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October 2015 P R A C T I C A L W I N E R Y & V I N E YA R D 61 W I N E M A K I N G In this study it was difficult to separate the type of light from the temperature effects, but because higher ambient tem- peratures at disgorging are associated with gushing, our results suggest that sparkling wine bottles should be disgorged (neck freezing, crown cap, lees removal and dos- age addition) at an ambient temperature of 12° C under LED lighting. The effect of UV light on sparkling wine flavor and gushing is described else- where. 3,6 The wine in this study was bottled in green glass, not the more UV-sensitive clear glass. All bottles in our study were handled with great care to avoid shaking or disturbing the lees sediment. Estimated monetary loss One of the most significant aspects of gushing is the loss of revenue derived from the forfeiture of wine even if the bottles of wine are returned to a reserve tank (Table 2). Therefore, although our trial was on a small scale, we considered the monetary loss based on a $25 bottle of sparkling wine on a small run of 1,000 bottles (costs can be adjusted for larger quantity), see Table 2. If a winery or contract disgorging com- pany disgorges wine at an ambient tem- perature of 16° C, the winery will incur a substantially greater loss of income than disgorging at 12° C. Compositional differences of gushed and non-gushed bottles Although the three bottles of wine ana- lyzed prior to our trial were not tartrate- stable, we wanted to further investigate why some of the bottles gushed under the light/temperature conditions when others did not. Additional analyses revealed compositional differences in the bottles that gushed compared to those that did not gush. This observation suggests that bottle variation of the wine may be partly responsible (Table 3). The differences in bottle pressure were small and likely due to loss of force from gushing after disgorgement (pre-dosage addition stage when the crown cap was removed). The reduction in protein con- centration in all bottle samples after neck 40 30 20 10 0 10 LED 10 UV 12 LED 12 UV 14 LED 14 UV 16 LED 16 UV Bottle temperature (°C) and % of gushing bottles % of gushing bo les Bo le temp (°C) Figure 2. The percent of bottles that gushed after neck freezing and crown cap removal at each ambient temperature/light treatment and the mean wine temperature of each treatment. Insulated Bins MonsterCombo ® Bins Winetainer™ Bulk Barrel™ Rack-Master™ 2 & 4 Barrel Wine Racks Patent 646,040 Patent 628,355 S Solutions in Wine Making www.bonarplastics.com • sales@bonarplastics.com • 800-768-6246