Evaluation of Sensory Thresholds and Perception of Sodium Chloride in Grape Juice and Wine

Abstract

Poor water quality and lack of rainfall can lead to higher salt loads in vineyard soil and the production of wine with sodium chloride (NaCl) concentrations that may affect wine quality or exceed regulatory limits. Here, study 1 aimed to determine NaCl sensory thresholds in grape juice and wine so that better harvest and processing decisions could be made regarding salt-affected fruit. A whole-mouth gustatory method was used to determine detection and recognition thresholds of NaCl in water, red and white juices, and wines. The NaCl sensory thresholds were often within legal boundaries; thus, a significant proportion of wine consumers may detect salt in wines at concentrations below the legal NaCl limits. The detection and recognition thresholds of NaCl in grape juice and wine increased with panelist age. Study 2 investigated how NaCl affects wine sensory properties. Sensory evaluation using a trained descriptive analysis panel (n = 9) and chemical and elemental analyses were conducted on four Chardonnay wines made from separate vineyards where the fruit was perceived to contain varying degrees of saltiness and results were compared to Chardonnay wine samples spiked with 0.5 or 1 g/L NaCl. Wines made from fruit grown on salt-affected vines and wines spiked with NaCl had similar sensory characteristics. Salty and soapy attributes were correlated and associated with higher Na and Cl concentrations. Fruit expression was associated with wines containing less Na and Cl. When determining acceptable salt concentrations in juice and wines, winemakers need to consider sensory impacts, legal requirements, and who conducts the sensory assessment.