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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 59 W I N E M A K I N G wines to gush. Therefore, our treatments were 10°, 12°, 14° and 16° C ambient tem- perature and up to 90 minutes under UV lighting or LED lighting. On March 13, 2015, at Tawse Winery in the Niagara region of Ontario, Canada, bottles of a 2013 sparkling Riesling pro- duced by méthode champenoise (12 months of yeast contact in bottle) from the Twenty Mile Bench sub-appellation were taken from various locations within a riddling cage, placed in a neck freezer and had their crown caps removed. There were 10 bottles per treatment for a total of 80 bottles. Before disgorgement, while still neck down (riddled), bottles were subjected to light exposure by placing them in card- board wine shippers with each side and top removed, leaving the corners and bot- tom of the shipper to support the bottles, to mimic the light exposure of a commer- cial riddling cage. Wine samples were analyzed in tripli- cate following filtration with a 0.45-micron syringe filter where appropriate. Triplicate analysis of TA (g/L), pH and SO 2 were carried out on three bottles prior to neck freezing and disgorging to account for bot- tle-to-bottle variation according to methods from P. Iland et al. (2004). 5 Bottle samples of the wine were ana- lyzed for ethanol content (% v/v) using a GC-Flame Ionization Detector. All bottles that gushed pre-dosage addition and three non-gushed (no dosage added) from the same temperature-treated and light-exposed treatments were analyzed for bottle pressure, protein (heat) stability, protein concentration, tartrate (cold) sta- bility, residual sugar concentration, malic acid concentration, phenolic concentration and yeast cell count. Interior bottle pressure was measured using an Aphrometer after disgorging and before dosage addition. Protein stability was analyzed according to a heat test, where a 10 mL sample was placed at 80° C in a water bath for 30 minutes. Samples were cooled for 45 minutes, inspected visually for precipitate formation, and the turbidity measured by nephelometry, expressed as nephelometric turbidity units (NTU). The difference in turbidity (ΔNTU) between the heated and non-heated wine samples was proportional to the protein instability, where a ΔNTU of less than 2.0 is considered heat/protein stable. 13 The total protein concentration was mea- sured using the Bradford assay and a spec- trophotometric absorbance reading at 595 nm and expressed in mg/L. 11 Tartrate/cold stability was measured by storing an unfiltered sample at -2° C for 72 hours, and stability or instability was assessed visually by formation of precipi- tates or cloudiness post-incubation. Residual sugar (g/L) and malic acid (g/L) were determined by enzymatic assay kits following the manufacturer's protocol using a UV-VIS spectrophotometer. Total phenolic content was analyzed by a spec- trophotometric absorbance reading at 280 nm. 2 Yeast cell count was carried out using a haemocytometer, and all statistical analy- sis was carried out using XLSTAT 2014. RESULTS AND DISCUSSION Chemical analyses of wine prior to disgorging Following chemical analyses of the bottle samples before neck freezing and lees removal, it was evident that the three bot- tle samples analyzed (to allow for bottle variation) were not tartrate-stable (Table 1). When the bottle sample was filtered, the crystals could be clearly seen on the filter pads, and when tested post-filtration were found to be stable. Bottle samples for analyses were taken before disgorgement from the top of a rid- dling cage and therefore were not repre- sentative of the entire 504 bottles in that FOR MORE INFORMATION, CONTACT ATP AT (707) 836-6840 OR ONLINE AT WWW.AMERICANTARTARIC.COM Introducing the Dynamos Introducing the Dynamos flter from TMCI Padovan. It's the world's frst patented high~solids, rotary, flter Introducing the Dynamos flter from TMCI Padovan. It's the world's frst patented high~solids, rotary, from Introducing the Dynamos flter from TMCI Padovan. It's the world's frst patented high~solids, rotary, TMCI Introducing the Dynamos flter from TMCI Padovan. It's the world's frst patented high~solids, rotary, Padovan. Introducing the Dynamos flter from TMCI Padovan. It's the world's frst patented high~solids, rotary, It's Introducing the Dynamos flter from TMCI Padovan. It's the world's frst patented high~solids, rotary, the Introducing the Dynamos flter from TMCI Padovan. 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