|Lower leaf yellowing.|
The growth stages recorded early this week have ranged from 100% verasion in Pinot Noir and Pinot Gris, to 40% coloured in Grenache. Where tested for maturity these varieties are testing above 10oBe.
Many vineyards are now showing lower leaf yellowing as pictured above.
Some of the early season white varieties, Sauvignon Blanc, Verdelho and Chardonnay are nearing ripeness. The run of hot weather this week is expected to push much of this fruit to be near harvest within 5-10 days. This is particularly true for vineyards used for sparkling base wines.
It is likely that this hot spell before harvest will cause some harsh phenolics if vines are temperature stressed. Also be careful harvesting in warm temperatures to avoid oxidisation. Many wineries advise the use of PMS (Potassium Metabisulphate) in picking bins.
At this time of year in the Adelaide Hills and Southern Fluerieu ripening begins to slow compared to the warmer climates of Barossa and McLaren Vale. Over the last few days dews have occurred and in general night-time temperatures are much cooler. These blocks still have 4 weeks to harvest ripeness for the early varieties.