Q: Can you find out if Washington and Oregon grapes are sprayed with the pesticide cryolite (aluminum sodium fluoride)? A: Cryolite is an...

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Q: Can you find out if Washington and Oregon grapes are sprayed with the pesticide cryolite (aluminum sodium fluoride)?

A: Cryolite is an insecticide widely used in California vineyards. A leading manufacturer of the product, marketed under the name Kryocide, has posted an advisory online. It states that studies done in the 1990s by cryolite manufacturers, E&J Gallo Winery, the Wine Institute and California State University, Fresno, collected data to determine use patterns of cryolite which could keep fluoride-residue levels at or below 3 ppm, the European standard (European regulations on fluoride residues are stricter than those in the United States).

One conclusion was that “It is important to recognize that there will be some low level of fluoride in wines, even in wines made from grapes that were not treated with cryolite. Research at California State University, Fresno, has shown that fluoride levels in wine produced from grapes not treated with cryolite can range from 0.1 to 1.6 ppm, depending upon location and variety.” At the time of the studies, appropriate guidelines were established to keep residual fluoride in wine at acceptable levels (below 3 ppm). Recently, some wineries which export to Europe have experienced situations in which this limit was exceeded. Because of this, some wineries have again instituted a prohibition on the use of cryolite. This seems to have brought the question back into the spotlight.

Happily, it does not seem to be an issue here. Vicky Scharlau, the executive director of the Washington Association of Wine Grape Growers, confirms that “It is not used in Washington. It is an insecticide that works against pests we don’t have.”

Paul Gregutt answers questions weekly in the Wine section. He can be reached by e-mail at wine@seattletimes.com.