Effects of abscisic acid treatment on Vitis vinifera L. Savvatiano and Mouchtaro grapes and wine characteristics

Climate is the major factor influencing the dynamics of the vegetative cycle and can determine the timing of phenological periods. Knowledge of the phenology of varieties, their chronological duration, and thermal requirements, allows not only for the better management of interventions in the vineyard, but also to predict the varieties’ behaviour in a scenario of climate change, giving the wine producer the possibility of selecting the grape varieties that are best adapted to the climatic conditions of a certain terroir. In 2014, Symington Family Estates, Vinhos, established two grape variety libraries in two different places with distinctive climate conditions (Douro Superior, and Cima Corgo), with the commitment of contributing to a deeper agronomic and oenological understanding of some grape varieties, in hot climate conditions. In these research vineyards are represented local varieties that are important in the regional and national viticulture, but also others that have over time been forgotten — as well as five international reference cultivars. From 2017 to 2021, phenological observations have been made three times a week, following a defined protocol, to determine the average dates of budbreak, flowering and veraison. With the climate data of each location, the thermal requirements of each variety and the chronological duration of each phase have been calculated. During maturation, berry samples have been gathered weekly to study the dynamics of sugar accumulation, between other parameters. The data was analysed applying phenological and sugar accumulation models available in literature. The results obtained show significant differences between the varieties over several parameters, from the chronological duration and thermal requirements to complete the various stages of development, to the differences between the two locations, confirming the influence of the climate on phenology and the stages of maturation, in these specific conditions.

The quality of grapevines measured by yield and must density in the northern part of Europe conditons can be characterized as a type of “cool climate” – vary strongly from year to year and from one production site to another. One hundred year observations in Johannisberg from 1890 to 1991 demonstrate for the yield formation a clear dependancy from the year combined with a steady increase in productivity; latter a proof of positive clonal selection efforts.

Research is focused on the increase of the field of obtaining the wine yeast, under physical and chemical conditions. Study of different influences on yeast production is very important for the promotion

This interaction is primarily due to an acidic attack on the ceramic by the wine. It results in (1) the dissolution of the ceramic into the wine and the release of a wide variety of elements; and (2) an increase of the wine pH. The extent of these effects depends on the mineralogical and chemical composition of the ceramic, as well as the hydraulic ratio of the ceramic-wine system (the term hydraulic ratio (ρ) defines here the volume of wine over the surface area of the ceramic in contact with the wine).

Dada la importancia de los suelos y de los substratos geológicos en la zonificación vitivinícola, los autores realizan una revisión de estudios sobre las formaciones más importantes en la D.O. Jerez-Xérès-Sherry y Manzanilla-Sanlúcar de Barrameda.