By Khalida Sarwari
Don Arnold takes a seat at a long conference table, scans the four lidded, half-full glasses in front of him and waits. Across the table from him, Jinyu Xu does the same.
Susan Willis then rushes in and sits next to Arnold. Once Amy Lazzini arrives, they can start. She does, and minutes later it’s on.
They quietly begin sniffing, swirling and taking small sips from the cups in front of them and jotting down their observations on a white sheet of paper. They throw out descriptions such as “acidic” and “sweet.”
No, they’re not in Napa, and they’re not sipping wine. They are sommeliers—of water.
Ever had a glass of cold water on a sultry summer day that really hit the spot? These folks are the ones to thank.
While the Santa Clara Valley Water District uses high-tech equipment to analyze the quality of the water it sends through its system to retailers who deliver it to residents and businesses, it relies on an even more powerful machine: the human palate. As members of the Santa Clara Valley Water District’s flavor profile analysis panel, Arnold and gang can distinguish different taste and odor compounds in water.
Arnold, a biologist, has been on the panel for the last two years of his 15-year tenure at the district. His colleague, Xu, is an assistant engineer in the district’s water quality unit with one year’s experience on the panel. Lazzini, a microbiologist, has been with the district more than two years and has been a taster for 1 1/2 years. Willis is the trainee among them, with two months experience on the panel, and is a water quality superintendent at the San Jose Water Company.
The veteran in the group is Johanna Castro, a senior engineer who has been with the district almost 18 years and has just as many years of tasting experience. She leads the Sept. 6 session inside a lab in San Jose, which has an isolated ventilation system so as not to draw in smells from other places that could interfere with the tasting. The room has a high window and two whiteboards and closely resembles a classroom. The space is supposed to be free of odors at all times, which means panelists are advised against wearing perfume, cologne, lotions or scents of any kind. Still, the distinctly pungent smell of the dry erasable marker Castro uses to mark the panelists’ feedback on a chart on the whiteboard wafts from the front of the room to the back.
The group meets every Tuesday from May to October, when algae blooms in the district’s water supply tend to be higher because of the warm weather, resulting in flavor compounds that create a variety of smells and tastes in the water. The rest of the year, they meet every other Tuesday. Panel members rotate but are assigned tastings regularly to keep their palates finely tuned. There must be at least four members present at each session for the tasting to take place.
Because each panelist has a different degree of sensitivity to flavors and aromas, the group relies on the combination of their palates to help pick up on faint flavors and aromas.
“In my experience, the best panel members have been people who do a lot of wine tasting because they’ve been able to develop their palate,” said Castro, a wine enthusiast herself who noted she doesn’t drink wine “as often as I would like to.”
On tasting day, the panelists are advised to avoid foods that are overly spicy or leave residual tastes such as onions or garlic, and are asked not to eat or drink anything except water in the two hours prior to the meeting.
Most sessions last no longer than half an hour, and the tasting process is fairly straightforward. Each panelist gets one glass of distilled or purified water to have something completely flavorless and odorless to compare their water samples against. They also each get four glasses of water, three of which contain water from the district’s treatment plants in Santa Teresa, Rinconada and Penitencia. The fourth is a raw, or untreated, water sample from the Sacramento-San Joaquin Delta, which is meant to be smelled only.
It’s a blind taste test, so the panelists don’t know the origin of the water samples, save for the raw sample. Someone recalls a former member who once accidentally took a sip of the raw water: “He’s probably scarred for life.”
The samples are warmed to release any odor or taste compounds, similar to what the customer might be receiving. The tasters begin by sniffing the distilled water, then proceeding to the first sample, sniffing and jotting down notes until they reach the fourth glass, returning to the distilled water after each sample to refresh their memories and clean their palates.
Then it’s on to tasting the samples, repeating the same pattern. After each sip, the members mark down whether the water was musty, grassy, fishy, sweet, bitter or medicinal, for example, as well as the intensity of the taste and even the mouth-feel of the water. They use a rating system that starts at ‘T’ for trace, which is just barely noticeable, and increases by increments of one-half, all the way up to 3, which is unpalatable. Because they seldom detect anything in the 2.5-3 range, they’ve erased it from the whiteboard altogether, Castro said.
After the tasting, the panelists empty their cups into a water jug in the center of the table and submit their observations to Castro.
What’s next for the jug of water? “It’s going down the drain,” Castro says, but Arnold quickly cuts in: “No, it’s going on plants because we don’t waste water.”
