Identification of the major drivers of 'phenolic' taste in ... - GWRDC

AWRI: Identification Of The Major Drivers Of ‘Phenolic’ Taste In White Wines
Hyperoxidation (HOX-LHP): 100 L of the FR, HP or 50:50 mix of FR and HP juices were
immediately sparged with 100% oxygen at 8-10 L/min until a dissolved oxygen value of
approximately 40 mg/L was reached, measured using a Nomasense PSt3 optrode.
Cold soak/maceration (MAC): destemmed and crushed must from 750 kg was held in either the
Willmes press (2010), or a 1,000L (2011) open fermenter sealed with shrink wrap film, with 100
mg/L SO2 as PMS solution added for 60 hours at around 5°C. It then followed a standard press cycle
with combination of pressings and free run.
Fermentation on skins (SKI): 2.5 kg of crushed grapes were added to 25 kg of FR juice.
Solids fermentation (SOL): FR juice was not cold settled with pectolytic enzyme prior to
fermentation.
Fermentation, Fining and Bottling
The juices were pH adjusted using tartaric acid or potassium carbonate, and (excepting the solids
ferment treatment) were cold settled with the aid of pectolytic enzymes for 24-48 hours. They were
then divided into 2 x 30 L fermentation vessels and inoculated with S. cereviseae strain EC1118.
Bentonite (Sodium) was added (1 g/l) to every vessel in order to achieve protein stability. The ferment
proceeded at 0.5 to 1.0 °Bé per day until dryness. Thereafter, 60 mg/L SO2 (as PMS) was added
before storing the wine at 0°C.
20 L vessels were completely filled with the finished wines under dry ice protection. Tartrate
stabilisation was carried out by seeding with 4 g/L KHT at 4°C once any necessary final pH/TA
adjustments were made. If required, further bentonite was added for protein stabilisation at the level
determined by the 80°C/2 hour test with the sample passing if