3.2. Winemaking

Grape bunches (~60 and ~100 bunches per treatment for Shiraz and Cabernet Sauvignon, respectively) were destemmed by hand and berries divided (by mass) into three fermentation replicates (per treatment, of ~2.5 kg each). Berries were then crushed by hand, with 50 mg/L additions of sulphur dioxide (added as an 8% solution of potassium metabisulphite) and pH adjustment (to 3.5 with a 10% solution of tartaric acid) made to must prior to inoculation with 300 mg/L Maurivin PDM (AB Biotek, Sydney, NSW, Australia) and addition of 200 mg/L of diammonium phosphate. Musts were fermented on skins at 18–20 °C, with the cap plunged twice daily. Wines were pressed when residual sugar was <1 g/L and cold stabilized at 0 °C for 8 weeks.

Following cold stabilization, samples (150 mL, per replicate, per treatment) were taken for chemical analysis, before wine replicates were assessed by four sensory experts from the University of Adelaide (all female, aged between 25 and 56 years) to establish there were no off-flavors or obvious differences between replicates. Replicate wines were then blended for sensory analysis (i.e., to give one blended wine per treatment).