South Africa Wine Technical Yearbook 2025

TABLE 1. Racemic tartaric acid versus calcium tartrate. Figures 1 and 2 demonstrate the difference in efficacy of the two products in removing in a stoichiometric and proportional manner. Therefore, dose calculation must be car recommended formula is: Racemic tartaric acid

Calcium tartrate Finished wines 50 - 100 g/hL

Optimal treatment Treatment dose (g/hL) Duration of treatment Treatment mechanism Treatment temperature Cost of treatments Risk in the case of excess Impact on acidification Maximum dose of use

Fermenting must

Dose = (Ca init - Ca fin ) x 4 Dose (g/hL) = (Ca_initial – Ca_final) × 4

6 weeks

2 - 4 weeks

Calcium insolubilisation No influence of temperature

Growth of calcium crystals

Lower than 12°C This ensures effective treatment without overdosing. It is recommended to check th completion. On the other hand, CaFinish™ works by following the wine’s natural instabi

Moderate

High

Yes

No

High

Weak

–

200 g/hL

KINETICS OF CALCIUM DOSAGE IN WHITE BW AFTER ADDITION OF CA 2+ STAB™

180

180

160

160

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

156

140

140

120

120

98

100

100

80

80

65 44 43 23

60

60

40

40

Calcium (mg/L)

Calcium (mg/L)

20

20

0

0

0

0

5

10

15

20

25

30

Days

FIGURE 1. Calcium concentrations in white wine after the addition of different dosages of Ca 2+ Stab. Figure 1: Calcium concentrations in white wine after the addition of different dosages of Ca 2+ Stab™ Calcium concentrations in white wine after the addition of different dosages of Ca 2+ Stab™

C

Figure

influenced by temperature. 6 That’s why CaT crystals often only become visible after bottling. Solubility of CaT and KHT is also greatly affected by the alcohol content of the wine – the higher the alcohol, the lower the solubility of these compounds. Q: Some wines with high calcium content don’t show instability. Why is that? A: Because wine contains inhibitory compounds that can slow or prevent crystallisation. 7 These include: • Citric and malic acid. • Polyphenols, proteins and polysaccharides (protective colloids). The removal of protective colloids with inadequate (or poor) filtration can also be the reason why instability occurs after bottling. Q: What are the main strategies to prevent CaT instability? A: Removing excess calcium is the most effective method. All these methods have advantages and disadvantages. Cellars must choose the method that works best in their environment. Additives like mannoproteins, carboxymethyl cellulose (CMC), or potassium polyaspartate (KPA), although useful for preventing KHT instability, have limited efficacy in preventing CaT instability. There is some emerging evidence that alginic acid, which is approved for use in sparkling wine only, may also have beneficial effects. 2 Q: What solutions does LAFFORT® offer to manage calcium concentrations in wine? A: LAFFORT ® offers two products: Ca² + Stab (racemic tartaric acid) and CaFinish (micronised calcium tartrate). The differences in their applications are demonstrated in Table 1. Figures 1 and 2 demonstrate the difference in efficacy of the two products in removing calcium. Ca² + Stab reduces calcium levels in must or wine in a stoichiometric and proportional manner. Therefore, dose calculation must be carefully considered to avoid excess product in the wine. D OES LAFFORT® OFFER ANY BIOLOGICAL SOLUTIONS TO HELP ALLEVIATE THE Yes, indeed. • ZYMAFLORE™ KLIMA ( Saccharomyces cerevisiae ) produces malic acid during ferme • ZYMAFLORE™ OMEGA LT ( Lachancea thermotolerans ) produces lactic acid from gluc need to add exogenous tartaric acid to juice or wine. • LACTOENOS™ BERRY Direct ( Oenococcus oeni ) preserves the citric acid content of inhibitor to CaT crystal formation. This can be done through: • Cation exchange resins. • Electrodialysis. • Racemic tartaric acid (DL form). • Micronised L-calcium tartrate.

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TECHNICAL YEARBOOK 2025