Chateau Montelena in Napa Valley has undertaken a major renovation of its cellar after discovering that both the winery and its wines have been contaminated by TCA (2,4,6 trichloranisole), a chemical compound responsible for the off-flavors in corky wines.
Winemaker Bo Barrett said Chateau Montelena, best known for its Cabernet Sauvignons and Chardonnays, began testing its facility for a possible TCA problem in 2002. Recent vintages had repeatedly shown a musty character, he said, which the winery believed came from TCA-tainted corks.
But after a Wine Spectator report in 2002 detailed how Beaulieu Vineyard's red-wine cellar had been tainted by TCA, Barrett said, Chateau Montelena hired a leading wine laboratory to test its cellar, equipment and wines. ETS Laboratories, based in St. Helena, Calif., determined the presence of TCA. "Then we realized it wasn't the cork thing," Barrett said.
Barrett admitted that it is likely that TCA was part of the winery's "house style" and that it was present in most of the wines at a low level. TCA "may have been one of the components of our wines dating back to the 1970s," he said, "especially when the wines weren't fruity."
TCA can form when mold interacts with chlorine and phenolic compounds in products such as wood, cardboard or cork; if it's not detected, it can spread throughout a winery, into barrels and wines. While TCA may impart a musty or moldy character to wines, or simply mute their fruit character, it is not a health threat.
Chateau Montelena produces 40,000 cases a year, and the Montelena Estate Cabernet bottling sells for $125 a bottle. Barrett declined to say how many of the wines had been tested by ETS. But he said early tests showed some of the wines had TCA levels near 4 parts per trillion (ppt), and the winery has been trying to bring the level down to 1.4 ppt or less in its latest vintages.
There is no industry-wide standard for an acceptable level of TCA in wines, and people's ability to detect TCA varies greatly. The 1.4 ppt level is considered below the threshold of perception for most tasters, though sensitive individuals can detect even lower concentrations.
Barrett acknowledged that the winery was battling TCA after Wine Spectator showed him lab tests done this summer that indicated some Chateau Montelena Cabernets, including the 2001 and 1997 Montelena Estate bottlings, had low levels of TCA.
Symptoms of TCA taint were first detected in blind tastings in the magazine's Napa office. Many Chateau Montelena wines, from the 1997 vintage to a 2003 barrel sample, showed either wet cement and chalky, chlorinelike flavors or other off-characteristics associated with TCA. So Wine Spectator had ETS Laboratories test seven Montelena Cabernet samples; five of them had levels of TCA ranging from 1.1 ppt to 1.7 ppt, and two had less than 1 ppt.
The ETS test results also found that all seven of the samples had low levels of tetrachloroanisole and pentachloroanisole, compounds which are similar to TCA and are associated with wood treated with certain preservatives; such chemically treated wood has been linked to taint problems in many European cellars.
Chateau Montelena had already begun overhauling its old cellar immediately after ETS confirmed the existence of TCA, though Barrett declined to estimate how much the cleanup has cost. He said the winery had replaced all suspect barrels and old cooperage, along with all wood barrel racks that had come in contact with chlorine in cleaning agents. The winery's interior walls were hand-scraped to remove accumulations, and wood catwalks and ladders were replaced with aluminum. The winery has been replacing oak fermentation and storage tanks, changing out 17,000 gallons of tanks in 2003 and 2004, he said.
Keeping Montelena's cellar clean has been a challenge, because the building is old, dating to the 1870s, and chlorine-based products had been used for years to clean the interior. Barrett said the winery had a "cellar funk" to it, and over the decades, he and his staff have battled microbial issues related to Brettanomyces, a spoilage yeast, along with bad corks.
Montelena is the latest California winery to have its wines marked by TCA. BV's tainted red wines dated to 1997 and may have involved several hundred-thousand cases; the winery has since revamped its entire cellar. Wine Spectator also discovered TCA contamination at Hanzell, a Chardonnay and Pinot Noir specialist in Sonoma, and Gallo of Sonoma, one of Sonoma's largest wineries. Hanzell has since opened new wine production and storage areas. And in an ongoing process, Gallo has made changes at its Dry Creek Valley facility that it reports have reduced TCA levels in the cellar and the wines so far.