I’m out in the vineyard looking and tasting around the blocks and bunches, probing through the vines looking for the precursors of ripeness that allows the forward planning of harvest and the attention to detail that will allow for the quality and quantity that we require for the coming vintage.
The preceding couple of weeks here in Margaret River have thrown up some challenges with inclement weather, including rainfall and humidity, the result of some botrytis and additional risk management that includes removal of disease affected fruit and spraying to protect have kept us busy. Fortunately that the weather returned to warm and windy following the rainfall and this has helped dry out canopies and the fruit and allowed natural limitation of the spread of disease.
We are now well into harvest of white varieties and most of us are working nights to take advantage of the much cooler temperatures that have followed quite hot days. We know that these fluctuations between daytime heat and night time cool are influential in providing evenness of ripening within bunches and then a relief period for the vine (technically, the cool night time temperatures allows the vine to recover and the cool period reduces the energy requirements that would otherwise be used in respiration/evapotranspiration, which in turn reduces the consumption of acids as a energy source….) The result of this diurnal temperature phenomena caused by the proximity to the Indian and southern Oceans and the influence of the sea breeze is intense fruit flavor with increased natural acidity, attributes that occur naturally in our amazing Margaret River Region.
The fruit quality prospect this year looks very good. The more understanding about quality factors as a result of plant responses to environmental conditions the more we understand that “mild stress” on the vines, at certain times through the growing season, can vastly improve the potential for outstanding wine quality production.
As a primary indication of fruit quality in red varieties, we know that vines that cease growing new foliage approximately 20 days before veraison will start a process of change that encourages greater colour, flavour and aroma production in the berry. This is a normal plant response to “mild stress” conditions that gives the greatest opportunity to encourage seed distribution, a natural evolutionary plant response for species protection. Fruit that has ripe seeds and no green fruit flavours (green flavours are a natural animal and insect deterrent) adds to the potential for seed distribution. Of course we circumvent seed distribution by excluding birds and other pests and we take the fruit for our own consumption. Somewhere in all this “mild stress” of vines results in smaller berry size, itself being a precursor to improved flavour and colour intensity of fruit. Most of the colour is found in the skins and flavour compounds are found just under the skin; small berries have more skin and less pulp in a ratio that increases colour intensity and flavour. With all these factors coming forward we can already see that the potential for quality fruit production out of Margaret River this year is real and we live in expectation of an abundant yield of technically ripe fruit.
As we travel around Margaret River we can see bird nets to protect grapes from the hungry silvereye birds that can ravage berries and cause havoc to ripening fruit. We can also see the native Marri trees (E. Calophylla) have started to flower and this will provide some relief from bird damage as we get further into vintage. The nectar from Marri blossom is a much preferred food source for the silvereye and while there is blossom the pressure on vineyard people to deploy nets is reduced. An interesting fact is that silvereyes that only have grapes as a food find it difficult to survive as they can’t replace the energy used in seeking out and eating grapes and will loose condition. Grapes are way down the list as a food preference for silvereyes and they are desperately hungry when feeding on grapes. Simply, the biologic “engineering” of the silvereye only allows the beak to penetrate the skin of the grape and then by extracting the beak and then licking the silvereye consumes a small amount of sweet liquid, the sum of which generally doesn’t equal the amount of energy expended in flying and other activities. The major issue with silvereyes is that the damage done by piercing the berry results in secondary infection by moulds and bacteria that spoils the grapes for winemaking. The best protection is placing netting over the vines and this has become an annual event in early February, the result is less angst and growers and viticulturists can sleep easier once the nets are on.
The delivery of perfect cool white grapes to the winery results in happy winemakers, accountants and owners, not only is the quality of wine enhanced but also the energy required in cooling juices to allow cold settling prior to fermentation is curtailed and the cost saving for electricity consumption is achieved. Of course, the whole planet benefits from this reduction in energy consumption and it’s another great reason to be growing grapes in our fantastic Margaret River Region.
Contributed by Bruce Pearce c/o the Margaret River Wine Industry Association.
Margaret River Discovery Tours
Sean Blocksidge is the owner operator of the Margaret River Discovery Company, an avid photographer, blogger and South West WA ambassador. In 2010 he won Western Australian Guide of the Year and his tours have been rated the #1 thing to do in Australia on the Tripadvisor website for the past two years.