We’ve entered the early stages of veraison, as our Ron Rubin Winery Estate Pinot Noir berries begin to turn from green to purple. This is a significant milestone each year and gives us a rough idea of when harvest will begin. Compared to 2017, onset of veraison is seven days later this year. Therefore, we’re anticipating the first day of harvest to also occur about seven days later. We still have a lot of summer days ahead of us, so our calendar remains fluid. A spell of hot weather, or unusually persistent fog, can dramatically shift that first picking date forward or backward.
LAST MONTH’S MENTION ABOUT YEAST AND NUTRIENTS
As I touched on yeasts used in last month’s “Winemaker’s Notes,” let’s explore more, as promised. At Ron Rubin Winery, we use some very specialized microbes. Most of the time, we’re introducing specific strains at key points in wine production.
OUR MICROSCOPIC WINEMAKING HELPERS
The ultimate quality and character of wine, made with modern techniques, is most certainly driven by the excellence of the grapes. Superior characteristics should always provide the dominant attributes that define fine wine. We can also make a significant impact by the choices we make for barrels, production techniques, and yeast.
Why use these cultured microbes? After all, it’s not absolutely necessary to use specialty yeast and bacterial strains in our fermenters. Grape juice can be turned into wine quite effectively, with the help of native microbes found throughout our environment. As a winemaker, my challenge is to direct the action, by providing the right conditions for the juice to become a truly enjoyable wine!
Depending on the wine being produced, we may introduce variety-specific yeast strains within 24-hours of picking. Other grape varieties will be allowed to “cold soak” for five days or more, to extract color and flavor from the grape skins. After the cold soak, the fermenter is inoculated with our choice of yeast.
The range of yeasts available is impressive. Most are strains of two yeast species; Saccharomyces cerevisiae or Saccharomyces byanus, along with hybrids of the two. They’re very similar to baker’s yeast but are selected for traits that are best suited to ferment grape juice into wine.
Here are a few yeast strains we use at Ron Rubin Winery:
QA23 is a yeast selected for aromatic white wines, like Sauvignon Blanc. We find this yeast to be well-suited to our unoaked, tank fermented wines. It easily handles the low oxygen environment and low fermentation temperatures.
3001 is a yeast selected for fermentation, in the Côte de Nuits of Burgundy. After the “cold soak” we employ before fermenting, this yeast shows good fermentation strength.
D47 is an ideal yeast for barrel-fermented Chardonnay. It has a quick initiation of fermentation and lots of polysaccharide creation, resulting in a richer mouthfeel.
When we receive freshly picked grapes from our vineyards, the process of fermentation begins very rapidly, unless we chill the grapes or juice. We have a few techniques, which buy us time and allow some measure of control. These are critical tactics that allow a preferred yeast to become dominant, in the fermenter.
Bird and insect control
Nothing will initiate spoilage better than broken berries on the vine, so we employ bird nets and scare devices; like foil ribbon and audio speakers that generate raptor calls, to keep the birds away from our crops.
If insect damage is spotted (typically from yellow jackets), any damaged clusters will be removed before picking, and then “sorted out” on the crush pad.
Overnight temperatures in the Russian River Valley will consistently drop into the upper 40s and low 50s, during August and September. This natural refrigeration of the grapes slows down fermentation.
Tiny additions of sulfur dioxide (“sulfites”) will reduce populations of unwanted yeast and bacteria naturally occurring on the grapes. We can then re-populate the fermenter with chosen strains.
BOTTLING ESTATE WINES
Bottling our small lot, estate and vineyard designated wines, in late July and early August, is another yearly milestone. We find this very exciting, as the hard work of the previous 12 months is now safely tucked into each bottle. We can now fully devote ourselves to the upcoming harvest.
Speaking of harvest, our seasonal winemaking “interns” have been hired. We’ve assembled a good crew. Over the next few weeks, we look forward to engaging them in the enthusiasm of Crush 2018!