Enartis

The precipitation of calcium tartrate represents a new challenge that wine producers can now solve, simply and without changing the profile of their wines.

Calcium tartrate, which is easy to identify through observation under the microscope by the typical shape of the crystals, can be difficult to manage, due to the complexity of the factors that lead to its formation. It is common knowledge that in wine the solubility of CaT is ten times less than the solubility of KHT, and the concentration of calcium ion can vary between 40 and 150 mg / L. In addition, the process of forming this crystal is very slow and the decrease in temperature does not allow the process to be accelerated, as in the case of KHT.

Normally, calcium concentrations above 80 mg / L in white wines and 60 mg / L in red wines are considered to be at risk for the appearance of precipitates.
The calcium content alone is not sufficient for a correct assessment of the situation: it is also necessary to consider the pH and the concentration in tartaric acid. PH is the parameter that regulates the balance between tartaric acid (H2T), the bitartarate ion (HT-) and the tartrate ion (T2-): as it increases, the presence of the tartrate ion and the probability of formation of CaT increase as well. It is assumed that climate change is primarily responsible for the increase in the pH of wines.

Precipitation of calcium tartrate is becoming more frequent all over the world and causing both economic and brand damage that companies should be aware of. The cause of the problem is still unknown but may be found in climate change, viticultural and enological practices or the use of untreated concrete tanks. Whatever the origin, it is important to know how to identify wines that are potentially calcium unstable and how to treat them.