South Africa Wine Research Projects 2025

3. OENOLOGY RESEARCH NEW PROJECT

CALCIUM TARTRATE INSTABILITY IN SOUTH AFRICAN WINES

SAGWRI WdT 25-01 Prof Wessel du Toit, South African Grape and Wine Research Institute, Stellenbosch University Start date: 2025

AIM AND INDUSTRY RELEVANCE: Recently, the South African wine industry, along with international sources, has reported a significant increase in calcium tartrate (CaT) instability in wines. The formation of CaT crystals is visually unappealing to consumers, highlighting the urgent need for effective prevention measures. While the factors influencing potassium hydrogen tartrate (KHT) formation in wine are better understood, there is limited information regarding those affecting CaT formation. Discussions with several wine producers and companies have proposed potential factors that play a role in solving this problem. However, many factors influencing CaT crystal formation in wine remain unknown. A common concern is that current tests for predicting CaT crystal formation need to be evaluated and adjusted to include South African wines, as the existing test procedures were developed using European wines. An in-depth literature search also revealed limited recent scientific publications on this issue. Consequently, this project aims to identify specific viticultural and winemaking factors that impact CaT crystal formation in South African wines. Additionally, it seeks to investigate the efficacy of current tests in predicting CaT formation under South African conditions.

SOUTH AFRICA WINE RESEARCH 2025

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