Three men and a woman sitting at a table poured liquid from a jar into Styrofoam cups, swirled it gently, sniffed the aroma and recorded their observations in notebooks. Then, each took a sip, wrote additional comments and announced their findings aloud.
"Kind of swampy," said one. "Chalky and swampy," offered another. "Rubbery," said a third.
No, this wasn't a bad wine from a bad year, or the losing cola in a Pepsi challenge. It was water, vintage 1985, drawn from Southern California reservoirs and filtration plants owned by the Metropolitan Water District.
The tasters were giving their opinion so that the swampy, chalky, rubbery qualities could be corrected before delivery of the water to consumers.
About three times a week, bottles of water from various points in the MWD system are subjected to the sensitive noses and palates of a panel of trained water tasters assembled in La Verne in the San Gabriel Valley. And even though the MWD recently dedicated a new $6-million water quality laboratory that boasts $1 million worth of high-tech instrumentation, the district's most sophisticated detection devices lie in humans, not machines.
"The human nose is more sensitive than any analytical equipment we have," said Michael J. McGuire, MWD water quality manager.
McGuire said machines excel at quantifying impurities, but "when you use machines, you have to know what you're looking for." By describing what they sniff and taste, trained water tasters help point machines in the right direction.
If, for example, the tasting panel detects a musty odor in the water--an indication that algae may be present--that finding leads to action to correct the problem.
The MWD organized the tasting panel in 1981 with the help of a consulting firm experienced in flavor-profile analysis of food and beverages. MWD lab employees adept at detecting and describing odors and tastes were named to the panel and trained to identify constituents in certain products.
Stuart Krasner, senior chemist and member of the panel, said one training exercise involved tasting different parts of an apple, including stems, peels and seeds, and then figuring out whether an applesauce contained whole or peeled apples. With practice, panelists learned to notice subtle differences in products.
Krasner, whose hobbies include gourmet cooking, said he has become very good at picking out spices and other ingredients in exotic dishes in restaurants. "I don't have to worry about the chef withholding the recipe," he said.
Turns His Brain Off
Overdeveloped senses can sometimes be a nuisance, however. Krasner said that if he tastes root beer carefully, he picks up an unappetizing odor that can be smelled in ointments. He stopped drinking root beer for a while, he said, but now when he drinks it, "I just turn my brain off."
Panelist Warren Schimpff, who is also a chemist, said that the ideal water is "something that is refreshing. It has very little taste and does not leave a bad taste in the mouth afterward."
"If it's devoid of minerals, it can be too flat," he added.
McGuire said that taste in water is as varied as the people who drink it. Visitors from Europe, for example, he said, often object to the "chlorine taste" in local water. Yet, he said, residents may want to taste chlorine because it gives them assurance that the water has been purified.
The MWD imports water from Northern California and the Colorado River for delivery to water agencies that serve 13 million people in Southern California. Each source of water has its own characteristics. Colorado River water is comparatively heavy in minerals while the Northern California water has more organic chemicals, but McGuire said the characteristics change as the water flows into reservoirs and through the MWD system.
The panel regularly samples water taken from various points in the system and checks out consumer complaints.
Summoned on Weekends
Krasner said the panel is sometimes summoned on weekends or asked to work overtime. When the MWD began adding chloramines (a combination of chlorine and ammonia) to the water in November, Krasner said, some consumers complained of a fishy or swampy taste to the water. The panel's taste analysis identified microorganisms, which were removed by adding chlorine to a reservoir outflow before the water received the chloramine treatment.
Members serve on the taste panel in addition to their other duties as scientists and technicians at the lab. The panel has nine members, and at least four or five attend each tasting session, because some members may be more sensitive to certain kinds of tastes and odors than others.
McGuire said the tasting panel is just one small part of an increasingly sophisticated effort to detect water impurities. The new water quality lab at the F. E. Weymouth Filtration Plant in La Verne is three times as big as the old lab at the same location. The number of lab employees has grown from nine in 1973 to 43 today. Last year, the lab conducted 93,000 tests to look for 200 substances.
1 Part per Trillion
McGuire said it is only in recent years that labs have been able to detect substances in minute amounts, as little as one part per trillion. One part per trillion is equivalent to a few drops of ink in enough water to fill the Rose Bowl, he said.
Unfortunately, McGuire said, "Our ability to analyze what is in the water has far outstripped our ability to understand what it means." For example, he said, the health effects of drinking water tainted by tiny amounts of chemical compounds in the one-part-per-billion or -trillion range is unclear and it may be economically impractical to remove all impurities at the levels at which they can now be detected.
But, McGuire said, MWD water delivered to consumers meets all health standards and is as safe to drink as bottled water or water that has gone through a home filtration system.
McGuire said he hopes that the new water quality lab and the fact that the MWD is spending $4.1 million a year on its testing program will help "allay any public concerns about the quality of our water."
'Our ability to analyze what is in the water has far outstripped our ability to understand what it means.'
--Michael J. McGuire
MWD water quality manager