The choice of yeast strain used for S. blanc production has a big influence on the final aroma profile and wine quality. So depending on personal style, regional style, country style, styles your consumers prefer, style your grape quality allows you to produce – different winemakers use different yeasts to aid them in achieving this desired style. I decided to ask a few winemakers to share their fermentation secrets with me.
Erika Obermeyer, female winemaker of the year 2008 in South Africa and head of the South African Sauvignon blanc Interest Group has been very successful over the past few years with her Graham Beck Sauvignon blanc. Erika gets her grapes from seven different vineyards, all classified as coastal, with influence from the Atlantic Ocean. She starts tasting the grapes at 16°Brix and picks on flavour. Each vineyard delivers a specific aroma profile in the final blend. Harvest starts in the last week in January and continues for four weeks depending on the location of the vineyard. 
Erika uses the Laffort skin contact enzyme for 5 hours at 8 – 12°C. She has an additional 7 – 13 hours of skin contact but at very low temperatures where the enzyme is obviously not active anymore. After pressing she settles for three days and achieves a juice clarity of 20 NTU this way. This, off course, is way too clear for fermentation and she therefore includes some of the fine lees when racking the juice. Her final juice clarity for fermentation is usually between 50 – 80 NTU, which is a typical NTU for new world wine fermentations.
Now for the juicy part: Erika uses 50% Anchor VIN 7, 40% Laffort VL3 and 10% Anchor Alchemy II for fermentation in different tanks (not co-inoculation). The vineyard the grapes derive from determine the yeast used. She uses Lallemand Fermaid K as a complete yeast nutrient for fermentation.
  • VIN 7 is used for its production of gooseberry, passion fruit and grapefruit aromas. Fermentation is conducted between 11 – 14°C at a sugar drop of about 1 – 2°Brix per day.
  • VL3 is used for its production of similar type aromas as well as more of a green fig contribution. It also produces very good mouthfeel and “respects” the pyrazines / green aromas. It is fermented at slightly warmer fermentation temperatures of 13 – 15°C.
  • Alchemy II has a similar profile to VIN 7 but with more esters – thus a “sweeter” profile. Erika uses Alchemy on the vineyard blocks she feels need a little bit of an “ester” boost.
 The wines are kept on their gross lees, which is stirred twice a week. The final blend is kept on the fine lees until stabilisation before bottling. The first release of the wine is in June of the same year. Bottling is done on demand. The rest of the wine remaining in the cellar is kept at about 4 – 7°C.