Winemakers are increasingly observing the presence of calcium tartrates (CaT) in wines already bottled and therefore considered stable. These precipitations are due to the increase of calcium ions already in the grapes, as also shown by numerous monitoring conducted and by EVER in recent years.
If until a few years ago the instability of Calcium was limited to some wine-growing areas, today it extends to the entire wine world. The calcium threshold values in wine, above which the oenologist should worry about the onset of possible precipitates are: 60 mg / L for red wines and 80 mg / L for white and rosé wines.
These two references do not take into account some factors that can favor or, conversely, slow down and / or inhibit calcium instability; specifically, it refers to the colloidal structure, pH, alcohol content, total acidity and potassium concentration of the wine.
To reduce the concentration of Calcium in conventional wines, the Enologist knows the following subtractive techniques: Refrigeration, Dipotassium Tartrate in racemic form (e.g .: CRIO-PLUS – EVER), Calcium Tartrate and Cationic Resins (e.g .: STABTAR-EVER ).
The greater attention to the environmental impact and sustainability of oenological practices has highlighted the high energy consumption of refrigeration, a technique widely used in the cellar for tartaric stabilization but not always reliable in the precipitation of calcium. Refrigeration also involves enrichment in oxygen, the loss of aromas and color in reds and rosés.
R&D of EVER has developed the specific “CAL-STAR” program with the use of STABTAR Cationic Resin machines, to selectively retain Calcium through the exchange with Potassium, which can be easily stabilized with the STABILISSIMA range even in the presence of high concentrations of this cation.
EVER‘s “CAL-STAR” program allows the winemaker to obtain the removal of calcium “in line” in clear, but not necessarily brilliant, wines, a necessary condition with the other techniques mentioned above. Furthermore, the subtraction of calcium can be managed by the oenologist according to his needs and does not involve days of waiting and subsequent filtrations for the retention of tartrates.
The range of STABTAR systems allows the Calcium removal treatment from small to large masses of wine. The automated management of these systems makes the operation easy and safe.
Contact the EVER Technical Service (tel: +390421 200455; info@ever.it ) for further information
TEST EXAMPLE with STABTAR 50:
The treatment of 60hL of 2020 sparkling base white wine, represented below (Figure 1), allowed to reduce the calcium of the treated mass, from 115 mg/L to 78 mg/L. The wine had been clarified, filtered and stored in the tank for several months.
