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WineEast dependent on its pH, because really only a small portion of the free SO2 does most of the heavy lifting. In reality, free SO2 in wine exists in three forms: molecular SO2 , bisulfite and sulfite. Of these three species of SO2, molecular SO2 is the most potent antimicrobial agent, and its existence is favored by a lower pH. Therefore, the lower a wine's pH, the less free SO2 will be required. It is commonly accepted that a level of 0.8 ppm molecular SO2 offers ample protection from oxidation and most yeast and bac- teria. Many winemakers attempt to maintain a minimum of 0.8 ppm molecular SO2 throughout the aging period for white wines. Because they are usually dry, red wines have undergone a com- plete malic acid fermentation and possess the anti-oxidative proper- ties of their tannins. Therefore they require slightly less—more along the lines of 0.6 ppm molecular SO2 . Also, red wines usually have a higher pH, and maintaining a 0.8 ppm molecular SO2 The Hanna autotitrator 901 is set up for conducting SO2 and other titratable analyses. Focus on free SO2 Analyses will provide you with free SO2 in parts per million (ppm), which is the same as milligrams per liter (mg/L). With the same apparatus you may also determine bound SO2 is the more important number, since this is the form of SO2 . For now, free SO2 that is still available to act as an antioxidant and antimicrobial agent. The degree to which a given level of SO2 will protect a wine is highly , total acidity would give excessively high total sulfur levels, which can lead to off flavors and excessive color depletion due to sulfite bleaching. In any case, total sulfur levels should be kept below 200 ppm unless the impact of such a level is tested in the lab beforehand. Making adjustments To adjust a wine to a given molecular SO2 wine's pH and free SO2 SO2 Given Molecular SO2 amount of free SO2 molecular SO2 . level, first determine the , then consult the table "Amount of Free Level" on page 67. This will indicate the necessary to yield a given 0.8 ppm or 0.6 ppm You make the best wines... as ask for or the be esst eq pmenequuipment Tanks Variable capacity, closed top, combined tanks built to your requirements Equipment • Presses • Crusher destemmer • Pumps and more. plus a variety of tanks in stock. Get a quote online now at www.raynoxinc.com 1148 St-Michel street, St-Cesaire, QC, Canada, J0L 1T0 Phone (450) 469-4822 Toll Free 1 866 469-4181 Wines & Vines JUne 2011 67