In-line sensing of grape juice press fractioning by UV-Vis spectroscopy

Why grape juice press fractioning? For quality sparkling wine production, it is important to ensure that the correct phenolic profiles of the juice press fractions are separated: free run, cuvée and taille. The current options for press fractioning are based on volumetric cuts, sensory evaluation and conductivity.

As explained by Robert Dambergs, UV-Visible spectroscopy in conjunction with chemometrics, was successfully applied to objectively differentiate sparkling wine press juice fractions. Two measurements methods were applied: reflectance using a fibre optic probe in-line and transmission using a benchtop spectrophotometer.

According to this research, in line press monitoring done in real time is reliable and once a system is set up, you can be sure of the results: if you apply analytical methods in-line it is also cost-efficient and suitable for large scale wineries. This offers potential to make real time automated press cuts based on juice phenolic contact to improve efficiency of press operation and optimise quality of the press fractions.

Video of the seminar held during Enoforum Italia 2021 (18-20 May 2021)

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