Mitarbeitende

The role of the invasive Robinia pseudoacacia in Switzerland has been subject of discussion in recent years. Besides ecological and silvicultural aspects, there could be considerable potential for products with high benefit at regional and national level. The combination of the specific wood with other products of the territory, such as wines and distillates, creates added value and could improve the image of the entire wood supply chain as well as the product appreciation by the public ("intangible value of the product"). Grappa distilled from Merlot grapes matured in Robinia wood-barrels has considerable potential as a niche product and in addition offers the possibility of an IGP-product (Indication Géographique Protégée) with controlled designation of origin - a quality label protected by Swiss law. The objective of the study was to describe the sensory and more specially the aroma characteristics of the local grappa aged in barrels of Robinia in comparison with grappa aged in barrels of oak wood. Three 50 liters test-barrels each, from Robinia and oak wood, were locally produced . These barrels were filled at Agroscope (Switzerland) at the end of November 2019 with Ticino Grappa (Merlot grape), which was previously distilled using a mobile distillery in Ticino (Switzerland). The barrels were stored at Agroscope during six month. Grappa ageing was monitored analytically and by a trained sensory panel for six months in order to gain a deeper understanding of different parameters and their effects on sensory characteristics. The analysis of odorant volatile compounds by gas chromatography coupled with mass spectrometry as well as olfactometric analyses efficiently complete the analyses. The aroma compounds present in the distillates come mainly from the type of grape variety, its fermentation and the volatile compounds generated during its distillation. Another important source is the maturation process of the distillates in wooden barrels. The type of wood as well as its quality and origin brings a wide range of volatile compounds (eg. lactones, phenols) and non-volatile compounds (eg. tannins) to the distillate. As example, the presence of oak lactones in distillates aged in oak barrels appears after only a few days and their concentrations increase with time, contributing to the aroma specificity of the product.