[By Richard Sheppard in Calistoga, California] I live just over an hour’s drive north of the Golden Gate Bridge, in the Sonoma County wine country. At this time of year, golden leafed vineyards blanket the rolling hillsides and you can smell the aroma of fermenting grape juice for miles.
With all the grapes picked and hauled off to wineries, the time consuming process of turning grapes into wine begins. (You can read my post on the grape harvest here: Spirits of the Vine) My long time winemaker friend, Vince Tofanelli allowed me to watch him in action.
Waaaah, waaaah, waaaah! The pump complains as grapes head past us, and up the conveyor. Sticky Zinfandel juice and its skins coat our hands as we sort out raisins, leaves, and the occasional black rot. I concentrate on the sweet, floral smell to distract myself from the de-stemmer’s pulsating wail, like a low-pitched foghorn.
Vince leans over to talk above the noise, “Once the grapes are crushed, I’ll do a cold soak. Then I’ll add a touch of sulfite to accentuate and preserve taste and aromas, and a cultured yeast to consume sugar. The sugar converts to alcohol and the CO2 escapes into the atmosphere. Most of wine’s flavor, tannins, and virtually all of its color comes from contact with the skins during fermentation.”
Once the grapes have been passed through the de-stemer, they are conveyed to a large stainless steel tank to ferment. Stepping away from the sorting table, I notice a sweet, effervescent aroma flowing out of the cellar: fermentation. The scent reminds me of doing pump-overs so long ago when I worked a fall harvest at Mondavi Winery.
Once the grapes are in the tank, the juice seeps out, leaving the skins to float up and form a cap. For uniform fermentation, the skins must be mixed back into the juice by using either the pump-over or punch-down method.
Vince uses an electric pump that sucks juice through a hose from the bottom of the tank and up to a sprinkler device just above it. As the juice is repeatedly sprinkled over the skin-cap, contact with the skins ensures maximum flavor and color extraction. Cellar workers repeat the process two or three times a day for about a week until fermentation is complete.
The alternative, and more old world method, is the punch-down. In this case, a long pole with a flat metal attachment at the end is used to manually push the skins into the fermenting juice. This method requires a heavy amount of labor and can be done only in small tanks and tubs. I used both methods while working at Robert Mondavi, with punchdowns reserved for Robert’s prized Reserve Pinot.
I’ll never forget the voice of the foreman who trained me. “Whatever you do don’t fall in. If no one’s around to pull you out, you’re as good as dead.” The escaping carbon dioxide leaves no room for oxygen in the tank. As careful as I was while doing punchdowns, I did slip once, heart beating faster than a racehorse at the finish line.
With all Vince’s grapes now in the tank fermenting, our job is done. Let the pump-overs begin!
Pressing Time (one week later)
When I arrive at Envy Winery, Vince is in full action mode, issuing instructions as cellar workers scramble, preparing to press his wine. Today’s activities are to drain the fermented Zin juice from one tank to another, leaving behind only the grape solids, then shovel this remaining pomace onto a conveyor that lifts it into a basket press, where an expandable bladder presses out the remaining juice.
Vince says, “Once pressing is complete, I’ll add a malolactic bacteria culture to start secondary fermentation.”
An alarm sounds, the tank rotates, then fills up with air. When the right pressure is reached, wine juice seeps from the holes in the steel barrel and runs into a holding tray below. From there the wine is pumped into the new tank. The machine hisses, rotates, and then re-inflates. The flow of wine picks up, pouring out through the drum holes of the press and into the tray. We put our glass in the flow to catch some wine, then taste.
The wine is cloudy and bright pink, and tastes of fresh picked raspberries. The alcohol is noticeable and little sweetness remains.
Vince says, “There’s still a little residual sugar left in the wine. That’ll cause the wine to spontaneously ferment in the barrel. Primary fermentation converts the sugars to alcohol. During secondary fermentation, malolactic bacteria feeds on the acidity in the wine, rather than the sugar, and converts the acid into lactic acid or lactose. That’s what gives some wines an apple aroma. Cold storage stops secondary fermentation, or it can be encouraged by warming the wine a bit. I also add sulfites during fermentation to help stabilize the wine.”
Vince dumps his wine on the ground, shaking out the glass, and encourages me to do the same.
The press deflates, rotates, flops around like an unbalanced washing machine, then re-inflates. The second pressing begins, and we hold up our glasses to catch another taste.
“Nice aromatics. Wild cherry cough drops.” Vince says. “Maybe even black plum. Which usually shows through in the finished wine.”
Where earlier I detected fresh raspberries, now I’m tasting cherries and cranberries. The wine also appears less cloudy.
“Lees are what’s clouding the wine at this point.” Vince says anticipating my question as I hold the glass up to the light.
Leaving the wine on dead yeast cells and other silt doesn’t sound appetizing, but the process adds body, complexity, and character. Vince will age the wine sur lee for four or five months to add this mouthfeel. The process requires finesse to avoid off-flavors like rubber, or sometimes even a band-aid smell.
At the third pressing, we refill our glasses. Greater clarity, cherry aromas, stronger tannins, and a tangy finish. The tannins remind me of chewing a grape beyond its sweetness to discover the tannins contained in the skins and seeds.
“We’ll stop here,” Vince tells me. “That’s about as much good juice as we can squeeze out of the skins. Tomorrow we’ll rack the wine into barrels.”
Racking into Barrels
The following day I return to Envy winery just in time to see Vince with his nose in a barrel hole.
Vince calls to me, “Come on over and smell the barrel.” Other than the obvious smells of wine and oak, my nose picks up maple and brown sugar characteristics. These are some of the complexities the oak will add to the wine. “We’re looking for any bad odors in the barrel, like a swampy or vinegar smell.” Once Vince gives the okay, the workers fill the barrel with the fresh new vintage of Zinfandel. This process of racking the wine from tank to barrel leaves the lees behind in the tank, and at the same time clarifies the wine, softening the tannins, and enhancing its aromatics.
Vince pulls a plug, called a bung, from a barrel. “Put your ear up to the hole and listen.” When I do, he tells me, “That fizzy sound is telling us that primary fermentation is still going on. When secondary fermentation is happening, it’ll be more of a snap, crackle, and pop.”
It’s at this time, I realize one reason Vince’s wine is so good. He not only grows excellent fruit, but has complete control from vineyard to glass. He understands the special needs of the wine through each stage of its process. From here Vince tells me the wine will age up to two years before being blended, then bottled.