Practical Winery
58-D Paul Drive, San Rafael, CA 94903-2054
phone:415/479-5819 · fax:415/492-9325
email: Office@practicalwinery.com

January/February 2001


Robert Mondavi Winery: Creating a Winery to Match a Vineyard

Carol Caldwell-Ewart

What do you do when you have a 550-acre vineyard that you believe produces the best Bordeaux varietal wine grapes in California and maybe the world?

If you’re Robert Mondavi Winery (RMW), you re-invent the way you make Cabernet Sauvignon and spend $27 million to remodel the 34-year-old winery you’ll be making it in. Then you dedicate a new multi-level building to the production of about 225,000 gallons of Cabernet Sauvignon annually and name the resulting winery facility To Kalon, which is Greek for “highest quality” or “greatest beauty.”

“The To Kalon estate vineyard is a star,” declares Genevieve Janssens, director of winemaking at RMW, Oakville, CA. “It is one of the most extraordinary vineyards on earth.” The Napa Valley vineyard on the Oakville bench was first planted by H.W. Crabb in the late 1800s. It has gravelly loam on the slopes with more alluvial, loam, and clay soils towards the valley floor.

Robert Mondavi began buying acreage in Oakville in 1966 and now owns a total of 770 acres, of which
655 are planted. Of those, 105 acres are part of Opus One, RMW’s joint venture with Chateau Mouton-Rothschild. The rest will eventually provide the To Kalon cellar with 900 tons of fruit annually.

To Kalon will produce RMW Reserve Cabernet Sauvignon (current release 1997; 20,000 cases; suggested retail [SRP]: $120 per bottle), To Kalon Vineyard Cabernet Sauvignon (1997; 1,000 cases; SRP: $150), Oakville District Cabernet Sauvignon (1997; 14,000 cases; SRP: $50), and some additional To Kalon vineyard designates when grape sourcing allows.

Though the 2000 vintage was the first to be processed in the remodeled production facility, much of the To Kalon Vineyard is still in redevelopment. About 460 acres have been replanted in the last 10 years due to phylloxera at a cost of about $14.5 million. Many are in high-density blocks as closely spaced as 4x4 feet (2,723 vines per acre). These blocks are just achieving the quality that the winery seeks for its To Kalon wines.

Until more To Kalon fruit is available, only a limited amount of the To Kalon Vineyard Cabernet Sauvignon will be produced (1,000 to 1,500 cases from the 2000 vintage). In the meantime, and in addition to the RMW Reserve and Oakville District Cabernet Sauvignons, the winery will use this facility to produce a portion of its Stags Leap District Cabernet Sauvignon, as well as district Merlots and other wines.
Renovation package
Remodeling of the original winery — to be completed in 2001 — has resulted in a new gravity-flow, red-wine production facility with a footprint of more than 20,000 square feet. A three-level structure eliminates the need to pump must from the crusher to the oak fermentor, sluice pomace into the press, or pump wine into barrels.

Grapes are harvested into 35-pound lug boxes and transported to the winery. Elevators carry them up to the mezzanine level where they are hand-sorted, destemmed, and lightly crushed into 16-ton (5,000 gallon), French oak fermentation tanks for primary fermentation, followed by extended skin contact of 35 days or more at warm temperatures of 81° to 83°F.

After primary fermentation and warm extended maceration, fermented grapes go to one of the four five-ton Marzola basket presses, where they are pressed. The wine is transferred to French oak barrels in the first-year, underground barrel cellar directly beneath the fermentation room. The cellar holds 1,200 barrels one-level high for unrestricted access.
A return to tradition
Thirty years ago, Robert Mondavi Winery was a pioneer in the use of stainless steel for cold fermentation of white wines and clean fermentation of red wines. However, for the past several years, the winery has been experimenting with oak fermentation, a traditional method that is returning to favor in Europe.

Timothy Mondavi, winegrower and managing director of RMW, reports that “Oak fermentation imparts complexity, richness of texture, intensity, and depth of color, which is ideal for our reserve and district red wines, and particularly enhances the fruit from our To Kalon Vineyard.”

Fifty-six 16-ton-capacity, oak fermentors were installed in June 2000 by a team of French craftsmen from Tonnellerie Taransaud together with Gene Nelsen and his team of American coopers from Al Bellagio Wood Tank Co. (Healdsburg, CA). After tank construction at the cooperage in Cognac, each stave was numbered, and the tanks were disassembled and shipped to the winery for reassembly. (Taransaud has also recently provided oak fermentors to Haras de Pirque in Chile, Chateaux Pontet Canet, Canon La Gaffeliére, La Monodotte, and Montrose in Bordeaux, and Harlan Estate in the Napa Valley).