It’s those white sheets with the panelists’ feedback that really matter, however. Castro collects them, types them up in an email and sends them off to lab supervisors at the three plants. They, in turn, assess the panelists’ observations to gauge the effectiveness of their treatment, said Lei Hong, a water quality engineer at the district who led the program for three years. The data is also sent to the district’s own water quality unit.
“We’ll review the results and discuss together to see if there’s anything we can do or any issues we need to troubleshoot,” Hong said. “Then we’ll do some evaluation. We’ll work together to adjust the treatment process. It’s an ongoing monitoring, especially during the high season.”
The tasting process begs the question: Is there an ideal taste that the sommeliers are trying to look for? Not so much, said Castro. “Ideally you want no taste at all,” she said. “No taste or odor.”
A major public misconception is that if water tastes bad, it must be harmful, Castro said. In June, a Saratoga resident launched a Change.org petition calling on the San Jose Water Company to provide clean drinking water after some residents started complaining about “a strong petroleum odor” in their drinking water.
Saratoga residents were not the only ones concerned. Customers in Campbell, Los Gatos and Monte Sereno also reported a slight, dissipating “earthy” odor in their tapwater.
Saratoga city officials assured residents the water had been tested and deemed safe for consumption after meeting all drinking water standards. They said an algae bloom in the water supply was to blame; the hot summer sun warms up the water in reservoirs and delta, increasing the chance of algae blooms that can leave behind flavor compounds that create a variety of smells and tastes in the water. While the treatment process usually removes the algae and makes the water safe to drink, it doesn’t always remove the lingering odor.
“Most of the tasting odors that we deal with are generated by algae,” Castro said. “This year we’ve had a few inquiries about whether the water is toxic. [But] toxins don’t produce a taste in water. Compounds that do are not toxic.”
The “earthy” scent residents smelled was likely caused by geosmin, an algae compound that gives water an earthy or musty flavor, according to district spokeswoman Colleen Valles. Panelists have been monitoring the intensity of the compound and helping the district mix water from different sources to mitigate the smell and taste, she said.
Hong attributed the issue to the San Luis Reservoir experiencing an especially extensive algae bloom this year. The reservoir, which is the main water source for the Santa Teresa and Rinconada plants, typically gets one week of high geosmin levels, but this year it lasted a month, Hong said.
“In order to enhance the tasting water, we use ozone and hydrogen peroxide to remove” the geosmin, she said. “We were able to achieve 90 percent removal successfully. Sometimes we can achieve 95 percent. Above that, some sensitive folks might detect it.”
The Santa Teresa and Penitencia water plants started using ozone in 2006. Eventually, the same technique will be applied to the Rinconada plant, the oldest of the district’s three plants and the one that supplies water to Saratoga residents. The plant is undergoing a five-year reconstruction that includes a revamp of the treatment process. That means it’ll be switching from powdered activated carbon to remove compounds such as geosmin to ozone which, Hong said, is far more effective at removing odors.
Influenced by the food and beverage industry, the practice of using human palates to discern taste and odor anomalies in water was started by the Metropolitan Water District in Los Angeles in 1997 and spread to water districts throughout the state a year later. Flavor analysis was implemented as a standard in the water industry by the American Water Works Association, according to Hong. Today, the panel is an important part of the district’s water quality monitoring efforts, she added.
One “purpose is kind of to put us in the customer’s shoes and see the public’s perception of water,” she said. “If there’s some odd smell or taste, people will think, ‘Oh, it doesn’t smell right; I’m not gonna drink the water.’ So that’s why we take water odor issues very seriously.”
There are 11 members on the flavor profile analysis panel. One employee from the San Jose Water Company, the district’s biggest retailer, is invited to participate in each tasting. To become a member, candidates must be an employee of the district and pass a smell identification test. Applicants get four booklets with 10 scratch-and-sniff tests in each and are asked to identify the scent. To pass, they can’t get more than three scent identifications wrong. Those who fail can retake the test six months later.
Once they pass the scratch-and-sniff test, they are eligible for six months of training, during which they are required to attend and participate in every panel meeting. Their ratings don’t count, however, until they’re a regular member of the panel.
As valuable as a refined palate is, there is one downside. Castro said she has developed a sensitivity to odors—even the pleasant kind.
“It does make me a little more sensitive to perfumes and colognes,” she said. “I find it almost overpowering now.”
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