Chemical and sensory effects of cofermentation and post‐malolactic fermentation blending of Syrah with selected Rhône white cultivars.

Background and Aims: Whereas cofermentation is a traditional practice in some Old‐World regions, its outcomes are largely unknown in New‐World wine regions. Herein we report the chemical and sensory effects of cofermentation of Syrah with selected Rhône white cultivars. Methods and Results: A Control wine comprising 100% Syrah (SY), and five SY blends [consisting of addition by mass of 10% pressed solids of Viognier (VG), Marsanne (MR), Roussanne (RS), Picpoul (PC), and Grenache Blanc (GB)] were produced. In addition, juice from each white cultivar was fermented separately and blended with finished SY wine at a rate of 10% after malolactic fermentation (MLF). Cofermentation had no effect on wine composition, but blending post‐MLF increased ethanol concentration. Cofermentation resulted in lower concentration of most anthocyanin pigments, whereas blending post‐MLF had the opposite effect. Tannins were higher in SY‐VG, SY‐RS and SY‐MR blends, whereas polymeric pigments increased in SY‐RS post‐MLF and SY‐PC post‐MLF. This was attributed to enhanced copigmentation due to comparatively higher concentration of anthocyanins and flavonols in post‐MLF blended wines, which resulted in a hyperchromic shift at 520 nm. Addition of VG, either as a coferment or as a blend post‐MLF increased the aromatic complexity of the resulting wines. Conclusions: Of the white cultivars studied, VG appeared to provide more aromatics both as a coferment or post‐MLF blending option. Post‐MLF blending gave increased aromatics and colour, while offering greater flexibility and fewer logistical issues than cofermentation. Significance of the Study: The use of VG as the preferred coferment of SY, and the practice of post‐MLF blending of SY with a small amount of white wine, were validated through chemical and sensory analysis. [ABSTRACT FROM AUTHOR]