Harvest season is well under way here in Napa Valley. Today I am going to describe the journey of some of our Chardonnay grapes. In California, several winemaking methods can be used to obtain different styles like dry or sweet, including stainless-steel fermented and aged or barrel fermented. Last week, I welcomed a batch of grapes which will become a part of WineShop At Home’s future 2014 brands.
White grapes are harvested at their optimal ripeness and quickly brought to the winery for processing. The degree Brix (symbol °Bx) quantifies the amount of sugar, the dominant compound in grape juice, which is measured by using a refractometer. Many other soluble substances such as salts, acids and tannins, will also play a role.
WHOLE CLUSTER PRESSING allows a gentle pressure to be applied to the grapes. Over two to three hours, the grapes are being squeezed up to two bars in pressure. This process prevents the harsh tannins from skins, seeds and stems to come into contact with the grape juice called “must.” This term describes freshly pressed grape juice without skins, stems and seeds.
A berry sliced in half, can give an accurate location of all the grape juice’s main constituents. Water and acid are primarily found in the pulp. Tannins are concentrated in the skin and the seeds. Therefore, the pressing process of the berries allows for a separation of these compounds avoiding any excessive bitterness in the fresh squeezed must.
The first part of the cycle yields a considerable amount of juice within the first 40 minutes; this must, called free-run, is typically of a higher quality than the press juice obtained during the rest of the cycle. Sometimes wineries separate these juices and ferment them separately as well. Pressed juice can represent up to 30% of the total juice volume from the grape. This harvest season, I decided to keep all of the juice together to create a richer, more structured final wine. WineShop At Home produces several styles of wines therefore I need to have several lots to work with at my disposal to blend for our future 2014 wines. The must starts its fermentation in a tank. Over the next five to six days, the sugars will be transformed by the yeast into alcohol and carbon dioxide.
After this first stage of the process, the winemaker once again starts to organize his puzzle pieces in order to seamlessly assemble them later on. Two main choices for white wines are available at this stage:
STAINLESS-STEEL FERMENTATION can be used for some Sauvignon Blanc, Riesling and Chardonnay to retain their crisp and fruity quality.
BARREL FERMENTATION, also used for Sauvignon Blanc, Semillon and Chardonnay, takes place in a 60 gallon oak cask, usually giving more complexity and flavors to the final wine.
At this stage, the must is turning into wine but is still in a rough form, full of lees and carbon dioxide. The winemaker will select and grade his wines in about one to two months. Some of them will spend time in tanks or in barrels going through the secondary fermentation: the Malo-lactic Fermentation.
It’s always an exciting moment to witness the birth of a vintage. The time has come now to carefully nurture, care and guide this newcomer to the path of greatness.
Stay tuned for next month’s article, Part 2 of “The Birth of the Almighty Chardonnay: From Malolactic Fermentation to Ageing,” where I’ll give you an update on how this vintage is doing and walk you through another part of the winemaking process.