Comparative study of red grape mustnanofiltration: Laboratory and pilot plant scales

Abstract

A consequence of global warming is the early ripening of grapes which promotes, among others, a higher fermentablesugar (glucose and fructose) content. This leads to wines with an alcoholic degree higher than desired.In this work, the main differences between red grape must nanofiltration at laboratory and pilot plant scale werestudied in order to perform the scale-up of a nanofiltration process to reduce the sugar content. For this, previousresults of the nanofiltration of commercial red must using the SR3 membrane in a flat sheet crossflow module werecompared with those obtained for the filtration of natural red must using the same membrane in a spiral woundmodule at two different applied pressures.The aim of this publication is to analyze the main differences between red grape must nanofiltration at laboratoryand at pilot plant scale.Results: showed that the flow destabilization and eddy promotion caused by spacers in the spiral wound modulemitigate the rate at which the cake thickens and compacts on the membrane surface. This causes a less sharp fluxdecrease, less variable sugars rejection and osmotic pressure difference. Moreover, higher applied pressure promotesa higher membrane fouling and osmotic pressure that worsen the flux decay