Time to make some wine! On Day 4, we brought our four fermenting bins of Rosella's out from the cold room into our fermentation room. The four days of cold soaking has really brought out some lovely citrus and feminine sweetness in the juice. Yummy!
In order to inoculate we culture up some yeast. At Kosta Browne, we predominately use a strain of Saccharomyces cerevisiae called RC212 to run our fermentations. RC212 is a Burgundy strain that works well on Pinot Noir and is known to give great color extraction - important in Pinot Noir where sometimes wines can be thin on the looks front. RC212 is also quite alcohol tolerant (can survive up to 14-16%) and heat tolerant as well (up to around 94° F) which helps in California where we have ripe fruit (and thus alcohols in the 14-15% range) and with the new wood tanks we use for some of our fermentations. The wood fermentation vats give an incredibly sexy mouth feel to the finished wine but the wood retains a lot of heat. Thus it helps to have a yeast strain that won't die on you and leave you with a "stuck" fermentation. RC212 is known to need a lot of nutrients (remember the YANC) or it will start using any sulfur compounds in the juice to create hydrogen sulfide.
To culture yeast we take dried powdered yeast from the fridge and slowly adding water we allow the yeast to wake up from their slumber. Once our yeast starts to froth we slowly add juice from the bin/tank we are inoculating until the temperature of the yeast is within 10° F of the juice temperature (since we just brought the bins out from cold soak the juice was 58° F when we inoculated) both to give the yeast some food to eat, live free and multiply, and also to make sure they don't get "shocked" by the cold temperature when we pour it into the juice.
Once the juice is inoculated we now call it the "must". We now sit back and wait and see how our little yeast babies adjust.