Fining of Pinot noir wine with egg white: potential for residual protein and early sediment formation

Abstract

In recent years consumer demands have been for wine to be rapidly processed and available in the market place earlier than would have traditionally occurred. This has lead to the introduction of various winemaking techniques for the stabilisation and clarification of wine so as to be palatable immediately, and free from hazes and sediments.

This study was undertaken to examine the effect of egg white fining on changes in protein concentrations in Pinot noir wines, and to relate this to a potential instability problem, which manifests as a haze/sediment soon after bottling. Accelerated aging was used to indicate the potential of the Pinot noir wines fined with spray dried egg white, to form haze/sediment.

The addition of spray dried egg white to two different styles of Pinot noir wine, a 'heavy' style and a 'light' style (less colour and less phenolics than 'heavy' style) from two different vintages (1998 and 2000 vintages respectively), resulted in residual protein and specifically egg albumen, remaining in solution following clarification by fining. Furthermore, it was shown that the wines fined with spray dried egg white were susceptible to haze/sediment formation following accelerated aging. Two techniques, silica sol co-fining and cold stabilisation were investigated as possible methods for reducing the potential of the wines to form haze/sediment. Co-fining with silica sol was partially effective in reducing the potential for haze/sediment formation following accelerated aging in 'light' style (2000) Pinot noir wine, whereas cold stabilisation was effective in preventing haze/sediment formation following accelerated aging in both 'light' style (2000) and 'heavy' style (1998) Pinot noir wine.

The potential of wine to form haze/sediments is discussed in relation to proteins and phenolics, and their complex formation and equilibrium. A simple model explaining protein and phenolic interactions that can lead to haze/sediment formation is discussed.