What's Your TCA Threshold?

Vinquiry tests sensitivity levels down to 1 part per trillion

by Jim Gordon
What's Your TCA Threshold?
Sue Langstaff, sensory scientist at Vinquiry lab in Napa, Calif.
Napa, Calif. -- Wineries that want to know which of their employees will make the best cork quality control technicians will have several opportunities this year to find out. Vinquiry, the analytical consulting and supplies firm, has announced the first three in a series of trichloroanisole (TCA) threshold testing sessions available to industry members at $75 per person.

The first two sessions, Jan. 17 and Feb. 26, will be held in Napa, and other sessions will be announced later. The first TCA threshold testing to be done at Vinquiry's Paso Robles lab is set for May 22. The testing takes 30 minutes, and it identifies a participant's lowest level sensory threshold for TCA, said Sue Langstaff, a sensory scientist for Vinquiry who supervises the testing.

Langstaff told Wines & Vines that the majority of the people tested during the first two years of the Vinquiry program were employees of cork companies, winery lab techs, and winery sales and hospitality staffers who need to positively identify corked bottles in the tasting room or on sales calls. She recalled only one person from the restaurant industry who has taken advantage of the testing, but she said Vinquiry would welcome more.

To register, visit vinquiry.com and click on News & Events to download a PDF registration form. Registration can also be handled by phoning (707) 838-6312. Testing appointments are limited, so it's best to register early.

What's Your TCA Threshold?
Sample glasses of white wine laced with minute quantities of TCA.
"A lot of the people we test already know the smell of TCA, and we're just seeing how low they go," Langstaff said. The testing level starts at 10 ppt, a level at which a significant minority of those tested did not detect TCA at all. But others' sensitivity goes as low as 1 ppt.

She said that it's important to remember that each person has a range of sensitivity which varies from day to day, by time of day, and according to environmental conditions, so a number of people have tested multiple times to more accurately define their ranges. "I think some of them treat it like a contest," she said, "each time trying to lower their threshold."

"I'm not going to mention names, but we're noticing that lot of the people from the cork companies are not noticing the TCA as well as the winery personnel," Langstaff said. "People who do this every day at the winery are very good, often at 1-2 ppt, but on an off day they can't detect it at 6 ppt."
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