Short- and long-term efficiency of carboxymethylcellulose (CMC) to prevent crystal formation in South African wine

Abstract

Crystal formation in bottled wine occurs due to the over-saturation of wine with potassium bitartrate (KHT) salt when exposed to low temperatures. In this study, special focus was given to the efficiency of a crystallisation-inhibiting additive, carboxymethylcellulose (CMC), which is widely used in the food industry. In 2008, CMC was authorised by the International Organisation of Vine and Wine (OIV) for use in white and sparkling wines, but is not yet officially permitted in all wine-producing countries. The use of CMC could be of economical importance to the wine industry because energy costs due to cooling can be reduced. Unlike traditional cooling methods, the use of CMC theoretically prevents the loss of acidity. In this study, the short- and long-term efficiencies of CMC were investigated in South African white, rosé and red wines. Efficiency was determined primarily by measuring changes in potassium (K⁺) and tartaric acid (H₂T) concentrations and visual crystal formation. As part of this study CMC's efficiency was compared with several other crystal inhibition treatments, and was also evaluated for its temperature stability over a year. CMC's effect on colour and total phenols was also assessed. The results reveal a high efficiency in preventing losses in K⁺ and H₂T concentrations in white wines, even with an ageing period of up to 12 months. The addition of CMC to rosé wines also delivered certain positive results, but less so for red wine. Three different commercial CMCs were also compared with mannoproteins to prevent changes in K⁺ and H₂T concentrations in three different wines. Furthermore, sensory evaluation was performed to determine certain organoleptic changes as a result of CMC treatments.

Keywords:

• quality assurance
• sensory
• additives general
• wine

Acknowledgements

The authors wish to thank the following people and organisations for their contribution to this project: Marinda Visagie, Marisa Nell and VinLAB Stellenbosch for analytical work; Enartis Laffort, CDS Vintec, IOC, for supplying the CMC and mannoproteins; Vrede and Lust, De Grendel Bottelary, Neethlingshof, Simonsig, KWV, Distell and Beyerskloof for supplying grapes/wine; and The Pinotage Association, Thrip and Institut Oenologique de Champagne for funding.