Out in the vineyard last evening looking at colour change of red varieties and it is noticeably cooler at night and some moisture in the air creating a moderating influence on the mild to warm daytime temperatures. This difference in diurnal temperature is one of the many attributes that has Margaret River wine region producing consistently high quality grapes that promote flavor, colour and aroma while preserving the natural acidity. The warm days, breezes from the Southern and Indian oceans and cooling nights during the maturation period result in slow and even ripening of grapes and a conservation of the acids that would be otherwise consumed as an energy source with evapotranspiration in hot weather with warm nights.
Quality and quantity…These are key words that could be used to describe the future 2017 vintage in Margaret River. After a cold and wet start to spring and early summer, the vines then responded well to a warming trend through December and January, providing mid-sized canopies with very little amounts of lateral shoot growth. These canopies have required far less maintenance to present fruit yield to canopy ratios that enable airflow and fruit distribution to enable evenness of ripening.
The veraison period is characterized by the change of hard green berries into soft sweet berries that in red varieties see change in colour and in white varieties sees opacity and a change in colour to golden colours. In recent years, the weather and growing conditions have prompted a progressively earlier veraison and consequent harvest dates and this phenomenon could be explained by warming weather trends. However, there are many other contributing factors to explain earlier vintage dates and there is a strong relationship between increasing canopy surface area and lower yields (due to poor weather at flowering and plant nutrition imbalances) that would increase metabolic rate of the vines and could influence earlier vintages. The interesting fact is that vintage dates have been moving forward a few days every year since 2010. The 2016 vintage was the earliest we have ever experienced. This vintage (2017) will be three to four weeks later than 2016 and is more in line with the 2009 vintage…. Will 2017 be recognised as a late vintage or is it just more in line with what we knew back in 2009?
Veraison is now progressing in near perfect weather and most of the varieties have entered the veraison period with ripening fruit showing flavour intensity at this early stage of development.
One of the many challenges that viticulturists are encouraged to perform is predicting the tonnage of fruit and providing this information to the winemaker. Predicting tonnage can be done relatively easily and a few “old hands” can just look into the vines and provide a visual estimate with some accuracy; well, most of the time (I like this method and will admit to not always getting it right!). There is some science that can be applied and growers will go to great lengths counting bunches per vine, counting berries per bunch, weighing berries and then applying a correction factor to enable a more scientific prediction on what fruit will come from a hectare of vines. The science used for forecasting a crop yield relies on the fact that berries have a lag phase of development just prior to veraison. Simply, the berry stops growing and remains relatively constant in weight. The lag phase in berry development can last between 7 to 40 days. The length of the lag phase determines whether a variety will be early or late maturing. Although this sounds complex, we know that if we sample and weigh bunches just prior to veraison and then apply a standard for accumulation of sugar (add 20%) and then allow a reduction for bunch stalks (subtract 5%) and harvester losses (subtract 5%) we can come up with a number that may represent the final yield delivered to the winery at harvest. OK, OK! enough on yield forecasting, I hear you say!! What is important is that in 2017 we reckon on having a normal to slightly higher yield at vintage and that’s what we are planning for. It goes without saying (but I will anyway), that the weather and other influencing factors up until harvest will change yields.
To a great extent, most of the grapes harvested in the early phase of vintage this year will be picked by hand. In this set of circumstances, we prefer to harvest Chardonnay with whole bunches and go straight to press to reduce extraction of phenolic hardness usually associated with crushing and then pressing (simply, it just means that by just pressing the free run juice out of berries that the finished wine has tantalizing mouth feel and makes the best quality wine….). Some of the hand harvesting is done for sparkling wine base and this requires delicate handling and cooling before processing to reduce colour extraction. We are certainly gaining a reputation for our sparkling wines from Margaret River and those that are lovers and “in the know” find the bubbles attractive.
Hand harvesting can be a challenge, especially in hot weather and with helpers that come from all corners of the globe we have to be considerate and allow time for them to adjust to the climate and the job at hand. We are very fortunate that we have the environment that attracts travellers to Margaret River and creates the situation for employment with backpackers and travellers earning some money before moving on and roving further into the state. The warm weather can test the mettle of a few new chums to Margaret River but the attraction of money, “all the grapes that you can eat” and the prospect of adding extra time for international working holiday visitors drives them on. After a hard day picking grapes, I’m sure a beer, a kind word and surf helps ease the pain and makes the stay in Margaret River pleasurable and memorable.
Many tourists come to Margaret River purely for the natural environment, the National Parks and Coastal attractions. We are incredibly blessed with natural biodiversity throughout the Margaret River wine region and at present we have the most spectacular Marri tree flowering in our forests. Observing the flowering we can see many buds yet to burst and therefore the promise of lots of blossom still to come. Eucalyptus Calophylla is the botanical name of what we know commonly as Marri or Red Gum and the significance of this flowering gum at harvest is flowers full of nectar are a preferred food source for the marauding silvereye birds. With the prolific blossom, the silvereyes are satiated on nectar and leave the grapes alone. In years like this when the blossom is so prolific there is little motivation to apply bird netting, a saving in labour and machine hours and making life a little easier out in the vineyard.
Out in the Vineyard
Contributed by Bruce Pearse, Viticulturist
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.