Evaluating the effectiveness of alginic acid, sodium carboxymethylcellulose, and potassium polyaspartate in preventing calcium tartrate instability in wines

Abstract

Calcium-induced instabilities present a major challenge in bottled wines, with calcium tartrate (CaT) precipitation becoming increasingly common due to rising calcium levels in grape must, largely driven by climate change. Although CaT is an insoluble salt, its instability— although less frequent than potassium hydrogen tartrate (KHT) precipitation—is more difficult to predict and control, as it develops gradually over time [1]. Spontaneous nucleation of CaT takes significantly longer than that of KHT, resulting in delayed precipitation, often occurring years after aging and typically post-bottling [2,3]. CaT instability occurs when ion concentrations exceed the solubility threshold, resulting in crystal formation. Unlike KHT, CaT precipitation is minimally affected by temperature, making cold stabilization ineffective [4]. Various additives, such as metatartaric acid and carboxymethylcellulose (CMC), have been used to mitigate this problem. However, the long-term effectiveness of metatartaric acid is limited due to hydrolysis [5]. In addition, potassium polyaspartate (KPA), commonly used as a KHT stabilizer, has been suggested to potentially reduce CaT stability in some cases. Given the need for effective and sustainable stabilization methods, research into alternative tartrate stabilizers is essential. Alginic acid, an approved processing aid in winemaking, represents a promising alternative to CMC and metatartaric acid due to its strong negative charge and ability to bind calcium ions. Already approved by the OIV [5], for wine clarification with no restrictions on use, alginic acid represents a clean-label solution for CaT stabilization. This study aim to evaluate the efficacy of alginic acid as a CaT stabilizer compared to CMC and to assess the effect of KPA on CaT instability. The stability of CaT was evaluated using the method described by Abguéguen and Boulton [1]. The degree of CaT instability in wine was determined according to Triulzi et al. [6] based on the decrease in calcium concentration after the addition of micronized calcium tartrate. The results showed that KPA did not increase CaT instability and, in some cases, even enhanced stability. Alginic acid demonstrated superior performance over both CMC and KPA, likely due to its higher zeta potential and stronger calcium ion complexation capacity. While these findings are highly promising, they primarily reflect short-term stabilization effects, highlighting the need for further long-term studies.

Funding

Project Vine&Wine Portugal—Driving Sustainable Growth Through Smart Innovation, Application No. C644866286 00000011, co-financed in the scope of the Mobilizing Agendas for Business Innovation, under Reg. (EU) 2021/241, in the Plano de Recuperação e Resiliência (PRR) to Portugal, na sua componente 5—Capitalização e Inovação Empresarial.

References

[1] Abguéguen, O., Boulton, R.B. (1993). Am. J. Enol. Vitic. 44, 65–75.

[2] Postel, W. (1983). Bull. OIV, 629–630, 554–568.

[3] Clark, J., Fugelsang, K., Gump, B. (1988). Am. J. Enol. Vitic., 39, 155–161

[4] Ribéreau-Gayon, P., Glories, Y., Maujean, A., Dubourdieu, D. (2006). Handbook of Enology. Volume 2. The Chemistry of Wine. Stabilization and Treatments, 2nd ed.; John Wiley & Sons Ltd Dunod: Paris, France.

[5] OIV. (2023). International Code of Oenological Practices; OIV: Paris, France.

[6] Triulzi, G.; Quinterno, G.; Scotti, B. (2021). Rev. Da Assoc. Port. De Enol. E Vitic., 69, 61–69.