If you have ever toured through a wine cellar during harvest then you know it takes on an identity all its own. The fermenting grapes come alive and give off a distinct, fruity, hot smell as they transform from fruit to juice to wine.
When red grapes are harvested from the vineyards they pass through a destemming machine and then go directly into open-top fermentation tanks. The grape skins, seeds, flesh and juice are all fermenting together to extract flavor and tannins while the primary fermentation is underway. During this roughly two week period, the sugars are fermenting into alcohol and the grapes begin their process to becoming wine. The fermenting juice needs to be frequently stirred to submerge the skins as they naturally float. One way to do this is to pump wine over the top. The other way is to punch down the “cap” of grape skins with a tool that looks like a giant potato masher.
The cap:
The cap, or as the French call it “chapeau”, is grape matter that rise and settle on top of the juice. As the juice ferments into wine, carbon dioxide is released, pushing the grape skins to the top of the tank, creating a semi solid layer. The importance of breaking the cap throughout the day is to extract color and flavor from the skins. A great comparison to the process: making tea. A tea bag must be dunked and fully submerged, and then steeped for a while, to reach its full potential.
A pump over:
One way to extract all those colors and flavors is through a pump over. By using a pump and hose, we take the fermenting juice (must) from the bottom of the tanks and spray it over the top of the cap, irrigating it to keep it moist and to reintegrate the solids back into the juice.
A punch down:
Another method is called a punch down. Here at the winery we have semi- automated technology that makes doing punch downs three times a day a snap! Using a large, flat plunger, the cap is broken and pushed back down into the fermenting wine.
As the juice becomes wine, the cap gets less dense, eventually becoming liquid itself with a few seeds and skin bits left over. We’ve extracted all the flavor, aroma, and tannin from the grapes. Now, the wine can be sent to tanks and barrels for the next step of the process: aging!
