Bioscience for sustainable agriculture and food

Bioscience for renewable resources and clean growth

Category: Standard Studentships

Managing malic acid and phenolic compounds in grape juice and wine using non-chemical viticultural and oenological techniques.

Project No. 2435


Primary Supervisor

Dr Belinda Kemp- NIAB East Malling


Prof Vladimir Jiranek – University of Southampton


Grape components such as polyphenols and organic acids are related to grapevine environmental changes, vineyard practises, and winemaking interventions.

Management of organic acids and grape phenolics, specifically stilbenes that inhibit malolactic fermentation, is needed in the UK to ensure sustainable, high-quality wines. This project will investigate non-chemical methods to reduce malic acid and manage grape phenolics in white and red wines.

A two-pronged approach will be used to identify organisms that could help tailor grape juice/wine composition. The student will initially conduct a detailed review of literature to highlight candidate strains based on their possession of the desired juice/wine modifying abilities. In addition, we have access to a large collection of yeast and bacteria via the University of Adelaide and, high-throughput screening capabilities to identify promising strains. The impact of the candidate strain will be assessed by wine chemical composition and sensory analysis. It is likely strains will then need to be applied as a co-culture with a standard wine yeast, as is the common industry practice. The studentship involves manipulating grape composition to manage malic acid and phenolics to achieve favourable concentrations for wines in a sustainable manner.
Project aims:

The aims of this project are twofold:
1. To evaluate viticultural non-chemical approaches to reduce malic acid levels in grapes.
2. To determine the impact of non-chemical viticultural and oenological intervention on wine phenolics, and malolactic fermentation kinetics.
A background in microbiology, chemistry and knowledge of fruit chemical composition would be an advantage. Training will be provided, and an interest in viticulture and oenology is a key criterion.