II.3.1.1.5 Acidification by cation exchange treatment

Definition:

Physical partial extraction of cations from the wine to increase titration acidity and actual acidity (decrease in pH) through cation exchanger

Objectives:

a)        Increase titration acidity and actual acidity (decrease in pH)

b)       Refer to objectives in the general file II.3.1.1. Acidification

Prescriptions:

a)        The treatment will be performed using cation exchange resins regenerated in the acid cycle.

b)       The treatment must be limited to the elimination of excess cations.

c)        To avoid the production of fractions of wine, the treatment will be performed continuously, with in-line incorporation of the treated wine into the original wine.

d)       As an alternative, the resin could be directly introduced into the tank of must, in the quantities required, then separated by all appropriate technical methods

e)       The acidification must be carried under condition that the initial acidity is not raised by more than 54 meq/L. When must and wine are acidified, the cumulative net increase must not exceed 54 meq/L.

f)         All operations will be placed under the responsibility of an oenologist or qualified technician.

g)        The resins shall comply with the prescriptions of the International Oenological Codex.[1]

Recommendation of the OIV:

Admitted

[1] - The treatment must not decrease the concentration of metallic cations in the wine below 300 mg/l.

- The treatment must not lower the wine's pH below 3.0.  The decrease in pH should not exceed 0.3 pH units.