Document Type
Doctoral Thesis
Disciplines
*Wine and Beverage Studies
Abstract
The Irish brewing and distilling sector has shown a consistent increase in number, production output, sales, and export value in the last decade. This has implications for raw materials requirements, assessment, and by-products management for the sustainability of the sector. As a result, the main aim of this research study was to evaluate the status of raw materials use and assessment within the Irish brewing and distilling sector, explore by-products management options and valorisation initiatives, and analyse the environmental impact of Irish whiskey production. The first approach was a survey study to collect data on major raw material inputs use and trends in by-product management and sustainability practices. This was followed up with a quality assessment of wastewater from the sector. After a scoping review of the current state of the art in the valorisation of brewing and distilling by-products, spent gin botanical was identified for sampling and analysis to explore it for added value use. The mineral profile, phenolics content, antioxidant activity, phenolics profile, and biological activity of the spent gin botanical samples were evaluated using standard assay protocols, ICP-MS, and LC-MS techniques. Life cycle assessment of single malt Irish whiskey was carried out using ISO 14044 LCA methodology. The survey study received responses from 23 breweries and 17 distilleries in Ireland. Notable trends from the survey data included utilisation of the by-products of spent grain and pot ale mostly in animal feed, and energy and packaging initiatives being the leading sustainability initiative. The results from the analysis of spent gin botanical samples showed that the mineral profile of the samples included K, Ca, Mg, Na, Fe, Cu, Mn, and Zn. The macro minerals, K and Ca were the most abundant and ranged from 475 to 611 mg/100 g and 476 to 555 mg/100 g, respectively. While for the trace minerals, Fe was the most abundant and ranged from 6.87 to 12.15 mg/100 g. Optimised values for polyphenol extraction from the samples were ethanol concentration of 50%, 40 mL g-1 solvent: sample ratio, and temperature of 65 oC. This gave a total phenolic content of 13.14 mg GAE/g, total flavonoids content of 27.75 mg QE/g, total antioxidant capacity of 10.69 mg AAE/g, DPPH radical scavenging activity of 8.10 mg AAE/g and ferric reducing antioxidant power of 7.76 mg TE/g. The samples retained up to 50% of their phenolic content and antioxidant capacity post-distillation. The LC-ESIQTOF/MS analysis identified and verified 60 polyphenols in the samples which included phenolic acids, different groups of flavonoids, lignans, stilbenes, and other uncategorised groups of polyphenols. The bioactivity assays indicated that the by-product had some level of biological activity for the inhibition of ACE1 (21.3 – 23.9%) and AChE (34.8 – 36.7%). The economic importance of polyphenols highlighted the possible market value of the by-product and its potential for added value use in mineral supplementation and fortification, product development, functional foods, clean label initiatives, and cosmetics. LCA of single malt Irish whiskey showed that global warming, acidification, and eutrophication potentials were 2.26 kg CO2 eq., 0.013 kg SO2 eq., and 0.015 kg PO4 eq. per litre of pure alcohol, respectively. Identified hotspots from the assessment were energy use (gas and electricity) and barley cultivation. This study gave an insight into the status of raw materials use within the Irish brewing and distilling sector. It identified opportunities in sustainable by-products management using spent gin botanicals as a reference point. These insights and valorisation options can be used to drive sustainability within the sector. The life cycle assessment study can form the basis for environmental impact monitoring and control for Irish beer and spirit products.
DOI
https://doi.org/10.21427/j4xx-p710
Recommended Citation
Umego, Ekene C., "Capacity Building in the Irish Brewing and Distilling Sector for Raw Materials Utilisation, By-products Management, and Environmental Impact Assessment" (2025). Doctoral. 287.
https://arrow.tudublin.ie/sciendoc/287
Creative Commons License
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Publication Details
A thesis submitted to Technological University Dublin in fulfilment of the requirements for a PhD degree, School of Food Science and Environmental Health, City Campus, Technological University Dublin, 2025.