Showing posts from February, 2012

2012 McLaren Vale Vintage - Part 1

Grape harvesting in the McLaren Vale wine region is progressing very well. The harvest is running earlier than average, following on the trend first seen by an early grapevine bud burst and flowering last spring.
At the end of February, most white grapes varieties and approximately half of the Shiraz crop has been picked, with some early Grenache also being taken into wineries.
Summer has been warm, but vineyards have been spared the trials of extended heat waves. The weather has been ideal for ripening except for some sites being exposed to high strength gully winds. While wind damage has left these vineyards looking a little rough round the edges, fruit quality has been unaffected.
Widespread rain in the last 24 hours is expected to hold up harvest until conditions have dried out. Hopefully this will not cause widespread berry splitting, or promote late season bunch botrytis.
Winemakers reports so far have been glowing. Bryn Richards from Chapel Hill says, "We harvested …

Salinity in grapevines - Time to apply post harvest leaching irrigation

All of these vineyards pictured are showing foliar signs of sodium chloride toxicity, more simply called salt uptake.
In these situations it is essential that salt is leached from the soil to reduce excessive build-up over seasons. Typical leaching fractions may be in the range of 10 to 20%, and are best applied prior to bud-break if soil testing shows salinity levels were not reduced sufficiently by winter rainfall.
In addition consider the use of Humic acid. Humic acid can reduce the effects of soil salinity in simple terms because it binds with sodium and prevents it being taken up by the vine.
Care of grapevines with salinity - GWRDC Factsheet.

Gully winds and range clouds - local weather conditons and ripening in McLaren Vale

20/12/2012 – At this time of the year grapegrowers are constantly looking at the weather. The pictures on this page show a common localised weather pattern in the McLaren Vale Wine Region.
Locals call it a gully breeze.
In this picture a strong breeze is blowing from the ‘range’ (the Southern Mt Lofty Ranges) towards the camera, while a ‘range cloud’ sits on top of the hills. These 'range cloud' conditions slow grape and horticultural ripening rates, in February, March and April, on the Fluerieu and at Kuitpo. The corresponding gully breeze is famous for its strength and duration in McLaren Vale.
The technical name for this cloud formation and accompanying wind is 'Orographic.' Orographic clouds form when humid air blows over the top of the hill range. The air first rises to go over the hill range then, on the downwind side of the range, the air sinks back into the valley and warms. During warming the water droplets (i.e., clouds) evaporate into invisible water vapor.

Chardonnay - 'The Brown Grape'

Studies of Chardonnay wine quality showed that wine made from sunburned grapes is darker with bitter characteristics. Preventing sunburn is one of the key factors to achieving wine quality in Chardonnay.
Sun exposure in all white wine grapes may result in increased phenolic concentration (Macaulay and Morris, 1993), and berry shrivel and browning (Tarara et al. 2000).
Interestingly the application of commercial ‘sunscreen’ products (calcium carbonate and kaolin clay) can prevent this, but has not been widely used in the marketplace by grape growers.
Further Reading.
Macaulay, L. E., and Morris, J. R. (1993) Influence of Cluster Exposure and Winemaking Processes on Monoterpenes and Wine Olfactory Evaluation of Golden Muscat. Am. J. Enol. Vitic. 44:2:198-204
Tarara, J. M., Ferguson J. C., and Spayd, S. E. (2000) A Chamber-Free Method of Heating and Cooling Grape Clusters in the Vineyard. Am. J. Enol. Vitic. 51:2:182-188

Irrigation in the lead up to harvest.

Mid to late season irrigation is critical to the quality and yield of your vineyard.
This stage utilizes approximately 36% of the annual water requirement. Deficit irrigation can reduce yield and even affect ripening and fruit quality. Severe deficits will cause leaf defoliation.
Did you know?
Different grapevine cultivars have evolved various strategies to deal with water deficit.
Isohydric (pessimist) – conserves available resources by early stomatal closure and subsequent reduced gas exchange.
Anisohydric (optimist) – maintains a higher rate of gas exchange for immediate gain at the expense of stored soil water.
Rootstock genotypes may vary in sensitivity to soil moisture levels and subsequent hormonal production.
More more information - GWRDC. Relationships between yield and water in winegrapes. Yasmin Chalmers, DPI-Mildura

Rain before harvest - UPDATE 6/2/2012

Heavy rain has fallen in and around the McLaren Vale Wine Region. Aldinga had 15.6 mm. Seaview had 27.4 mm. Look out for botrytis ignition points like this Light Brown Apple Moth damage shown in Shiraz (above).

Early report from McLaren Vale a grapegrower; “We had 17.5mm of rain overnight and up to 11am. Heavy rain but no hail. Strong westerly winds seem to be drying the canopy. Can’t see any obvious berry splitting.”

Any berry splitting will become obvious in the next 48 hours. Early monitoring reports are showing very minor berry splitting, if any.

Ripening EL35 - UPDATE 4/2/2012

Weather update
The only negative weather effects seen are from wind damage, caused by strong gully winds, and sunburn that is widespread in white varieties where they were exposed to the west.

Some thunderstorm based rain is expected on Sunday. The forecast is for ‘a few showers.’

At this point there is no significant bunch botrytis detected. Some growers are taking early action for botrytis.

In McLaren Vale Chardonnay is harvest ripe. Shiraz picking will begin in 16-21 days in McLaren Vale. Lower cropped vineyards can ripen very quickly, so make sure to sample them regularly.

In the Adelaide Hills Cabernet Sauvignon has 20% veraison. Vineyards in Mt Compass are at a similar ripeness level. These vineyards will need careful monitoring over the next month if we get significant rain.

Salt Damage - ID Photos

Summer dry weather conditions mean that some vineyards are showing damage from salt (sodium and chloride). As soil moisture reduces vines pull water harder from the soil (plants create a negative pressure from the leaves to the roots - pulling harder means a higher negative pressure).
As the vines pull harder they take up more salt with the water. Eventually the concentration in the leaves becomes toxic and the leaves 'burn.' Sodium and Chloride levels in the developing fruit also increase which can have a detrimental effect on wine quality. Vineyards in the Langhorne Creek region are suffering from excessive uptake of Sodium and Chloride into their fruit.
Salinity in the vineyard can be measured by:
• irrigation water - amount of dissolved salts, electrical conductivity (ECe) and sodium adsorption ratio; • the soil - salinity and exchangeable sodium percentage; and • the vine - sodium and chloride levels in the fruit.
Look for leaves that are small, curled downwards and bro…