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124 W i n e s & V i n e s n O V e M B e r 2 0 1 4 increasing maturity of the fruit, also reduce the levels of MP. One factor that has proved to be a good predictor of MP levels is temperature. Higher levels of MPs occurred in warmer years, as warm climates stimulate vigor and therefore higher MPs. In cooler climates, warmer temperatures (especially early in the growing season) have been shown to result in higher MP levels. Once the grapes arrive at the winery, what can be done to reduce or remove those methyoxypyrazines? Because the MPs are found in the grape skins, good destemming practices will help to minimize the green flavors in white wines and, in some cases, settling will also reduce the green aromas and flavors. However, during red wine fer- mentation, these compounds are extracted from the skins within the first two or three days and will remain a problem. Most winemaking interventions are either ineffective in terms of actually pulling out the MPs or they are not selective. yeast se- lection can help, as yeast strains known to produce strong, estery or fruity types of aro- mas may have the potential to mask some of those green flavors, but it is unlikely that the yeasts will actually remove the MPs. Oak exposure and micro-oxygenation don't remove the MPs, but both treatments can mask their effects. Use of activated char- coal can remove the compounds, but it is not selective and may be deleterious, espe- cially for premium red wines. Thermo-vini- fication, some packaging systems (such as Tetra Pak), and closures (such as synthetic corks) can either bind or pull out the MPs, WineEast Winemaking miwinebarrel.com Stainless Steel & Oak Wine Barrels... Midwest, East Coast, Great Lakes, Canada... miwinebarrel 734.398.2028 We now also provide... Custom Stainless Steel Tanks! Novel ways to reduce methoxypyrazines O ther strategies to reduce green flavors include using proteins to bind the me- thoxypyrazines, counter-fining with something else such as bentonite to bind the compounds and then filtering out the bound proteins. Flash extraction to remove MPs has been tried, but no data is yet available. While the technique may work, the equip- ment is expensive and beyond the reach of most small wineries. A different way of fining has been tried in which a non-polar absorbent is added to the juice or wine in the form of chopped up pieces of food-grade silicon tubing. Over a period of several days, there was a 90% rate of removal of the MPs—although this pro- cedure was more complicated for red wine must, as the MPs had to migrate from the skins before they could be bound to the silicon. However, currently this practice is not approved by the TTB for use in wine. L.J.M. Multicolored Asian lady beetles produce iso- propyl methoxypyrazines that give off-flavors. 360 E. State Parkway • Schaumburg, IL • 60173-5335 USA (847) 755-0360 • Toll-Free FAX: (800) 800-0320 International FAX: (847) 885-0996 • sales@kuriyama.com www.kuriyama.com The Kuriyama Value ™ Wine and Beverage Hoses POLYWIRE ® PLUS Suction & Discharge WSTF ™ Series Suction & Discharge 350LL Series Washdown CLEARBRAID ® Discharge FT ™ Series Suction 408LL Series Suction & Discharge Kuriyama of America, Inc. ™ 2013 Sc h a u m b ur g , Illi n o i s Anniversary 45th K U R I Y A M A O F A M ER I C A , I N C . 1968