Anne Elizabeth Hill

Brewing water must meet potability standards, as its chemical composition directly affects beer quality and process consistency. Understanding spatial and temporal variability in water composition is essential for quality control and risk management in brewing. This study evaluated the spatiotemporal variation of six key brewing parameters (pH, calcium, magnesium, sodium, chloride, and sulphate) in the Basque Country (Spain) from 2019 to 2023. A comprehensive dataset of drinking water analyses from multiple municipalities was assessed using spatiotemporal analysis tools to identify trends, variability patterns, and potential deviations from recommended brewing water ranges. Water composition showed notable spatial variability, while temporal fluctuations were generally limited. Most parameters remained within recommended ranges for brewing. However, isolated exceedances were identified for sulphate (two municipalities) and sodium (one municipality), representing less than 0.06% of the total records. These deviations may affect flavor profiles and process stability if not properly managed. The findings highlight the importance of continuous monitoring of source water to ensure consistent brewing quality, despite limitations associated with heterogeneous monitoring practices and multi-year data aggregation. The proposed spatiotemporal approach supports risk-based decision-making for brewery location, contributing to improved quality control in the brewing industry.

Why was the work done: The Scotch whisky industry is committed to cutting carbon emissions to net zero by 2040. A consistent and accurate measurement of carbon emissions across the industry would enable distillers and their stakeholders to make informed decisions on sustainability. Accordingly, this work presents a user friendly carbon footprint calculator. How was the work done: Focusing on single malt Scotch whisky, the study defined the scope of the calculator and applied UK government carbon accounting methods. A web-based calculator was developed (https://www.ai4whisky.com) and evaluated using data from a simulated distillery producing 3,000 litres of pure alcohol (LPA) in a batch process. What are the main findings: The calculator considers the distillery, maturation warehouse and bottling hall, accounting for raw materials and their transportation, energy consumption, product transportation and waste disposal within each facility. The case study calculated a carbon footprint of 2.83 kg CO₂e per 70 cL bottle of whisky. Scope 1, 2, and 3 emissions accounted for respectively, 15, 8, and 77% of the total. The calculator also visualised emissions by facility and highlighted key contributors to the overall footprint. Why is the work important: The work addresses the challenges of achieving a consistent and accurate carbon footprint for whisky products. The calculator can be adopted by distillers, especially those without access to bespoke carbon accounting tools, or with limited data on the specific footprint of their supply chain. Furthermore, it can pave the way for a global standard method for carbon accounting in the Scotch whisky industry and for other distilled spirits.

Why was the work done: Juniper berries and other plant botanicals are used in the production of beverages and contribute signature flavour and aroma. Inconsistent or inferior quality of botanicals is a concern and result in consumer dissatisfaction, and reduced sales. How was the work done: The impact on gin quality of the source and harvest year of juniper berries was investigated by analysis of distillates using Gas Chromatography - Mass Spectroscopy with Solid Phase Micro Extraction (GCMS-SPME). What are the main findings: Regional variation and drying regimes were found to impact on the concentration of volatiles and their profile. The least soluble compounds were most affected by post-harvest drying and increased in abundance whereas the more soluble compounds decreased in abundance. Why is the work important: This work will be of interest to distillers, suppliers of botanicals and juniper farmers, and will inform drying regimes consequent on climate change.

High-gravity brewing is a method that maximises brewhouse capacity and reduces energy consumption per unit of beer produced. The fermentation of wort with high sugar content is known to impact the fermentation characteristics and production of aroma-active volatiles, and as such, cultures that are adapted to this method are industrially valuable. Mixed-culture fermentation offers brewers the opportunity to combine desirable features from multiple strains of yeast and to take advantage of the interactions between those strains. In this study, a highly attenuative strain of Schizosaccharomyces pombe is paired with a fast-fermenting brewing strain of Saccharomyces cerevisiae in the fermentation of wort at both standard and high gravity at centilitre scale. Mixed cultures were found to produce several esters and higher alcohols in higher concentration than in either of the parent monocultures at both standard and high gravity. The mixed culture also represented a compromise between fermentation length (modelled by the logistic equation), which was extended by the inclusion of S. pombe, and ethanol yield, which was increased. The application of mixed-culture strategies to high-gravity brewing practices may allow brewers greater flexibility in achieving desired flavour profiles whilst increasing brewhouse efficiency.

Flavour in Scotch malt whisky is a key differentiating factor for consumers and producers alike. Yeast (commonly Saccharomyces cerevisiae) metabolites produce a significant amount of this flavour as part of distillery fermentations, as well as ethanol and carbon dioxide. Whilst yeast strains contribute flavour, there is limited information on the relationship between yeast strain and observed flavour profile. In this work, the impact of yeast strain on the aroma profile of new make spirit (freshly distilled, unmatured spirit) was investigated using 24 commercially available active dried yeast strains. The contribution of alcoholic, fruity, sulfury and sweet notes to new make spirit by yeast was confirmed. Generally, distilling strains could be distinguished from brewing and wine strains based on aroma and ester concentrations. However, no statistically significant differences between individual yeast strains could be perceived in the intensity of seven aroma categories typically associated with whisky. Overall, from the yeast strains assessed, it was found that new make spirit produced using yeast strains marketed as ‘brewing’ strains was preferred in terms of acceptability rating.