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February 2015 practical winery & vineyard 71 w i n e m a k i n g a n d at e n .w i k ip e d i a.o r g/w i k i/ Carboxymethyl_cellulose. How is CMC integrated into cellar practices? CMC should be dosed at 100 ppm of pure carboxymethyl cellulose: check the CMC concentration for the product you are using and calculate the dose appro- priately. The CMC should be diluted in two times the dose volume of wine and then thoroughly blended with the total volume of wine to be treated. The CMC addition should be at least 48 hours before final filtration and bottling to avoid any adverse filtration effects. CMC should be the last treatment to the wine before bottling. Any additions or treatments that could affect the col- loidal stability of the wine should be avoided. Additions that are compatible with or after CMC addition include: sul- fur dioxide, gum arabic, carbon dioxide and ascorbate. All other additions in- cluding acid, sugar/concentrate or wine blending should be avoided. Use of CMC as a non-subtractive tar- trate stabilization agent creates an en- tirely new paradigm in wine processing. However the addition of CMC is not a simple plug and play substitute for tra- ditional cold stabilization; the evaluation criteria for CMC use and the timing of operations are different. While traditional cold stabilization is a cellar process performed sometime be- tween the end of fermentation and bot- tling, CMC KHT stabilization should be thought of as the last treatment of the wine before bottling. CMC use criteria include wine protein/heat stability and involve caution for lysozyme-treated wines that should be bench-trialed for CMC compatibility. Excess proteins in unstable wine can interact with the nega- tively charged CMC and may result in a haze formation in the treated wine. The initial tartrate instability of the wine should be below 30% by DIT or the UC Davis conductivity testing. Wines should be clean and well-clarified before CMC addition, a clogging index filterabil- ity measurement below 30 and an NTU reading below 4.0 for white wines and below 6.0 for rosé wines is recommended with pre-filtration highly recommended. Temperature of the wine should be greater than ~15º C (59º F) before CMC addition and throughout final filtration and bottling to ensure normal wine vis- cosity and an easy filtration. Pressure at bottling should remain below 0.8 bar, which would indicate that there is no blocking of the filter that could retain some of the CMC, potentially impacting the final effective concentration of CMC in the finished wine. Calcium is another use-criteria con- sideration. Because CMC protects only against KHT instability, calcium levels should be below 80 ppm to minimize the risk of CaHT crystal formation. Wine de- acidification with calcium carbonate or specific vineyard soil and rootstock ef- fects can result in high calcium levels in must and wine. It is best to check the incoming must for calcium content as treatments exist for lowering initial calcium content very early in must/juice treatment or during fermentation, creating compatibility with CMC for later stabilization application. Case studies and results of CMC addition CMC is a robust treatment method to achieve KHT stabilization. Applications of CMC for KHT stabili- zation in major North American white wine varieties such as Chardonnay, Sauvignon Blanc, Pinot Gris, Riesling, Gewurtztraminer, Chenin Blanc and numerous white wine blends and di- verse varieties have all proven effective. Since the introduction of CMC into the U.S. market in 2012, more than 2 million