Berry maturity effects on physic and chemical characteristics of traditional sparkling wines produced from Chardonnay and Sauvignon blanc grapes.

Abstract

One of the consequences of global warming is the quick berry development giving rise to a disconnection between sugar accumulation and the formation of important quality minor compounds such as phenolics and volatile compounds being a huge challenge for the oenologist [1]. Thus, this phenomenon is forcing the search on strategies for maintaining the quality of wines despite this situation. One possibility is to make an early harvest with a low sugar concentration (18ºbrix) and advanced harvest for sparkling wine (20-21ºbrix) and afterwards to combine base wines properly and carry out the second fermentation trying to compensate the lack of secondary metabolites due to the quick berry development and higher alcohol degree of the second one, not adequate itself for sparkling wine. The aim of this study was to assess the chemical and physical characteristics, mainly volatile profile, and foaming properties of sparkling wines from grapes of Chardonnay and Sauvignon blanc
harvested both in two ripening stages after 9 months of aging. Also, mixtures between them at 50% were studied to assess the impact on the final characteristics of the sparkling wine. Volatile compounds were extracted using headspace solid phase microextraction (HS-SPME) and analysed by gas chromatography coupled to mass spectrometry as described by Ubeda et al. [2]. Foam properties were measured using the Mosalux procedure [3].
Volatile compounds followed the same trend respecting maturity degree in both varieties in some chemical groups. Thus, the general tendency in esters was to increase in the wines produced with grapes with an advanced ripening stage excepting some cases. With respect to terpenes, the tendency was like the esters. However, other compounds such as alcohols, acids and ketones did not follow a common line.
Respecting foaming properties, we could observe that, those treatments made with the Sauvignon blanc variety presented a higher maximum foam height (HM), compared to the Chardonnay treatments. Likewise, those early harvest treatments presented a higher maximum foam height. On the other hand, in both varieties, sparkling wines elaborated with early harvest grapes, presented a longer foam stability time. Blends between maturity stages were useful in balancing these wines.

References

[1] Pons et al. (2017) OENO One, 51(2), 141-146.
[2] Ubeda et al. (2019). Food Research International. 2019, 119, 554-563
[3] Maujean et al. (1990). Bulletin de l’OIV (France). 1990.