Effect of an electric field on the heterogeneous nucleation and crystal growth of potassium hydrogen tartrate in wines

Potassium hydrogen tartrate (KHT) is a naturally occurring salt in wines. To avoid the formation of KHT crystals in bottles, it is necessary to stabilize wines before bottling. However, none of the current techniques is fully satisfactory. A new process, called the 'trap process', has been developed that consists of cold-crystallizing KHT on a stainless steel packing. To accelerate the heterogeneous nucleation and/or crystal growth rate of the salt, the influence of an external electric field on these phenomena was studied. A potentiostatic circuit maintained a constant potential against a saturated calomel electrode. A preliminary cyclic voltammetry study led to the determination of the most suitable potential values (i.e., inducing no electrochemical reaction). A set of wine stabilization experiments was then performed using the 'trap process' with and without potential. The results demonstrated that a potential of +200 mV vs SCE generates an increase in process efficiency, even in the case of wines containing a lot of inhibitors. It also significantly reduces the induction time of nucleation.