Nutrient Type and timing for low-pH base wines during yeast acclimatization and tirage in sparkling wine production Jessy Plante, Belinda Kemp, Esther Onguta and Debbie Inglis Cool Climate Oenology and Viticulture Institute, Brock University, St Catharines, Ontario L2S 3A1 (email: dinglis@brocku.ca) Introduction In addition to Chardonnay and Pinot Noir, Riesling base wine is also commonly used for the production of traditional method and Charmat method sparkling wines in Ontario, Canada. The secondary fermentation of sparkling wine requires the acclimatization of yeast to the base wine as the low pH, low nutrient concentrations, high acid, SO2 and high ethanol concentration of the base wine are challenging conditions for the yeast to grow in. No standard recipe exists for micronutrient additions during yeast rehydration or nitrogen additions during the adaptation and proliferation stages of tirage. Some groups recommend using 408.8 mg N/L (2000 mg/L DAP) additions during yeast adaptation and 68.1 mg N/L (333 mg/L DAP) during yeast proliferation (Valade and Laurent, 2015), while others believe that less is sufficient. Examples of smaller DAP additions during tirage include additions of 141.5 mg N/L (666 mg/L DAP) during the adaptation stage (Burrol et al. 2016) or 20 mg N/L (94.3 mg/L DAP) during the adaptation stage and 60 mg N/L (282.8 mg/L DAP) during the proliferation stage (Marti-Raga et al. 2016). Objectives: Determine the impact of yeast micronutrient additions during rehydration and nitrogen additions during adaptation (stage 2) and proliferation (stage 3) on yeast viability and sugar consumption during tirage To investigate ammonia assimilation during stages 2 and 3 of tirage. Methods Saccharomyces cerevisiae (EC 1118) No Go-Ferm® addition No DAP addition DAP addition (408.8 mg N/L) DAP addition (68.1 mg N/L) Go-Ferm® addition (1.25x mass of yeast) Stage 1 (0.5 hours) 6 g EC 1118 60 mL 35 oC water Total Volume: 60 mL Rehydration (Stage 1) 60 mL Rehydrated yeast 60 mL Liqueur (500 g/L sucrose in base wine) 60 mL Base wine Stage 2 (18 hours) Adaptation (Stage 2) Riesling Base Wine T.A. (g/L tartaric) 7.30±0.01 pH 2.85±0.01 YAN (mg N/L) 26.8±0.4 EtOH (% (v/v)) 10.6±0.2 SO2 Free (PPM) 8.4±0.1 Total (PPM) 56.5±0.2 Total Volume: 180 mL Stage 3 (88 hours) 180 mL Adapted yeast 300 mL Liqueur (500 g/L sucrose in base wine) 300 mL water 1020 mL Base wine Proliferation (Stage 3) T1 T2 T3 T4 Total Volume: 1800 mL Figure 1: Breakdown of treatments by nutrient additions during tirage for 4 replicates Figure 2: Yeast tirage protocol. Results Stage 2 Stage 3 Figure 4: Concentration of viable cells throughout stage 3. The combined treatment had the highest concentration of viable cells while the control had the lowest. Figure 3: Concentration of viable cells throughout stage 2. All treatments showed similar concentrations of viable cells throughout stage 2. Stage 2 Stage 3 Figure 5: Rate of sugar consumption throughout stage 2 shown as a decrease in specific gravity over time Figure 6: Rate of sugar consumption throughout stage 3 shown as a decrease in specific gravity over time and the time required to reach of specific gravity of 1.010 g/mL Conclusions and Future Research Yeast performance was improved during tirage when supplemented with Go-Ferm® during stage 1 and DAP during stages 2 and 3 The quantity of ammonia assimilated by yeast during tirage was 190 ± 50 mg N/L for the DAP treatment and 205 ± 20 mg N/L for the DAP + Go-Ferm® treatment. DAP and Go-Ferm® have a synergistic effect on yeast performance during tirage but Go-Ferm® does not impact assimilation of ammonia. The next step will be to determine if supplementing with Go-Ferm® and DAP during tirage improves yeast performance during the secondary fermentation. References Figure 7: Ammonia assimilation by yeast during the adaptation and proliferation. Similar nitrogen assimilation was observed for the DAP and DAP + Go-Ferm®. Burrol, A., Lopez-Martinez, G., Miro-Abella, E., Salvado, Z., Poblet, M., Cordero-Otero, R., Rozes, N. (2016) Food Microbiology 20-29 Marti-Raga, M., Marullo, P., Beltran, G., Mas, A. (2016) Food Microbiology 1-9 Valade, M., and Laurent, M. (2015) Le Vigneron Champenois 54-71. Funding provided by OMAFRA – U of G Partnership