Effects of Must Settling and Pre-Bottling Filtration in Ancestral Sparkling Wine Production

The ancestral method of sparkling wine production requires no sugar addition and is based on a single alcoholic fermentation that finishes in the bottle. It has recently gained popularity among both natural and conventional producers due to its capacity to expand sparkling wine portfolios and its advantages for sparkling wine production in warm regions such as the Mediterranean basin. However, some technological and other key aspects of the process remain poorly defined. This study investigates how must settling (using pectolytic enzymes) and pre-bottling filtration influence the physicochemical composition, colloidal structure, foaming properties, volatile profile, and sensory attributes of ancestral sparkling wines. Macabeo grapes (2023 vintage) were vinified under four treatment combinations of these two operations, and the wines were analysed after eighteen months of lees ageing. Significant differences were observed in total polyphenol index, titratable acidity, macromolecular composition, and colloidal particle concentration. Non-settled wines exhibited higher colloidal loads and lower foamability, whereas settling and filtration improved foam height and stability. Volatile (GC-Headspace) analysis showed that settled wines contained higher concentrations of fruity and floral esters, while non-settled and non-filtered wines had greater levels of volatile phenols and volatile acids associated with unpleasant aromas. Sensory assessment confirmed perceptible differences between treatments, particularly in phenolic, fruity/floral, and Maillard reaction aromaticity. These findings provide insights into the impact of two critical oenological practices on wine stability and aroma and provide technologically relevant guidance for optimizing quality in this emerging sparkling-wine category.