The purpose of this experiment was to determine the level of fluoride in red and white wines from grapes sprayed with Cryolite at specific rates and application times. A five-year study conducted by CSU Fresno has conclusively shown that applications of Cryolite increase fluoride levels in red and white wines. From 1990 to 1994, different rates and timing combinations were tried in an effort to clarify the role of Cryolite in wine fluoride. In 1994, confirmation of a 6-pound full bloom rate was the basis for an application and timing trial tested on seven different vineyards in the northern, central, and southern San Joaquin Valley. Zinfandel, Barbera, Chardonnay, French Colombard, Muscat Canelli, and Thompson Seedless varieties were studied (Table 1). At CSU Fresno, a replicated experiment was performed on Thompson Seedless, Zinfandel, and French Colombard. The treatment schedule is listed in Table 2. Treatments were applied at each site using grower-supplied equipment. At Simpson Vineyards, because of a change in cultural practices, vines were sprayed with a backpack sprayer. At CSU Fresno, applications were made with a single row over-the-vine boom sprayer. Application dates for each site are shown in Table 3. Insect populations were monitored frequently during the growing season. No plots received applications of other non-fluoride containing products, but all other normal cultural practices were performed. Soil and water samples were taken from each site at the start of the experiment, and water samples were taken just prior to each application, to analyze for fluoride. Samples were analyzed by the Ion Selective Electrode (ISE) method. At harvest, grapes from each treatment were crushed, some juice kept aside, and the remainder made into wine. Grape juice was analyzed for fluoride by ISE., The wines were bottled and analyzed for fluoride by ISE. The water and soil fluoride levels are listed in Table 4. Water fluoride levels ranged from 0.04 to 0.48 ppm. Soil levels ranged from 0.59 to 1.73 ppm. Soil and water do not greatly influence the fluoride levels found in wines made from grapes sprayed with Cryolite, because the levels of fluoride in wines were not consistently higher to correspond with these water and soil levels. Both untreated control (Tl) juice and wine samples had less than 1 ppm fluoride. Wine and juice samples that received 6 pounds at bloom or pre-bloom (T3 or T4) had between 0.27 and 1.94 ppm fluoride. Applications at shatter (T5) had the highest fluoride levels, leading to the conclusion that later applications cause increased fluoride levels. Results of juice fluoride samples are listed in Table 5 and wine fluoride samples are listed in Table 6.
/wp-content/uploads/2017/09/AFV-Header-Logo.png 0 0 AVF /wp-content/uploads/2017/09/AFV-Header-Logo.png AVF1994-11-22 17:34:372017-11-22 17:35:28The Effect of Application and Timing of Cryolite on Fluoride Levels in Red and White Wines