Alana will be speaking in Session 9. Fresh Science B. Click here to see more.
Insufficient acidity in grapes from warm climates is commonly corrected through addition of tartaric acid during winemaking. An alternative approach involves bio-acidification with Lachancea thermotolerans (LT) via lactic acid production during fermentation. Our work elucidated the genetic (~200) and phenotypic (~100) diversity of LT strains, whilst delivering a starter capable of lowering wine pH by ~0.5 units when used in co-cultures with Saccharomyces cerevisiae (SC). Here, we i) compared the profiles of bio-acidified LT wines and acid-adjusted SC wines, and ii) evaluated the use of LT wines as blending components. High sugar/pH Merlot was fermented with a sequential culture of LT/SC, or an SC monoculture. The aliquots of the SC control (pH 4) were acidified with either tartaric or lactic acid to the pH of the LT wine (pH 3.6), and the initial wines also blended in three proportions (1:3, 1:1, 3:1). Chemical analysis revealed major differences in a range of chemical parameters of wines, which were largely reflected in their ‘Rate-All-That-Apply’ sensory profiles. Sensory profiles of the bio-acidified LT wine and the lactic acid-adjusted SC wine were similar, and contrasting to the tartaric acid-adjusted SC wine. Lactic acid-adjusted wine had higher ‘red fruit’ flavour, and lower ‘hotness’, ‘bitterness’ and ‘jamminess’ relative to the tartaric acid-adjusted. This was driven by differences in ‘acidity’ perception, affected by TA (rather than pH) of wines. The profiles of blends were modulated depending on the proportion of the bio-acidified wine, thus highlighting the potential of this approach to fine-tune ‘freshness’ and differentiate wine styles.
Dr Alana Seabrook has worked in the wine industry for the past 20 years in winemaking, wine research and application, wine microbiology, diagnostics and laboratory. After completing a winemaking degree through the university of Verona, Italy, she completed a PhD in wine microbiology at the University of Adelaide and went on to work in industry as Microbiologist and then R&D manager in an industry setting. Alana has been working as the technical manager for Laffort Australia since 2017 as well as managing technical communications for the Winechek laboratories group from January 2022. In her role at Laffort she supports a national sales team and works with wineries all around Australia to optimise their processes as well the application of novel and existing research into production. Alana is an active member in the Australian society for Viticulture and Oenology and a current South Australian ASVO and AWITC director.