Pied-de-cuve: A sustainable approach to microbiological control in organic and natural wines

Identifier:  imarina:9470727

Handle: https://hdl.handle.net/20.500.11797/imarina9470727

Authors:  Mas A; Portillo MC

Abstract:
The use of selected yeast is one of the main achievements of microbiological control in the wine industry. However, the reliance on single-strain Saccharomyces cerevisiae starters and limited strain diversity has led to objections to its use. Recent trends in winemaking emphasize the importance of microbiological “terroir” and challenged the use of commercially selected starters sourced from other regions. Among the approaches to fight this concept are the wines produced with spontaneous alcoholic fermentation which preserves the native microbiota. However, spontaneous fermentation poses significant risks, including sluggish or stuck fermentation and increased spoilage potential due to the lack of microbial control. To address these challenges, we are proposing the application of the “Pied-de-cuve” (PdC) method as an alternative. PdC has been traditionally used in sparkling wine production to acclimate yeasts to the alcohol content of the base wines for the second fermentation. Our proposal is the preparation of the PdC using spontaneous fermentation in diverse winemaking conditions, such as addition of SO2, fortification with ethanol and temperature adjustments. We performed laboratory trials to optimize PdC preparations, ensuring effective fermentation while preserving the diversity of the yeast consortia used to mimic the natural populations in grape must. The optimal selection was validated at cellar scale with natural must and its microbiota. Under these conditions, the PdC methodology exhibited fermentation kinetics comparable to, or better than, those achieved commercial inoculum. Furthermore, wines fermented using PdC demonstrated greater microbial diversity during and after fermentation and resulted organoleptically different compared to the inoculated controls. Here, we highlight the PdC as a viable method for achieving microbial control of alcoholic fermentations if the preliminary fermentation is appropriately handled. The proposed PdC protocol can be easily adapted to organic, biodynamic, or natural winemaking practices, offering a balanced approach to microbial management and “terroir” expression.