Understanding Natural and Inoculated Fermentation Effects on Aroma, Flavor
Winery: Chateau Ste. Michelle
Grape Variety: Chardonnay
Winemaker: David Rosenthal
Trial Objective: To compare wines inoculated with commercial stains of yeast with wine fermented naturally.
Trial Description: Each year we ferment certain wines naturally, or without adding commercial yeast. For certain wines, we prefer the softer texture and more complex flavor profile of the natural wines. However, we like to compare natural wines to wines made with commercial yeast. In this trial, we took grapes from two vineyard sites, Cold Creek Vineyard and Canoe Ridge Estate Vineyard, and we added commercial yeast to some, while leaving the remainder to ferment naturally. The grapes from Cold Creek were pressed and we added yeast nutrients to a standard rate. Then juice was sent to barrel to fill a certain number of barrels representing the natural portion of the trial. CY3079 yeast was then added at a rate of 1#/1,000gal to the remaining juice and then sent to barrel. The process was identical for the Canoe Ridge lots, however Montrachet yeast was used for the inoculate portion of the trial. The wines went through primary and were inoculated for malolactic fermentation. The wines were stirred and topped weekly through ML fermentation and sulfur dioxide was added when it was complete. The wines were then stirred once a month.
Lot 1: Canoe Ridge - Natural ferment
Lot 2: Canoe Ridge - Montrachet yeast
Lot 3: Cold Creek - Natural ferment
Lot 4: Cold Creek - CY3079 yeast
Trial Conclusion: Overall, fermentation rates between natural and inoculated wines are similar, although there is more of an initial lag phase with the natural wines. Nutrient requirements are similar. Anecdotally, we find naturally fermented wines tend to go through ML fermentation faster. In sensory tests, we find naturally fermented wines to be softer on the palate with more gun flint and minerality. Inoculated wines tend to be more fruit forward and have more structure.
