The buzz from harvest quickly extends from vineyard to winery. Being witness to the activities on the crushpad is an exciting time! Harvest interns from around the world offer energy and cultural perspective during extended hours and harvest breaks.
Material Other Than Grapes (MOG)
Once fruit reaches the winery, winemaking teams work around the clock to process it. It begins with removing all material other than grapes (MOG). This includes leaves, stems, bugs, and anything else that may have made it into the picking bins. MOG can be removed by hand or via vibrating conveyor belts that shake the MOG from the grapes.
De-Stem or Not De-Stem
The grape clusters often go through the de-stemmer to separate the tannic stems from the berries. However, some winemakers choose to keep a portion of the grape bunches in tack for whole cluster fermentation, which can add some structure to the final style of the wine. The wines are then left to begin fermentation.
Maceration Decisions
White wines are pressed so the juice runs off the skins and goes into a stainless-steel tank or barrel.
For red wines, the juice sits with the solids for a few weeks (known as maceration). A natural “cap” of all the solids—grape skins, seeds, stems, pulp—form a top of the juice, and winemaking teams have to either pump over or punch down the cap into the liquid. This prevents bacterial risk and helps to integrate the flavors. The method used will depend on the winemaker’s style and desired extraction of tannin and darkness.
Temperature & Pressing
Winemakers keep an eye on the temperature which increases as the yeast consumes the sugar and converts it into alcohol, and temperatures reach around 75°F to 89°F. The lower the fermentation temperature, the lighter in color, body, tannin, and brighter fruit. Warmer temperatures contribute to a richer color, bigger tannin, and darker fruit. When the desired dryness is achieved, the wine is pressed off the solids and put into the barrel! The solids form what is referred to as a “pomace cake”.
Blending & Stabilization Are Key
The wines then go through blending and stabilization and are left to age. Winemakers will tend to the vintage by topping off wine that evaporates, aka “the angel’s share”, to fill this headspace to avoid any bacterial spoilage and prevent oxidation or further evaporation. Small amounts of Sulfur Dioxide (SO2) can be added to avoid oxidation and inhibit the growth of bacteria and undesirable wild yeasts.
A Second Fermentation for Sparkling Wine
Sparkling wines have a different process, where wines have dissolved into them carbon dioxide achieved during a second fermentation in the bottle. This occurs by the addition of a yeast and sugar mixture which produces carbon dioxide. This second fermentation occurring in a capped bottle traps the CO2 and it dissolves into the wine. The end result is a sparkling wine.
If you visit Anderson Valley wine country during the winemaking process, ask questions and inquire about tours. Many wineries, especially the smaller ones, invite the curiosity and are happy to take you behind the scenes and talk about the process!
Some wineries even offer barrel sampling throughout the year to experience how the young wines are developing. In July, several wineries provide a weekend of barrel tasting in Anderson Valley and welcome the chance to teach connoisseurs about current and past vintages. Visit AVWINES.com to help plan a visit and learn more!
~ Courtney DeGraff, Executive Director of the Anderson Valley Winegrowers
