South Africa Wine Technical Yearbook 2025

KINETICS OF CALCIUM DOSAGE BW WHITE WINE AFTER ADDITION OF CAFINISH™ WITHOUT STIRRING

AB™

180

156

160

50 g/hL 75 g/hL 100 g/hL 0 g/hL 200 g/hL

156

20 g/hL 30 g/hL 40 g/hL 50 g/hL 0 g/hL 60 g/hL

140

120

100

91 85 78 72

80

60

40

Calcium (mg/L)

20

0

0

5

10

15

20

25

30

Days

FIGURE 2. Calcium concentrations in white wine after the addition of different dosages of CaFinish. Figure 2: Calcium concentrations in white wine after the addition of different dosages of CaFinish™ Calcium concentrations in white wine after the addition of different dosages of CaFinish™

ddition

The recommended formula is: Dose (g/hL) = (Ca_initial - Ca_final) x 4

from climate change can lead to higher calcium levels in grapes. Consider optimising irrigation, cover crops and soil organic matter to maintain balanced vine nutrition. 2. Limit winemaking calcium inputs by avoiding or carefully controlling products such as calcium carbonate, low-purity casein and inferior-quality calcium-based bentonites, and by verifying the condition of cement tanks. 3. Maintain pH and acidity balance using biological tools, such as yeast or bacteria that produce or preserve organic acids like malic and citric acid, to reduce free tartrate ions that bind with calcium. 4. Preserve protective colloids by avoiding aggressive filtration, and note that common tartrate stabilisers (CMC, KPA and mannoproteins) are ineffective against CaT instability. 5. Actively remove excess calcium with targeted treatments: use Ca² + Stab in fermenting must or CaFinish in finished wine, applying the correct dose based on calcium analysis. Final words With continued research and practical solutions from suppliers, winemakers are better equipped to manage this challenge effectively.  * Dr Sami Yammine holds a PhD in Oenology from the University of Bordeaux. He is currently the Fining and Stabilisation Range Manager at LAFFORT ® .

This ensures effective treatment without overdosing. It is recommended to check the final calcium concentration to confirm the treatment’s completion. On the other hand, CaFinish works by following the wine’s natural instability curve. Q: Does LAFFORT® offer any biological solutions to help alleviate the situation? A: Yes, indeed. • ZYMAFLORE™ KLIMA (Saccharomyces cerevisiae) produces malic acid during fermentation that can act as an inhibitor to CaT crystal formation. Additionally, it has a lower alcohol yield than most wine yeast strains, further reducing the chances of instability. • ZYMAFLORE™ OMEGA (Lachancea thermotolerans) produces lactic acid from glucose, leading to a natural acidification of wine, reducing the need to add exogenous tartaric acid to juice or wine. • LACTOENOS™ BERRY Direct (Oenococcus oeni) preserves the citric acid content of wines during malolactic fermentation, which can act as an inhibitor to CaT crystal formation. Q: What are the top five tips to prevent CaT instability in wine? A: 1. Manage hydric stress in the vineyard, as drought and heat

S TO HELP ALLEVIATE THE SITUATION?

uces malic acid during fermentation that can act as an inhibitor to CaT crystal formation. roduces lactic acid from glucose, leading to a natural acidification of wine, reducing the

ves the citric acid content of wines during malolactic fermentation, which can act as an

For more information, contact Morné Kemp at morne.kemp@laffort.com. Reference https://www.wineland.co.za/qa-tackling-calcium-crystals-in-wine/

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TECHNICAL YEARBOOK 2025