The Crystallization Kinetics of Calcium Tartrate From Model Solutions and Wines

¹ Department of Viticulture and Enology, University of California, Davis, CA 95616-8749, USA.

The crystallization kinetics of calcium tartrate were investigated in order to better describe and predict the rates and extent of this instability in wines. Purified samples of calcium tartrate had to be prepared by recrystallization and used for this work. The calcium and tartaric acid concentrations were measured using atomic absorption and HPLC respectively. The effects of seed level (4, 20, 30 g/L), temperature (5°C, 10°C, 15°C, 20°C), particle size (50, 200 µm), ion strength (108, 140, 330 mM/L), alcohol content (10%, 12%, 14% v/v), and malic acid (2, 4, 6 g/L) were investigated in model solutions. The corresponding overall crystal growth constants were determined for these cases. Four wines were also studied (Chardonnay, Cabernet Sauvignon, Pinot blanc, and Pinot noir) at temperatures of 4°C, 12°C, and 20°C. The activation energy for these growth rate constants varied threefold between the wines. The growth constant in wines was essentially independent of the malic acid or total phenol content. A rapid stability test for calcium tartrate was developed and tested.

Key words: calcium tartrate, crystallization

Submitted on April 1, 1992