A regional starter for higher quality wines: an Argentinean Patagonia experience

Abstract

The demands of an increasingly competitive international market suffering from oversupply, and consumer demand for new styles of wine, impose challenges to winemakers that require technological innovation. Within the productive chain, appropriate management of the yeast biota responsible for conducting the alcoholic fermentation is strategic to differentiate the character of wine. The objective of this study was to characterize the ability of a Patagonian Saccharomyces cerevisiae strain to drive red vinifications and to improve the quality of the regional wines. Pilot scale vinifications (200 L) were carried out in Pinot noir, Merlot and Malbec varieties, during three consecutive vintages (2012 to 2014). Sulfited musts industrially obtained were inoculated with S. cerevisiae ÑIF8-LVI, an autochthonous strain, (initial cellular density of 106 cel/mL). Alcoholic fermentation (AF) was followed by ºBaumé and total reducing sugars, and implantation capacity was studied by viable counts in GPY agar and restriction profile analysis from mitochondrial DNA with Hinf I endonuclease. In all cases, assays with a S. cerevisiae F15 (Laffort), a commonly used commercial starter, were carried out as a comparison. When alcoholic fermentations were finished, wines were devatted and transferred to the 50 L tanks where spontaneous malolactic fermentation (MLF) developed at 202ºC. They were stabilized, clarificated, filtered and bottled. Quality was evaluated through physicochemical parameters (INV and enzymatic methods), sensorial analysis and consumer preference polls. Both indigenous and commercial starters were able to satisfactorily implant, yielding normal processes and products. However, S. cerevisiae ÑIF8 vinifications showed significantly faster kinetics than F15 controls and the oenological characteristics of these wines were significantly improved, allowing to obtain a higher score than controls in the sensorial evaluation and to be preferred for the consumers (paired-preference test p<0.05). These results reassure the oenological potential of S. cerevisiae ÑIF8 strain for the formulation of a regional starter culture already confirmed at laboratory scale.