Irrigation of Grapevines with Sewage Effluent. II. Effects on Wine Composition and Quality

Abstract

The use of sewage effluent water for the irrigation of grapevines significantly altered the chemical composition of wines. Sodium and chloride levels in wines from effluent treatment were considerably higher than is usual for Australian red wines. While higher concentrations of total nitrogen, magnesium, potassium and phosphorus were found in wines from vines receiving 135 L effluent/week (compared to vines receiving 45 L effluent/week or 135 L good quality mains (reservoir) water/ week), concentrations were not much beyond the range reported for Australian Shiraz wines. Higher potassium concentration in wine was associated with increased pH, duller color hue, decreased ionization of anthocyanins and a greater 'chemical age.' Although the majority of industry wine tasters in a panel detected significant differences between wines from the various irrigation treatments, they were divided in their preferences.