Effects of soil characteristics on manganese transfer from soil to vine and wine

Amphora wines are known in Portugal as Vinhos de Talha. In this technology, alcoholic fermentation takes place in clay vessels that traditionally were pitched inside using pine pitch. Vinhos de Talha has a distinctive sensorial profile, due to the ancestral technique of vinification. However nowadays, some clay vessels are impermeabilized with other materials than pitch, such as bee wax and mainly epoxy resins.

Copper (Cu) is known to substantially impact wine stability through oxidative, reductive or colloidal phenomena. Recent work has shown that Cu exists predominantly in a sulfide-bound form, which may act as a potential source of sulfidic off-odours in wine and hence contribute to reductive flavours

Viticulture is facing two major challenges – climate change and agroecological transition. The soil plays a pivotal role in these transition processes. Therefore, soil quality and adequate soil management are key levers for an ecologically and economically sustainable viticulture. Over the last 15 years, numerous studies evidenced strong effects of viticultural practices on the soil physical, chemical and biological quality. However, to date a global analysis providing a comprehensive overview of the ecological impacts of viticultural practices on soil biological quality is missing.

It is fundamental for wineries to know the potential yield of their vineyards as soon as possible for future planning of winery logistics. As such, non-invasive image-based methods are being investigated for early yield prediction. Many of these techniques have limitations that make it difficult to implement for practical use commercially. The aim of this study was to assess whether yield can be estimated using images taken in-field with a smartphone at different phenological stages. The accuracy of the method for predicting bunch weight at different phenological stages was assessed for seven different varieties.

Today the knowledge in terms of molecular composition of the colloidal matrix is ​​not enough in order to control its stability, according to the number of winemaking and wine stabilization processes. The physico-chemical processes during the winemaking change the composition and quantity of wine macromolecules. The goal today is to determine which analytical techniques will allow to discriminate these winemaking processes in order to better understand their impact on colloidal matrix stability as well as which molecules are responsible for its instabilities. METHODS: Wines obtained after conventional winemaking were subjected to different fining and chemical stabilization treatments. Different methods were used to investigate the wine macromolecular composition and stability after chemical stabilization, including quantitative and qualitative analyzes of total soluble polysaccharides by extraction under acidified ethanol, and by size exclusion separation as well as qNMR metabolomics. RESULTS: Observation of a slight difference at the quantitative level using classical analysis between the winemaking processes was observed as well as a strong discrimination by qNMR metabolomics.