Sunday, 7 September 2014
During the last few weeks the grapes have started their ripening process, which in viticulture is called veraison. The Pinot Noir and Pinot Meunier grapes change colour from from green to red and the Seyval and Chardonnay turn more translucent.
Grape berries have two distinct growth phases. The initial phase is when the cells divide and expand and the grapes begin to swell and fill out the bunch. After veraison the acidity decreases due to degradation of malic acid, making tartaric acid the predominant acid. At the same time sugars (glucose and fractose) are accumulated and the volume of water entering the grapes decreases resulting in an increase in sugar concentration. The level of sugar accumulation in the berries is dependant on leaf photosynthesis which is why we are hoping for some more sun! This week we will also be trailing a product made from yeast derivatives which is designed to improve the phenolic maturity of the berries.
As the fruit ripens it becomes more attractive to the birds so we've put up our KiteHawks which will hopefully keep them at bay.