Membrane applications in the wine industry

The treatments required to produce wines and prepare them for bottling require the use of successive, restrictive filtrations. The traditional technologies available (centrifugation, alluvial filtration, vacuum rotary filtration, plate filtration) are used to their full potential to meet the new quality specifications set by distributors: absence of cloudiness, brilliance, microbiological stability, tartaric stability of wines.

The development of membranes and equipment adapted to the characteristics of wines has enabled tangential microfiltration (MFT) to guarantee limpidity and microbiological stability in a single operation. It guarantees the quality of the wine treated, and thus meets the demands of users of this process by obtaining products with low turbidity (less than 1 NTU), low germ content (average pore diameter is 0.2 µm) and by preserving the organoleptic characteristics of the wines. Users of this technology can therefore benefit from a wide range of applications.

The winemaker can use MFT to treat a raw wine as soon as malolactic fermentation is complete, and obtain a clear, microbiologically stable wine in a single step, compatible with good product quality and suitable permeation flows. This application on raw wines has a number of other oenological benefits:

• malolactic fermentation control ;

• control the evolution of volatile acidity by a controlled reduction, until the complete elimination of contaminating bacteria;

• significant reduction in the use of SO ₂ on microfiltered wines.

The winemaker or merchant can also MFT a wine at any time they deem appropriate in the wine's evolution or maturation cycle.

Pre-clarification or stabilization of wines by fining, centrifuging or alluvial filtration enhances the performance of the tangential filter. This is essentially due to the reduced particulate load of pre-treated wines. Wines treated with fining must, however, be carefully racked to avoid bringing abrasive or clogging particles into contact with the membranes.

Finally, compared with traditional processes, there are many advantages to be taken into account: continuous operation, high levels of automation, reduction in the amount of consumables required for conventional filtration (plates, additives), reduced quantities of rejects or product losses.

The positioning of the MFT leads to a significant simplification of work by shortening the technological chain. Coupling with the electrodialysis technique, another newly authorized membrane technique referenced in oenology, is proposed....