Should be crop high or low for pinot noir sparkling base wines?

Good quality sparkling wine grapes command a premium price in Australia, in particular those from cooler climates, such as in Tasmania. It is generally accepted that Pinot Noir can be cropped higher for sparkling wine production than for table wine production, but the effect of this increased crop load on the base wine composition is relatively unknown. The current trial was carried out over three seasons in a commercial vineyard in Northern Tasmania on own rooted, 9 year old, clone 114 Pinot Noir vines. Varying crop load was achieved by altering winter pruning levels to leave 10, 40 or 60 nodes per vine by laying down 1, 4 or 6 arms per vine, with 10 nodes per arm. Fruit was harvested and small scale winemaking was carried out, using a standard protocol (12 kg ferments). The significant increase in yield decreased total soluble solids (TSS) at the highest crop load. Other fruit composition parameters indicated that seasonal variability had a stronger effect than pruning level. Although TSS values were similar between seasons, varying levels of total anthocyanins and phenolics were recorded with the 2011 the lowest season, which was quite a wet season and 2012 highest which was a mild and drier season. Low and high crop load treatments separated from each other on Principal Component Analysis (PCA) scores plots, with varying results for the medium crop load treatment according to vintage. The PCA loadings plots indicate that hydroxycinnamates are impacted upon by the variation of Pinot Noir crop load.