Issue link: http://read.dmtmag.com/i/123973
SOIL REMI COHEN & CELLAR Yet they aren't completely accurate, especially at low Brix, due to alcohol's interference in the results. A more accurate measurement can be made with a density meter – such as a DMA from Anton-Paar – which has integrated functions that can be selected to calculate the desired density-dependent properties such as Brix and alcohol percentage, and compensate for temperature. Portable versions, which can run a few thousand dollars, can be quite handy to track fermentation progress in the winery. As Brix levels approach zero, it's best to perform glucose and fructose readings on a spectrophotometer to determine residual sugar level. This test can be outsourced to an off-site lab, or can be performed inhouse if the winery chooses to purchase a spectrophotometer. TESTING PH, TA, VA For determination of pH, only a pH meter is needed, which can be purchased for a few hundred dollars. A stir plate with stir bars, and perhaps a hot plate, can also be useful. Standards and buffering solutions are the reagents needed. In order to analyze for total acidity, a titrator apparatus needs to be set up. This requires a burette with a stand and clamps, the pH meter and stir plate (although phenolphthalein can be used for endpoint identification), a few beakers and volumetric pipettes, and normalized sodium hydroxide and hydrochloric acid reagents. In keeping with low-tech solutions, a simple lab can afford to have a cash still for measuring volatile acidity. One can be assembled for less than $1,000. Other low-tech and relatively inexpensive items to have handy include a microscope for detecting the presence and species of microorganisms. better accuracy than Ripper, but it also it takes about 10 minutes for free SO 2 and 30 minutes for total SO2 per sample. SO HOW'S THE S02? The analysis of SO2 is one of the most frequently conducted winery lab analyses, and there are affordable methods for wineries of any size. The Ripper method is an iodine titration that can be performed with about $200 of titration equipment. However, each sample requires 10-15 minutes, accuracy can deviate by as much as 10%, and the color change is not obvious in red wines, making this analysis less than desirable. Iodine is also a controlled substance, which makes it more difficult to use the Ripper method. The most common and also affordable method is the aeration/ oxidation method, which can be set up for approximately $500; it has Automatic titration systems can cost anywhere from a few hundred dollars to several thousand. Photo: Hanna Instruments Automatic titration systems for SO 2 analysis are also available, including ones from Hanna Instruments and Mettler Toledo, costing from a few hundred dollars to several thousand. These instruments help the user avoid overshooting the titration endpoint. Some titrators come pre-programmed with numerous analytical procedures, including procedures for pH, free SO 2, total SO2 and total acidity, among others. California-based Vinmetrica has a partly automized SO 2 analyzer (SC-100 and the SC-300, which Wine Analysis Don't just hear it on the grapevine • 170 Wine tests per hour • Improved efficiency • Reduced costs • 1 Calibration per harvest • Reduced cost per test • Easy to Use Wine & beverage testing kits available: Acetic Acid Ammonia Copper Ethanol Glucose/Fructose Iron Lactic Acid Malic Acid Potassium Total Antioxidant Status Total S02 FOOD DIAGNOSTICS Randox Food Diagnostics, 515 Industrial Boulevard, Kearneysville, West Virginia, 25430 T +1 304 728 2890 F +1 304 728 1890 E enquiries@randoxfooddiagnostics.com I www.randoxfooddiagnostics.com w w w. v w m media.com M a y - J u n e 2 0 13 | V I N E YA R D & W I N E RY M A N A G E M E N T 37