In a high-value wine market that is highly susceptible to counterfeiting, the ability to authenticate the contents without opening the bottle represents a paradigm shift.

The study by Kritzinger et al. demonstrates a non-invasive optical technique capable of distinguishing between red wines through sealed green glass.

The system employs near-infrared fluorescence (785 nm) and a special lens geometry that focuses the light within the wine, thereby eliminating the influence of the glass, including variations in its thickness and colour. The choice of 785 nm was based on a combined analysis of the transmission curves of the wine and the bottle, with the maximum transmission product occurring at around 750 nm; prolonged exposure tests did not reveal any photodegradation.

Twenty Australian red wines were analysed directly in their sealed bottles.

The results show that each wine has a sufficiently distinct fluorescence signature to enable it to be distinguished from the others. The analyses revealed a clear clustering by grape variety, confirming that the chemical composition of the wine is reflected in the measured spectrum. When the system was used to automatically classify the samples, it correctly identified all twenty wines tested.

In practical terms, this means that the optical signature measured through the bottle is distinctive enough to be used as a reliable authentication tool. The key finding is that a single spectrum at 785 nm is sufficient to distinguish between different wines, without the need for multi-wavelength matrices or sample preparation, as is currently the case.

For the bottling industry, this opens up the prospect of compact, rapid devices for brand authentication and protection throughout the supply chain.

Bibliographic references: Kritzinger, A., Mouthaan, R., Bruce, G. D., Wilkes, E., & Dholakia, K. (2026). Through the bottle authentication of red wine using near-IR fluorescence spectroscopy. arXiv. https://arxiv.org/abs/2601.08298