Nearly 11 feet tall, the tanks are almost 10 feet in diameter at their widest point and 8-feet, 8-inches across at the top. The top man-door is one meter in diameter, and there is an external progressive opening in the bottom head to allow removal of pomace; it is stainless steel, outward opening, and 18 inches in diameter. There is an 18-inch diameter side gate. Inside the tanks, a moveable sprinkler device provides pumpover during fermentation.

Thirty-two of the tanks each have one dimpled stainless steel cooling plate with about 45 square feet of surface area mounted off-center four or five feet above the tank floor, situating them just below the bottom of the cap when the tank is filled. The plates are plumbed through the tank walls and circulate cool glycol during fermentation.
Making To Kalon wines
Assistant Winemaker Richard Sowalsky heads the Cabernet Sauvignon, Merlot, and Sauvignon Blanc winemaking programs at RMW, including the To Kalon program. He says their winemaking goal is to achieve wines demonstrating a balance between concentration and elegance and contends that oak fermentation and warm extended maceration are the perfect match for To Kalon fruit.

“When simple fruit expression is most prominent and tannins aren’t hard, oak fermentation isn’t necessary. But grapes with big, firm tannins, as To Kalon fruit has, clearly benefit from this treatment. The tannins soften during extended warm maceration.

“In the best To Kalon fruit, the tannins are typically comprised of monomers and short-chain polymers, which can give the young wine an aggressive mouthfeel. If we can get oxygen into the must during pumpover, it stabilizes color and softens the mouthfeel. This is a very reactive time, and the phenolics are typically the most oxygen-reactive component of the must, so this process does not oxidize the less reactive aromatic compounds.”

Extended maceration (35 days on average) at warm temperatures (83°F) enhances further extraction of tannin substrates from the grape skins while hastening the reactions of polymerization. This results in substantial yet approachable wines with enhanced color stability. The winemakers determine the length of skin contact time for each wine lot by tasting the young, macerating wines.

Sowalsky reports that the warm maceration regime was arrived at over a number of vintages and extensive experimentation, particularly with regard to tannin development and color stability. “The peak fermentation temperature is 33°C (91.4°F); the majority of fermentation is carried out at 31°C (87.8°F); and our desired maceration temperature is 28°C (82.4°F). (See Tables I and II).
“Warmth from fermentation, combined with the insulating effects of the oak tanks and warming of the fermentation cellar, maintains the 28°C temperature we wish to achieve during maceration.”
In 2000, the best of the Oakville wines did undergo oak fermentation and warm extended maceration. Janssens and Sowalsky believe that this treatment would also be appropriate for some of RMW’s Carneros and Stags Leap district wines.

In the earlier To Kalon Vineyard Cabernet Sauvignon vintages, Sowalsky reports that, while all lots had extended warm maceration, the 1997 received no oak fermentation, the 1998 was 58.7% oak fermented, and the 1999 was 81% oak fermented.

The To Kalon philosophy is to allow fermentation to take place naturally, initiated by native yeast. Sowalsky admits that’s not always possible. “I base the decision on vineyard quality, grape maturity, must nutritional status, and pH. In 1999, grapes were heat-stressed, and we couldn’t risk native yeast.”
“If natural malolactic fermentation (MLF) doesn’t occur under the cap,” he adds, “it will finish in the barrels.”


The heavy press wine (1.0 to 2.0 bar inflation) is separated to be fined following MLF and metered into the final blend, but Sowalsky and the cellar crew taste the light press wine (0.6 to 1.0 bar inflation) the next day, and it usually goes back into the drain wine.

Wine going into barrel in November or December is typically blended the following June, then fined with three to seven fresh egg whites per barrel in November (one year after barreling).

Barrel ageing is in 85% new French oak. Wines are barrel aged 18 months, bottled unfiltered, and released after a minimum of 12 months as bottle ageing.

Janssens says another important element of the To Kalon winemaking style is varied grape maturity. “We pick according to the profile of the vineyard, and it’s a big range,” she explains. “If we have a vineyard yielding fruity grapes with a low level of tannins, we pick early to avoid tired fruit with prune, raisin, or dried fruit flavors. Others are picked with ripe mature tannins.”

Sowalsky adds, “As the grapes mature, the tannins can go up and up, but the fruit peaks. We don’t want the fruit to be jammy.”

The yield goal for wine from To Kalon grapes is 165 gallons per ton.

Though RMW may not be the first winery to take a new look at oak fermentation or to opt to go with warm extended maceration, its commitment to these winemaking techniques is certainly one of the largest. Much as Robert Mondavi Winery was a leader in the use of stainless steel tanks, the winery may again be setting a standard for production of Bordeaux-style red wine in the future.