Commercial Yeasts — Selected Strains

Commercial yeasts are pure cultures of selected Saccharomyces cerevisiae strains, and increasingly certain non-Saccharomyces species, cultivated, quality-tested, and distributed by specialized laboratories for winemaking. While Louis Pasteur's mid-19th century research demonstrated that yeasts on grape skins are responsible for spontaneous fermentation, the practice of inoculating pure yeast cultures into must did not take hold commercially until around 1890. Lallemand began producing and selling wine yeast strains isolated from different wine regions in 1978, helping to transform inoculated fermentation into standard winemaking practice worldwide. Before the availability of active dry yeasts, winemakers had to propagate their own starter cultures from cellar collections, a labor-intensive process with high contamination risk.

• Pasteur's mid-19th century research identified yeasts on grape skins as the agents of alcoholic fermentation, laying the scientific groundwork for pure culture selection
• The practice of inoculating pure strains for wine fermentation became established around 1890, according to historical wine timelines
• Commercial strains are most commonly supplied as active dry yeast (ADY), lyophilized for stability, with recommended storage at 4°C to minimize loss of viability

Selected yeast strains fundamentally shape fermentation kinetics, residual sugar profiles, and aromatic expression in finished wines. By choosing a specific strain, winemakers direct the production of volatile compounds, including esters, thiols, and higher alcohols, that would otherwise be left to unpredictable wild microbiota. This control is critical in commercial production where vintage variation, regulatory compliance, and brand consistency require reproducible outcomes. Research confirms that even when a commercial strain is added, ambient and non-Saccharomyces yeasts may still contribute to fermentation to varying degrees, meaning strain selection and inoculation practice both matter.

• Strains differ considerably in nitrogen demand, fermentation temperature range, alcohol tolerance, and volatile compound production, allowing targeted style decisions
• Thiol-releasing strains activate cysteine-bound precursor compounds during fermentation, liberating volatile aromatics such as 3-mercaptohexanol (3MH) and 4-methyl-4-mercaptopentan-2-one (4MMP)
• Non-Saccharomyces strains such as Torulaspora delbrueckii, when used in sequential inoculation, can reduce volatile acidity, increase glycerol, and enhance ester and terpene complexity

The influence of yeast strain selection is expressed through aromatic intensity, ester profiles, texture, and acidity in the finished wine. High polysaccharide-producing strains like ICV D47 contribute roundness and weight on the palate, while high ester-producing strains like Lalvin 71B express isoamyl acetate, described as banana and pear. Thiol-releasing strains used in Sauvignon Blanc amplify passionfruit, grapefruit zest, and herbaceous aromatics from grape-derived precursors. Clean, neutral strains like EC1118 produce wines with minimal yeast-derived aromatic signature, preserving terroir and varietal character. Laboratory analysis via gas chromatography can identify yeast-derived metabolites precisely, while trained tasters can often infer strain characteristics from aromatic and textural patterns.

• ICV D47 in white wines produces full-bodied, complex profiles with citrus, stone fruit, tropical fruit, and floral aromas, especially when left on lees
• EC1118 fermentations show extremely low volatile acid and H2S, a neutral aroma contribution, and compact lees with good flocculation
• Lalvin 71B is characterized by isoamyl acetate (banana, pear) driven fruit expression and a softer acid profile due to partial malic acid metabolism

Several strains have become reference points in the global wine industry. Lalvin EC1118, selected from Champagne fermentations, is used worldwide for sparkling wine base fermentation and secondary fermentation in bottle, valued for its competitive factor, wide temperature tolerance, and neutral profile. Lalvin QA23, selected in Portugal's Vinho Verde region, is widely adopted for Sauvignon Blanc production because of its exceptional thiol-releasing and beta-glucosidase activity. Lalvin ICV D47, from the Côtes du Rhône, is a benchmark strain for premium barrel-fermented Chardonnay. In red wine production, strains such as Lalvin BM45 and RC212, the latter isolated by the Bureau Interprofessionnel des Vins de Bourgogne (BIVB), are preferred for varieties like Pinot Noir where polyphenol management and color stability are priorities.

• Lalvin EC1118: selected from Champagne, used globally for sparkling wine primary and secondary fermentation, alcohol tolerance up to 18% v/v
• Lalvin QA23: selected in Portugal's Vinho Verde region, recommended for Sauvignon Blanc, Viognier, Chenin Blanc, and other aromatic whites requiring thiol expression
• Lalvin RC212 (Bourgovin): isolated by the BIVB in Burgundy, selected for its ability to highlight Pinot Noir polyphenol potential and color stability

Yeast strain selection functions synergistically with fermentation temperature, nutrient availability, must composition, and pH. The standard inoculation rate of 25 g/hL of active dry yeast targets approximately 5 million cells/mL in the must, providing a competitive population that suppresses wild microbiota. Nitrogen management is critical because deficiency reduces cell population size and ethanol tolerance, risking stuck fermentation, while adequate yeast assimilable nitrogen supports healthy fermentation kinetics. Temperature control during fermentation determines ester retention, thiol expression, and the degree to which non-Saccharomyces yeasts persist alongside the inoculated strain. The rise of commercially available non-Saccharomyces strains, led by Torulaspora delbrueckii, Lachancea thermotolerans, and Metschnikowia pulcherrima, has expanded the toolkit available to winemakers seeking greater aromatic complexity.

• Inoculation at 5 million cells/mL is the widely accepted standard; under difficult fermentation conditions (high sugar, low turbidity), a higher inoculation rate is recommended
• Nitrogen additions (DAP or organic nitrogen sources) support yeast health and reduce the risk of H2S formation, particularly for strains with high nitrogen demand
• SO2 management protects the fermentation from spoilage organisms such as Brettanomyces, which would otherwise mask yeast-derived aromatic expression