## 4 Materials and Methods  
### Experimental Design and Plant Material  
A commercial vineyard (La Madunina), located in northern-east Italy (Friuli-Venezia Giulia region, Sequals, PN), of Sauvignon Blanc (_Vitis vinifera_ L.) was chosen to test a commercial DYE product (\"LaVigne(tm) AROMA\", Lallemand Inc., Montreal, QC, Canada) in 2020 and 2021. The choice of the experimental sites was based on the high degree of homogeneity of the vineyards, on the presence of long rows (200 m) allowing sampling from several independent plants arranged in randomized blocks without impacting the fruit load, and on the fully mechanized conduction of the vineyard, further ensuring homogeneity. The meteorological data (Figure S1) in Sequals was evaluated and determined to show no significant differences in terms of temperature or annual precipitation between the years 2020 and 2021 (1941 and 1971 mm, respectively). During the summer months (July to September), there was a slight change in precipitation during the two vintages (in 2020, approximately 500 mm, while in 2021, around 370 mm).  
Six rows were treated, and an additional six rows were kept without treatment and used as a control. The two groups of six rows were separated by an additional two rows to avoid the drift effect of the product. All the treatments were carried out in the early hours of the morning through a double tunnel recovery atomizer adopting the recommended dosage (10g/L; 3 Kg/Ha) [109].  
The treatments with DYE were performed as indicated in Figure 10. In 2020, the first treatment was carried out when 5% of grapes reached veraison (\({}^{0}\)Brix \(\geq\) 7) [109]; the second treatment was carried out 11 days later, and the sampling was performed 24 h after each treatment. Finally, a further sampling was carried out on the day of harvest (H). In 2021, as in 2020, the first treatment was executed at the beginning of veraison. A second DYE treatment (TP2) was performed 10 days after the first treatment, and sampling occurred 48 h after each treatment and at H. In this latter vintage, a third sampling was performed between the second treatment and H.  
Figure 10: Experimental design of treatments of Sauvignon Blanc with DYE and sampling for the two years 2020 (**A**) and 2021 (**B**). On both years, Sauvignon Blanc vineyards were sprayed with the DYE at the beginning of veraison and again after a period of 9–11 days from the first treatment. Sampling was performed 24/48 h after each treatment (TP1 (EL36, 10.1–14 \({}^{0}\)Brix) and TP2 (EL37, 14.1–18 \({}^{0}\)Brix)) and at H (EL38, 18.1–22 \({}^{0}\)Brix). In the year 2021, an additional sampling, TP3 (EL38, 18.1–22 \({}^{0}\)Brix), was performed between TP2 and H.  
Three biological replicates were sampled for each experimental condition (DYE-treated and control) at each time point (TP). Each replicate was composed of a mix of berries sampled from three independent blocks, each consisting of two rows: the first and second row, the third and fourth row, and the fifth and sixth rows originated from replicates one, two, and three, respectively. From each block, five bunches were collected from each row, so that each replicate was finally obtained from a mixture of berries from ten bunches. Bunches were always collected from the same side of the row, guaranteeing that they were grown under identical sun exposure conditions. The samples were frozen with liquid nitrogen immediately after collection in the field, transported on dry ice, and then stored at \(-80\)\({}^{\circ}\)C for further analysis.