A hybrid process comprising column adsorption and crossflow microfiltration was applied to reduce the unstable proteins of Pinot Noir wine and improve the permeate flux during wine microfiltration. The process was performed using a packed column with zirconium oxide and a ceramic membrane. Proteins and polyphenols were reduced by bentonite and activated carbon addition in order to evaluate their influence on permeate flux decline. The column adsorption process achieved a better protein stability and increased the permeate flux by 15-20%. The molecular weight range of 20-70 kDa could be related to unstable proteins or cause membrane fouling. The phenolic composition of wine was not affected by adsorption with zirconium oxide or the microfiltration process. (c) 2006 Elsevier Ltd. All rights reserved.