A circular-economy strategy in oenology: using pomace from new grape varieties to improve red-wine colour

Abstract

Winemaking generates large quantities of grape pomace, a phenolic-rich by-product that is often underused. This study evaluated pomace from Myrtia, a new Monastrell × Syrah grapevine variety with high phenolic content, as a natural colour-correcting agent for red wines with low colour intensity. Experimental Monastrell microvinifications were conducted in 2025 using a control and two treatments supplemented at the start of alcoholic fermentation with 50 or 100 g/kg Myrtia pomace. Colour, phenolics, tannins, and anthocyanins were analysed by spectrophotometry and HPLC. Pomace addition significantly increased total phenolic content, approximately doubling the total polyphenol index and tannin concentration, and markedly improved colour intensity. Total anthocyanins also increased, while the higher dose produced the greatest rise in tannins. Sensory analysis showed improved colour and aroma. The 50 g/kg dose provided the best balance, increasing aromatic intensity without herbaceous notes and maintaining pleasant mouthfeel. Although 100 g/kg further intensified colour, it increased astringency and dryness and reduced overall harmony. Myrtia pomace is therefore an effective natural tool for improving red-wine colour and phenolic composition while supporting circular-economy strategies, although further vintages are needed to optimise dosage.

References

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Acknowledgements

The authors acknowledge the collaboration of the staff of the Jumilla Oenological Station.