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Monthly Report - March 2008

A Stressful Occupation…


March is a month that seems to be a bit of a sleeping monster, on the outside all is lovely amongst the vines with fruit ripening in the autumn sun but lurking in the background is this fear of the uncontrollable.  During the month you become a victim of circumstance, all the effort put into the vintage is now placed in jeopardy by the weather, any ex-cyclone coming down the coast or an early break in the season with unseasonably cold weather is not unreasonable occurrence in our corner of the globe.  As I type this report out, the remnants of Cyclone Pancho is now heading east and leaving about 11mm of rain behind, which is exceptionally lucky as we could have easily received 75mm and the vineyard would have looked like a wet poodle.  We still have two varieties to come off and we have to hope that the weather can hold together for a further 8-9 days such that all the fruit comes off with maximum flavour retention.


Why rain and cool weather is such an issue with the regions vineyards is that excessive amounts of either will dilute and disease the crop.  Rain falling on to ground which has been irrigated and flat lying will soak easily into the root zone and this will be put into the fruit quite rapidly, reducing sugar levels, upsetting the acid balance and scalping flavours – this is a generalisation of course (some varieties need some finishing rains) but for the Bordeaux varieties it is not the best case.  Cool weather can also be as disruptive as it starts to shut the plant down and the increase in sugar levels cease but the acidity continues to fall without the ripening of tannins and other grape components that are critical in fine wine.  Again some varieties can handle cooler weather and complete more slowly (Cabernet varietals are good examples), but for grapes such as Shiraz and Grenache this is a real problem.


We have managed to complete one major pick with the Merlot being harvested on the 29 March.  The long growing season and the dry month of March has ensured that the grapes have arrived with Sharna (our winemaker) having full flavours and excellent tannin development – it will be an interesting wine to watch develop and it may show a bit of vintage variation that makes our site so complex and interesting.


A graphic reason…


For followers of this report it will come as no surprise to you that I will wander off down the path of graphs and explanations at some point every year.  One of my interests is why the vintage pans out the way it does, every year the flavours and acid balances come in at a specific point (we pick within 2-3 days of the flavours being at their peak), and yet the past four years the last 3 months of vintage have been very similar in temperature and rainfall.  Thus it is the months of late spring and early summer that make all the difference to our picking schedules, and by using the month of October prior to vintage there is a marked correlation shown.  Below is a graph that shows this correlation such that with a few more vintages data we should almost be able to predict picking dates by the end of October, 5 months before harvest!

200803_Heat Load Graph.jpg

The tasting room

This graph is not fully tested and the heat load values have been worked out by averages, so it really is just an indication and if I get more time to spend on this topic I will try to get more accurate values for our site and maybe provide a prediction at the end of October 2008 for the picking dates of the 2009 vintage.  However by glancing across the graph it looks like the Cabernet Franc this year should be in full flavour and ready to be picked on about the 9th April – here’s hoping.



Like a ticking bomb...


As alluded to at the start of this report, March is an extremely variable month and has the opportunity to be both very wet and quite cool.  Fortunately this was not the case in 2008 leading into an excellent finish to the growing season for the varieties left to be picked.


The numbers for the month and last year’s figures are provided below:

March 2008:     

Avg Maximum Temp          25.0°C

Daily Max recorded            29.8°C


Avg Minimum Temp           13.0°C               

Daily Min recorded               7.7°C


Rainfall:                               37.0mm

The 2008 maximum temperature average was lower than last years, but this is only due to 3 record breaking hot days in early March 2007 and if these values were reduced to the average then the heat load in both years would have been very similar.  Rainfall is very similar in both years with 3-4 rainy days in each making up the small total.

March 2007:      

Avg Maximum Temp          25.6°C

Daily Max recorded            38.5°C

Avg Minimum Temp           11.2°C

Daily Min recorded               3.2°C


Rainfall:                              25.4mm


The comparison with Sonoma Valley continues with the data from the month of September (northern hemisphere’s equivalent to March) 2007 is presented below:

September 2007:      

Avg Maximum Temp          27.2°C

Daily Max recorded            36.7°C

Avg Minimum Temp            7.4°C

Daily Min recorded              1.1°C


Rainfall:                              0.0mm


The temperature range continues to intrigue me as there are such hot day time temperatures continually chilled by the night time air.  It really is a different climate to us here in Margaret River and must provide completely unique challenges to the viticulturists and wine makers of the region.  Rainfall is again nil and this gives a total over the past three months of nil as well – that is dry!


Finish of Vintage…


The last of the nets and picks should be out of the way by mid-April giving us a chance to have a look at the ferments and see what we have in the form of quality for the 2008 vintage.  A lot of work goes into this one chance of making a cracking wine each year and the relief at the end of vintage is a very pleasant feeling and guarantees a few meals with friends in the industry and a few bottles opened as well.


All the best everyone.





Mark Gifford

Blue Poles Vineyard

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