Making Wine at Dixon's Jess Jones Winery

In my last article I talked about the vineyard at the Jess Jones Winery south of Dixon. There, Jones grows the nine varieties of grapes that go into his various wines.

In my next visit with Jess, we talked about the more involved and difficult part of his business – making wine from all those grapes. Wine publications often talk about grapes and vineyards, but don’t often venture into the more-important area of winemaking.

If you think that making wine is a straightforward, cut-and-dried operation – where you crush the grapes, let them ferment, produce some alcohol, and then bottle the result – read on, because the reality is much more involved. To produce good wine, one almost needs a degree in chemistry.

When Jess decided to begin making his own wine around 2004 (after having only sold his grapes to others before) he took some winemaking classes at UC Davis where some of his classmates were from the larger, prestigious wineries. The classes covered things like wine chemistry, wine filtration and clarifying wine.

Then he gradually acquired the machinery and devices to make his wine. He bought much of it from a basement winemaker “out of control” (as Jones put it) who had much more winemaking paraphernalia than an amateur vintner would need, but had left the hobby.

Jones’ first wine (some merlot and cabernet sauvignon) was made at another winery who he’d sold grapes to.

Following that, Jess began the hands-on learning period of making his own. After hearing about all the steps and ins and outs of winemaking, I can only compare the process to driving down a freeway where you make dozens of decisions concerning which lane to use, speeds, and so on. Winemaking has the equivalent of all these concerns and a couple hundred more.

So … Jess was explaining the various steps in turning raw grapes into finished, bottled wine.

First, fresh-picked grapes go into his crusher stemmer machine, which crushes the grapes but doesn’t completely pulverize them, and removes the stems and grape leaves.

From here on, grapes destined for white or blush wine – and grapes destined for red wines – take different paths.

In making white wine from white-wine grapes (or blush wine from red-wine grapes), the grapes are put into a grape press which squeezes out the juice. The skins, pulp and seeds that remain are put aside and not used further. The juice is then emptied into an open-top vat (in Jones’ case, a large plastic container holding 260 gallons) where commercial, granular wine yeast (a form of fungus) is added and fermentation begins.

The process of making red wine is more involved. Yeast is added to the mixture (called “must”) of grape juice, pulp, skins and seeds and fermentation begins and is completed. During fermentation, Jess has to repeatedly mix the solids with the liquid to prevent a “cap” or crust from forming, which would prevent the flavors and color from the solids being transferred to the wine liquid (which is what makes red wine more complex and different than white wine). After fermentation, the must is put into his wine press where the wine liquid is separated out and the solids put aside.   

Some winemakers use natural yeasts from the vineyard to ferment their wines (which is taking a chance), but Jess prefers to use commercial yeasts that offer a better bet for developing predictable, marketable wine. Fermentation usually begins within 24 hours after yeast is introduced and lasts for about “… 48 hours of almost violent fermentation … like a pot on the stove at a hard boil. It’s just churning away,” says Jess.

If the yeast used for a particular fermentation doesn’t get the job done, and fermentation stops before enough alcohol is produced, Jess will try using another strain of yeast to finish the job.

After both white and red wines have finished the initial fermentation, Jess proceeds with another fermentation, called a malolactic fermentation, using bacteria this time, to produce better-tasting lactic acid in the wines. Malolactic fermentation can take months to complete.

Next, removing solids and precipitates from both red and white wines is a challenge. The process is called clarifying or fining. Sometimes the solids fall down to the bottoms of the vats of their own accord, and other times agents are added which accomplish the task. Jess, along with some other wineries, uses powdered bentonite clay for this purpose. He also uses refrigeration (he built his own large refrigeration unit to accomplish this, powered by a wind turbine) to help remove crystals that form in his white and blush wines. If he didn’t remove them, customers might assume that the crystals are small pieces of glass!

Somewhere along in the process, filters are also used to clarify the wines. Unfortunately they are expensive and can clog up fast.

Still, it’s not uncommon to buy wine from various winemakers and find a little residue at the bottom of bottles.  

Originally, Jess aged his wines in oak barrels to impart an oak flavor but that proved to be too costly (a barrel costs around $700 and can usually only be used three times for aging before it stops contributing flavor). So now he ages wine in his 260-gallon covered vats, and uses oak chips in his vats to provide an oak flavor.

Jess’s red wines are aged two years before bottling, and his white and blush wines, one year. After bottling, they are usually drinkable after several months. He says red wines are usually consumed within five years after being bottled. White wines are usually drunk within three years.

What I’ve just described is the basic winemaking process. But just like a cook who adds spices and other things to a soup he’s making, depending on how the taste is developing, winemakers monitor their wine and add things (or even subtract things) as the process unfolds – to ensure the wine is going in the direction they want to take it.

One of the things Jess watches closely is the acidity of his wine. White wine is usually made to be more acidic than red wine. If the acidity is too low, he will add tartaric acid (made from grapes) and possibly citric acid.

Some of the things winemakers may add to wine during the fermentation stages are extra tannins (for red wines), nutrients for yeast to feed on, sugar, concentrated grape juice, water, and a number of chemicals.

The one chemical used by almost every winemaker (including Jess) early on in the winemaking process is sulfur, added in tiny amounts in the form of a sulfur compound. Its role is to kill unwanted yeasts and bacteria – allowing commercial yeasts and bacteria to be added for fermentation. But like those winemakers who let natural vineyard yeasts produce fermentation, there are winemakers who make wine without the use of sulfur. However, doing so can sometimes result in unwanted surprises.

While making his wines, Jess sometimes takes samples to be tested at a wine lab, and he also has a trusted Italian friend in the Napa Valley who performs taste tests for him.

It’s important to aim a wine toward a particular percentage of alcohol, because if the alcohol exceeds a certain limit, a wine will be taxed at a higher rate. Jess’s wines run between 12 and 14 percent alcohol, trending toward 14. However, he does produce a port wine which had extra wine alcohol added to bring the alcohol level up to approximately 20 percent. Port wines last longer than regular red wines.

When the whole process is done and over with, one ton of Jess’s grapes have resulted in approximately 150 bottles of wine. Put another way, it’s taken 13 pounds of grapes to produce one 750 milliliter bottle of wine.

Jess does his own bottling.

In recent years, many wine aficionados and critics have begun to narrowly define what a merlot or zinfandel or cabernet sauvignon should taste like, and the large winemakers have often gone along with the prevailing view – to the point where they may want their 2007, 2010 and 1012 cabernets to taste all the same – which is possible in California where the wine-friendly climate is dependable. Wine drinkers and tasters should open themselves up to the wider range of tastes that many winemakers are willing to present. That’s what the wine adventure is all about.

Next time: How the Jess Jones winery sells its wine and markets itself.