and especially beer wort, the main wastes are spent grain and hot trub, i.e., the so-called “hot break.” Combined with yeast after fermentation, they represent the most valuable wastes. Hot trub is also one of the most valuable by-products. Studies on the chemical composition of these sediments and their rheological properties as waste products will contribute to their effective disposal and even further use as valuable pharmaceutical and cosmetic raw materials. So far, hot trub has been studied for morphology and particle distribution depending on the raw material composition and beer wort extract. However, there are no preliminary studies on the rheological properties of hot trub and hops. In particular, no attention has yet been paid to the dependence of these properties on the hop variety or different protein sources used. The aim of this study was to examine the effect of different hopping methods on hot trub viscosity and beer wort physicochemical parameters. Additionally, the hop solutions were measured at different temperatures. A microbiological analysis of hop sediments was also performed to determine the post-process survival of selected microorganisms in these wastes. For manufacturers of pumps used in the brewing industry, the most convenient material is that of the lowest viscosity. Low viscosity hot trub can be removed at lower velocities, which reduces costs and simplifies washing and transport. The sediments also had similar equilibrium viscosity values at high shear rates.

Rheological Properties of Industrial Hot Trub

“…Sterczyńska et al (2021) [ 49 ] provided data from preliminary studies of sediment obtained on a semi-technical scale in laboratory conditions. Those studies focused on the influence of different malts and hopping times on the value of apparent viscosity.…”

Physical Model for the Sustainable Transformation of Human Waste into Biogas in Housing

“…The digestate, which is the material residual after the digestion procedure, could be sold and used as fertiliser and manure in farms, thereby decreasing the requirement for chemical stimulants such as fertilizers. Also, it offers extra income when requested by farmers and sold as soil amendments and livestock bedding [27].…”

“…The breakdown of manure with diverse substrates yields higher energy output and biogas production. This might result in making biogas plants increase economic value by supporting economic recovery and job creation, decreasing people's helplessness towards energy prices, reducing greenhouse gases, and improving fertiliser value [27].…”

Current strategies for the management of valuable compounds from hops waste for a circular economy

“…The longer boiling precipitated sediment was found to be the most convenient material for the brewing industry because of its low viscosity which makes the composting process cheaper and easier. Hop sediments weren’t microbiologically contaminated and remained sterile so they could be further used ( Sterczyńska et al, 2021 ).…”