Measurements of the effects of wine maceration with oak chips using an electronic tongue

- Potentiometric electronic tongue applied to wine macerated with oak chips.
- Electronic tongue distinguishes wine macerated with different types of oak chips.
- Electronic tongue quantifies total and non-flavonoid phenolic content.
- Electronic tongue quantifies each type of oak chip in wine.
- Extractives from oak chips subjected to different treatments analysed by ESI-MS.

The use of oak products as a cheaper alternative to expensive wood barrels was recently permitted in Europe, which led to a continuous increase in the use of oak chips and staves in winemaking. The feasibility of the potentiometric electronic tongue as a tool for monitoring the effects of wine maceration with oak chips was evaluated. Four types of commercially available oak chips subjected to different thermal treatments and washing procedures and their mixture were studied. Ethanolic extracts of the chips were analysed using electrospray mass spectrometry and 28 phenolic and furanic compounds were identified. The electronic tongue comprising 22 potentiometric chemical sensors could distinguish artificial wine solutions and Cabernet Sauvignon wine macerated with different types of oak chips, quantify total and non-flavonoid phenolic content, as well as the concentrations of added oak chips. Using measurements at two pH levels, 3.2 and 6.5, improved the accuracy of quantification.