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April 2018 WINES&VINES 73 PRACTICAL WINERY & VINEYARD WINEMAKING that often accompanies such wine is also perceived to be less. With the exception of oak chips and some enological tannins, tradi- tional additives and fining agents have not proved effective at reducing greenness from MPs in either red or white wines. 19 Two materials not traditionally used in winemaking hold considerable promise for remediating wine with elevated MPs. Treat- ment of both red must and wine with silicone resulted in a large reduction in several MPs and, importantly, without significantly chang- ing desirable aromatic compounds. 4,8,26 Simi- lar results have been reported in red wine with elevated concentrations of IPMP, IBMP and SBMP when treated with a biodegradable polylactic acid-based polymer. 8 (See "Reduc- tion in Methoxypyrazine Content in Wine After Treatment with Silicone and Polylactic Acid Polymers" on page 72.) How these polymers can best be integrated into the winemaking process remains to be determined, but there are several promising avenues. For example, polylactic acid can be manufactured in a variety of forms with dif- ferent physical properties, allowing for flex- ibility in how it might be used. Potentially, it could be integrated into existing filtration systems, manufactured as solid tank inserts or added as pellets directly to the juice/wine and later removed when the target reduction in MP content has been attained. 8 A prototype fining system using a protein (mMUP Odorant Binding Protein) with very high specificity for MPs has recently been developed. 13 The protein, when introduced into grape juice, binds to MPs with the MP- protein complex then efficiently removed with bentonite fining. Optimizing the system for use on a commercial scale and in a wine matrix is under development at the Cool Climate Oenology and Viticulture Institute at Brock University. Finishing, closing and storing wine Depending on the extent of greenness, blending can be a useful tool, particularly if it is used in conjunction with other treat- ments to reduce the concentration of MPs to below their detection threshold. If a vintner is only using sensory analysis to arrive at the optimum blend, it is important that several palates guide the decision- making, given the wide range of sensitivities to MPs outlined above. Bottling both white and red wine in Tetra- pak cartons has been shown to reduce MP content by 26% to 45% after 18 months of storage compared to glass bottles. 1 However, the concurrent scalping of desirable flavor compounds from wines finished in multilayer aseptic cartons such as Tetrapak also needs to be considered, 27 as does the relatively rapid loss of free sulfur dioxide. 1 Some research has indicated that exposure to light after bottling can reduce IBMP by up to 57%, particularly with storage in clear bottles. 16 Other studies have found no consis- tent effect from light exposure, bottle hue (clear, green and amber) or storage tempera- ture on MP levels. 2 Some synthetic closures have shown marked capacity to reduce MP content in soaking trials, 22 and significant but smaller effects have been observed in bottled wines closed with synthetic closures compared with screwcaps and natural cork. 1 Simply aging bottled wine can reduce IBMP and IPMP by Fill your bottle selection with... Fill your bottle selection with... a a c w i n e . c o m a a c w i n e . c o m All American Containers Local Inventor y | S uperior S election | E xper t Advice Windsor, CA • San Leandro, CA • Kalama, WA Blending can be a useful tool, particularly if it is used in conjunction with other treat- ments to reduce the concen- tration of MPs to below their detection threshold. • GranuBent PORE-TEC premium bentonite • VinoStab CMC tartaric stabilization • VinPur Special gentle fining www.erbsloeh.com info@winer ystuff.com Quality made in Germany Make this year's wine a first class vintage with first class products