Effects of ultrasonic riddling on the physical and sensory properties of sparkling wine

Riddling (remuage) is a crucial step in the production of sparkling wine obtained with Champenoise method. This step consists in systematically rotate and tilt the bottles for collecting the yeast lees in the bottle neck that are then removed by the disgorgement. Traditionally, the remuage has been manually performed by pu-pitres or using automated gyropalettes. However, this winemaking phase is labor-intensive and time-consuming, and requires experience, especially for the riddling by pupitres. Moreover, co-adjuvants (e.g., alginate and/or bentonite) are often added to facilitate yeast lees precipitation and aggregation consequently ensuring the clarity of sparkling wine. This study explored the innovative application of ultrasound to shorten the rid-dling process while assessing the potential to avoid the use of co-adjuvants for commercial and sustainability benefits. To evaluate the sensory aspects, a triangu-lar sensory test was conducted on an initial set of bottles. For chemical-physical analysis, a second batch of bottles was used to measure key parameters, including foam height and persistence, and turbidity. A custom-designed system for foam analysis incorporating an automated pouring mechanism, imaging software, and statistical tools was employed to assess foam characteristics. Turbidity was measured using a nephelometric turbidimeter for precise clarity evaluation. Preliminary results indicated that ultrasonic riddling had no significant undesired effects on sensory properties. The use of ultrasounds led to potential advantages, as sediment collection facilitated by acoustic cavitation was faster, enhancing the yeast lees deposition efficiency. Moreover, the ultrasounds seemed to ensure the sparkling wine clarity even in the absence of co-adjuvants. However, further remuage tests are required to fully address the feasibility of coadjuvants removal