Effects of vineyard irrigation regimes and yeast inoculation strategies on fermentation dynamics and wine sensory profile

Alcoholic fermentation of wine is influenced by vineyard management, nutrient availability, and inoculation strategy, all of which shape microbial succession and the wine’s sensory and analytical traits. This study investigated the effects of conventional vineyard management (NIT) versus late irrigation (IT), combined with either a commercial Saccharomyces cerevisiae starter (SA) or spontaneous fermentation (SP), on sugar consumption, yeast dynamics, volatile composition, and wine characteristics. SA fermentations showed consistent, linear sugar consumption, while SP fermentations were more variable due to indigenous yeast competition, confirmed by next-generation sequencing (NGS). IT musts started with higher yeast loads (7.5–7.9 log CFU/mL) than NIT (7.2–7.3), yet NIT fermentations exhibited faster early sugar consumption and yeast growth, likely driven by better nutrient bioavailability. Volatile analysis (SPME-GC/MS) showed 8–10% more volatiles in IT wines, especially alcohols (167–255 ppm eq.) and esters (218–289 ppm eq.). SP- IT samples were rich in ethyl acetate and phenylethanol, while SA wines had more fatty-acid esters and acetic acid. SA-IT wines had higher total acidity, alcohol, and glycerol than SA-NIT, which showed higher pH. SP-NIT wines displayed deeper color and more phenolics, while SP-IT wines were more acidic and astringent. Sensory analysis confirmed these differences: SA-IT wines had richer color, fuller body, and greater complexity; SA-NIT wines were more aromatic with softer tannins. SP-NIT wines achieved balanced aromatics, whereas SP-IT wines were brighter and firmer. In summary, NIT favored aromatic expression and smoother mouthfeel, while IT enhanced structure, acidity, and persistence. In conclusion, vineyard water management and fermentation protocol jointly modulate not only the rate and efficiency of sugar metabolism but also yeast ecology, aromatic development, and the ultimate sensory character of the wine.