Discovering Erbamat: characterization and oenological potential

In the context of climate change, increasing grape ripeness and sugar accumulation are associated with a loss of acidity, posing a significant challenge for sparkling wine production. A possible response to mitigate the climate change is represented by ‘Erbamat’ variety (Vitis vinifera L.), an autochthonous cultivar cultivated in Brescia area (Lombardy, Italy). This variety has received attention from both the scientific community and the wine industry due to its distinctive agronomic and compositional traits, including high titratable acidity, moderate sugar content, and late ripening. Due to these characteristics, ‘Erbamat’ grape was recently admitted for the production of Franciacorta DOCG. However, the current knowledge of this grape variety is limited in terms of both composition and its impact on sparkling wine. The study aimed to the characterization of ‘Erbamat’ variety and the evaluation of its oenological potential addressed to the sparkling wine production. Erbamat grape were collected in harvests 2023 and 2024. Experimental musts were produced by pressing whole bunches and after destemming. These musts were used for the production of base wines. Triplicate fermentations with and without maceration were carried out in harvest 2023. Instead, in harvest 2024, musts from whole bunches and destemmed berries were divided in 2 aliquots and a cryomaceration step was performed for one aliquot of each must. Must and base wine samples were characterized in terms of general chemical parameters and phenolic indexes. Pressing methods had a negligible impact on must composition. However, significant vintage-dependent differences were observed in must samples: grapes harvested in the 2024 vintage led to musts with lower sugar content and pH, and higher titratable acidity. Cryomaceration resulted in a negligible increase in pH and in a marked decrease in titratable acidity (of approximately 1 g/L tartaric acid). The base wines showed a relevant titratable acidity in particular for harvest 2024. The destemming seemed to affect the acidity that resulted lower in those base wines. However, Chardonnay base wines produced in the same conditions in harvest 2024 had a much lower titratable acidity (6.7±1.7 [n=6] vs. 11.3±1.2 g/L tartaric acid for Chardonnay and Erbamat wines, respectively). These results demonstrate the suitability of the ‘Erbamat’ grape variety as an acidity regulator, with its impact on sparkling wine during aging on yeast lees being evaluated.