Enhancing the Analytical and Sensory Quality of Warm-Climate Tempranillo Wines Through Co-Inoculation with Lachancea thermotolerans and Metschnikowia pulcherrima

Using non-Saccharomyces yeasts is a promising way to modulate wine composition, particularly in warm regions where high sugar levels result in wines with high alcohol content and low acidity. This study examined the impact of various inoculation methods involving Lachancea thermotolerans and Metschnikowia pulcherrima on the chemical and aromatic profiles of Tempranillo wines. Five treatments were tested: a control with Saccharomyces cerevisiae; two sequential inoculations, with each non-Saccharomyces species followed by S. cerevisiae; and two co-inoculations of both species at different ratios, followed by S. cerevisiae. L. thermotolerans was found to significantly increase lactic acid levels, resulting in higher acidity and lower pH, particularly at higher doses. Wines inoculated with M. pulcherrima exhibited the highest levels of fruity esters, whereas L. thermotolerans increased higher alcohols, acetaldehyde and ethyl lactate, but reduced ester content. Co-inoculations produced intermediate or synergistic effects, depending on the proportions of the yeast species. Aromatic analysis indicated that treatments involving M. pulcherrima were associated with higher contributions to the fruity, floral and waxy aromatic series, while L. thermotolerans increases creamy series. Multivariate analysis clearly differentiated wines according to the dominant species. Overall, the co-inoculation of both yeasts is an effective method of modulating volatile composition and aroma-related parameters in warm-climate red wines.