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48 WINES&VINES February 2016 BARRELS PRACTICAL WINERY & VINEYARD tific collaborations for red wines with California State University, Fresno's Aude Watrelot and James Kennedy (now of Constellation Brands) and for white wines with Regis Gougeon and Maria Nikolan- tonaki of the University of Dijon (Burgundy, France). Materials and methods The wood used in this study came from Vicard Group's stocks (French forests and neighboring countries) w i t h 3 0 m o n t h s o f n a t u r a l maturation. Wood classification according to ellagitannin content, as de- scribed above, was performed using NIRS with a detection tech- nique based on the use of an acousto-optic tunable filter. Each barrel was placed on a rotating plate with a toasting pot under a hole in the center of the plate. Agglomerated oak pellet material (made from waste at the stave mill) was augured into the toasting pot. For optimal combus- tion, air was blown into the pot using a fan. A computer controls the auger and fan. A barrel-shaped cone (inside the outer dome) cov- ered the fire, creating radiant heat, and a smokestack vacuumed smoke from the chamber when the unit was closed. When the outer dome was shut, all environmental fluctuations of temperature or hu- midity were eliminated. A toasting profile was entered into the computer prior to toast- ing. An infrared thermometer, aimed inside at the mid-point of the barrel, provided temperature readings as the barrel turned on the rotating plate. Readings were continually sent to the computer to adjust the temperature by speeding or slowing the auger and/or the fan to maintain the requested toasting profile or maintain a specific temperature. In our study, all barrels under- went a gradual toasting, and vari- ous initial temperatures were compared for: Merlot (G150) for estate A; Cabernet Sauvignon 160° C and 170° C (G160 and G170) for estate D, and 180° C (G180) for e state B; Chardonnay I vory (160°/170° C) for estate C. The gradual toast profile was designed to slowly increase the temperature NATURE AND ORIGIN OF WINES Origin Vintage Grape variety Toasting process Tannin potential (TP) Total polyphenol index (TPI) INFLUENCE OF TP Estate A Saint Emilion 2014 Merlot G150 LTP / MTP / HTP 84/83/86 Estate B Napa Valley 2013 Cabernet Sauvignon G180 LTP / HTP 70/78 Estate C Burgundy 2014 Chardonnay Ivory LTP / HTP nc INFLUENCE OF TOASTING LEVEL Estate D Sonoma County 2013 Cabernet Sauvignon G160/170 LTP 58/59 LTP=low tannin potential; MTP=medium tannin potential; HTP=high tannin potential; nc=not concerned