Understanding the drivers of quality and consistency in cider production
Creators: name: Way, Madeleine
Publisher: name: University of Tasmania
Year: 2024

description: Apple cider is a popular alcoholic beverage created by fermenting apple juice. The Australian apple cider industry is relatively young compared to other countries such as France, Spain and the UK, and other beverage industries such as wine. Despite many of the factors influencing quality remaining unclear, cider producers using fresh locally sourced apple juice or fruit instead, of concentrate, aim for a consistent high quality product. This thesis is an exploration of factors influencing cider quality and the ways in which quality indicators can be measured including base cider chemistry parameters and sensory analysis. Key knowledge gaps for cider producers addressed in this research were how apple variety, yeast strain and growing region influence cider quality.<br>Key base cider chemistry parameters include pH, total soluble solids (TSS), titratable acidity (TA) and total phenolic content (TPC), all of which can be linked to organoleptic qualities such as colour, aroma, flavour and mouthfeel. Traditionally the Folin-Ciocalteu method has been used to determine TPC in cider, however it is time consuming, expensive and found to be influenced by compounds other than phenolics. The Somers method, a spectrophotometric method developed specifically for wine, offered a new method to measure cider TPC in a rapid and affordable manner but was yet to be validated for use on apple cider. Phenolic analysis was conducted on apple juice and base cider, made from six apple varieties including dessert and cider apples, using three different analytical methods to enable comparison: (a) the Folin-Ciocalteu method, (b) the Somers method, and (c) ultra-performance liquid chromatography (UPLC) as a benchmark test. The Somers method had the strongest correlation with UPLC with an R<sup>2</sup> value of 0.99, whilst the Folin-Ciocalteu correlated with UPLC with an R<sup>2</sup> value of 0.89. The Folin-Ciocalteu method also had a strong positive correlation with the Somers method with an R<sup>2</sup> value of 0.91. These results highlight the potential of the Somers method to rapidly, inexpensively, and accurately report the TPC of apple juice and ciders made from dessert and cider apple varieties. For this reason, TPC was measured using the Somers method for the remainder of experimental chapters.<br>Fermentation involves complex biosynthetic pathways between yeast and apple juice which produce a range of compounds responsible for the organoleptic qualities of cider. Due to the large number of yeast strains and apple varieties commercially available for cider fermentation in Australia, research was required to better understand the influence of yeast strain on key cider characteristics and consumer perception in the context of a range of apple varieties. The third chapter of this thesis evaluates different yeast strains and the resulting impact on quality through measuring base cider chemistry parameters as well as performing descriptive sensory analysis. Ciders were made from single variety micro ferments using three commonly available apple varieties (‘Pink Lady’, ‘Sturmer’,and ‘Bulmer’s Norman’) and inoculated using six single yeast strains, while also including a wild ferment. Although season and variety dependent, results revealed that yeast strain can influence the pH, TA, and TPC of apple cider. Using a trained panel, descriptive sensory analysis was conducted on cider made from ‘Pink Lady’ apples and the same six yeast strains and the wild ferment. The sensory panel significantly differentiated ciders made from different yeast strains on the attributes of, ‘fresh apple’, ‘earthy’ and ‘pear’.<br>Beverage marketing campaigns often focus on place-based branding and regionality. The French term terroir describes the link between sensory attributes and geographically specific conditions. This is often a combination of interactions between climate, geology, variety, and management practices, which create a unique environment to produce distinctive characteristics, influencing the sensory attributes of a product. Although terroir is commonly considered in the context of wine, it could be applied to cider. Understanding the links between desired flavour characteristics and specific varieties grown in certain conditions, has the potential to improve the cider category in Australia. As a result, a study was designed to test if the region in which apples were grown influenced the final cider quality when made using consistent techniques, avoiding confounding variables that could occur from commercially purchased samples.<br>Ciders were made from ‘Fuji’ apples sourced from three major apple growing regions in Australia, Stanthorpe (QLD), Batlow (NSW) and the Huon Valley (TAS). Descriptive sensory analysis was performed by a trained panel by ranking the intensity of pre-determined attributes across the ciders. Sensory attributes were found to vary significantly between regions. Cider made from apples grown in Stanthorpe was ranked significantly higher than ciders made from apples sourced from Batlow and Huon Valley for the attribute ‘alcoholic’. Cider made with apples from Batlow was ranked significantly higher for the attribute ‘yeasty’ compared to cider made using apples from the Huon Valley. Cider made with apples from Stanthorpe had significantly greater TPC, TA, TSS and alcohol by volume than the two other locations. The concept of terroir could be applied to apple cider as ciders were differentiated by sensory analysis based on the geographical region from where the apples were grown, displaying the influence of region on quality.<br>In the final study, the influence of growing region was investigated over two growing seasons, from nine major growing regions and across three different dessert varieties. Climate conditions including Growing Degree Days and average rainfall were also modelled against quality measures to determine potential drivers of quality. Evidence of regional differences in pH, TA, TSS and TPC was found across both seasons. Variety, region and season, was found to influence cider quality measurements.<br>