The mechanism of precipitation of calcium L(+)-tartrate in a model wine solution

The influence of wine polymers on the spontaneous precipitation of calcium tartrate in a model wine solution

“…The model wine system used in this study has been described in detail elsewhere (McKinnon et al ., , ). In summary, a solution containing tartaric acid and the relevant wine polysaccharide were added with efficient stirring to a calcium solution maintained at 15 °C.…”

“…The influence of wine components on the spontaneous precipitation process of calcium tartrate has been examined, and it has been observed that wine organic acids, and specifically malic and citric acids, are effective inhibitors of the calcium tartrate precipitation process (McKinnon et al ., ). Lactic acid is also an inhibitor, but it is not as effective as malic acid.…”

“…Succinic acid, on the other hand, has no effect on the induction process for the precipitation of calcium tartrate. Extending this study to examine the influence of a wide range of wine components, it was concluded that wine organic acids with a carboxyl or hydroxyl group adjacent to the acid group were the most efficient inhibitors of the spontaneous precipitation process (McKinnon et al ., ).…”

“Enological” Metal Speciation Analysis

“…As a result of the reductive medium, metal ions in wines are in a low oxidation state; on the other hand, the number of their potential complexes is fairly large for there is a scale of complex-forming substance (1,3,4). Unfortunately, there is a lack of sufficient information on the stability of the complexes on the pH of the wine in the solution of water and alcohol; neither are standards available.…”

“…Enologically this colloidal fraction is very important, because it destroys the quality of wines. The application of smaller-pore-size filters makes further differentiation between molecules according to their molecular weight possible (3,4). After filtration, the metal contents of different liquid fractions can be determined (5).…”