Growing high quality Shiraz in the Barossa Chris Rogers St Hallett Wines
The Barossa first vineyards planted around 1842 Barossa zone ~169,000 hectares 1 13,655 hectares total vineyard, 7140 hectares of Shiraz (52%) 2 Barossa zone comprised of the Barossa Valley & Eden Valley regions Elevation of vineyards ranges from ~120m to ~550m 1 Growing degree days ranges from ~1370 to ~2080 1 Annual rainfall ranges from ~315mm to ~780mm 1 Patchwork of soils Highly diverse region! 1 Robinson S. and Sandercock N. (2014). An analysis of climate, soil and topographic information to aid the understanding of Barossa terroir. Prepared for the Barossa Grape and Wine Association by PIRSA Spatial Information Services 2 Phylloxera & Grape Industry Board SA, July 2014. SA Winegrape Crush Survey, Barossa Valley and Eden Valley Regional Summary reports 2013
Wine Quality / Wine Style Recognising quality relies on knowledge High involvement wine drinkers drive the discussion on quality as journalists, judges & buyers (Lockshin, 2002) their interest lies in the details their views influence consumer perception of quality Style is not strictly correlated with quality (Wine Spectator, 2014) High quality might also be defined as best in class or best expression within a given context
The Barossa journey Over 160 years of grape growing and winemaking experience... certain areas or sub regions recognised for certain styles of Shiraz a mixture of traditional & new viticultural practices have evolved Customers & consumers seeking more detail & connection with wines they like Grape growers, Winemakers & Wine Marketers seeking knowledge that can add value & sustainability clear and consistent messages for customers & consumers deeper understanding of the Barossa s attributes & diversity A collective will has emerged among the Barossa wine fraternity to compile a body of knowledge on the tapestry of the Barossa... the Barossa Grounds
The Barossa Grounds Project An ongoing journey of exploration, definition and communication Started in 2008 under the umbrella of the Barossa Grape & Wine Association detailed sensory assessment of benchmark wines extensive consultation with grape growers, viticulturists, winemakers, marketers, judges, journalists, soil scientists, climatologists, geologists, botanists, customers, consumers, historians Looking for common themes and differences Increase the scientific understanding of regional characteristics Aiming to add value to the regions wines Create communication tools... the power of maps Broad areas have been identified... Sub regions, Grounds or Parishes Can also add value to grape growing and winemaking
Barossa climate, soils & topographic analysis (2012 2014) GIS mapping and analysis of geology, temperature, rainfall, soils, elevation, slope, aspect in conjunction with vineyard area Undertaken by Spatial Information Services team of the Department of Primary Industries & Regions, and integrated knowledge from viticulturists & soil scientists to define data classes Soil water holding capacity an important indicator of variation across the region due to the Barossa s dry climate & limited irrigation resources Opportunity to assist decision making on irrigation resources, land use, climate risk & biodiversity strategies Immediate opportunities to create powerful & uniform communication resources to engage consumers and build brand value More site specific weather & phenological data being collected since 2013
The value of this knowledge Opportunity to target specific areas and sites to specific wine styles & quality levels Potential to also factor in yield capacity & management practices for optimal yield quality alignment St Hallett has been taking this approach for many years wines from over 100 Shiraz blocks are kept separate in the winery for as long as possible this has been immensely valuable to; developing a deeper understanding of Barossa diversity Helping to align areas sites quality style economics providing insights to the impacts of seasonal conditions tailoring winemaking practices to specific parcels/styles providing feedback to growers wine innovation opportunities (e.g. single vineyard wines) understanding vineyard management practices
Vineyard management practices for Barossa Shiraz Common ground Vine balance hard to measure but widely accepted as important to quality typically assessed visually relies on experience & outcomes sought fruit pruning weight ratios less subjective, but rarely used in practice Qualitative indicators of balanced vines often cited, for example; cessation of shoot growth before veraison moderate shoot & internode length moderate leaf size & low or nil lateral growth moderate small berry size but not a pre requisite to wine quality early & rapid lignification of shoots rapid progression through veraison consistent ripening rate
Pruning one of the most important practices to managing yield, canopy & wine quality in Barossa Shiraz most Barossa vineyards are pruned quite hard by wider industry standards to control yield in line with water availability & quality expectations aiming for consistent node number per metre & sustainable structure avoid spur congestion & bunch crowding > disease risk & quality issues? Shoot thinning maybe merited when targeting ultra premium Shiraz products can address shoot congestion issues in unbalanced vineyards some of the cost returned via lower winter pruning costs questionable benefits in the Barossa if it results in high bunch exposure Green thinning involves the removal of laggard bunches at late veraison may improve flavour uniformity across bunches low cost if done at the right time & percentages are low maybe merited when bunch distribution is variable and when targeting ultra premium Shiraz products
Yield No magic numbers here! Optimal yield quality balance is subject to; site/vine capacity inherent & managed target end use & economics seasonal conditions & resources available to support yield (eg water) Cropping levels at the upper end (of balance) increase risk to achieving consistent wine quality outcomes, but cropping at the lower end can increase risk of over ripe fruit and poor financial outcomes The quest for the sweet spot should also be about minimizing yield variability from season to season Past experience can be a useful guide to the sweet spot for a given vineyard if all else is equal
Vineyard uniformity Impacts of vineyard variability are well studied (Bramley et al, 2005) Precision viticulture presents opportunities to enhance quality & yield; currently low use of sophisticated technologies but simple methods often employed in Barossa Shiraz (e.g. zoning of irrigation & mulch) Selective harvesting can enhance quality outcomes but requires good fermentation capacity, forward planning and collaboration. Regularly used with success at St Hallett for ultra premium blocks Absence of diseases & pests a standard pre requisite to wine quality generally easy to achieve in the Barossa
Harvest timing & maturity is very important to wine style, wine quality, and yield outcomes in Shiraz St Hallett undertook trials in 2006, 2009 & 2012 to better understand these relationships in two specific vineyards commercial sized trials 10 tonne ferments & identical winemaking machine picked alternate rows to reduce variation (eg every 3 rd row x 3 in 2009) wines assessed by internal winemaker panel Primary aim of each trial; 2006 to examine the impacts of very high maturity on wine style 2009 to examine the potential to make a lower alcohol wine style 2012 to examine the yield quality balance in a specific vineyard
TABLE 1: St Hallett Wines harvest timing trials in Barossa Valley Shiraz Vineyard TSS (Be') 2006 VINTAGE Seppeltsfield vineyard Pick # 1 7 Mar 6.00 15.5 3.70 6.4 9.0 7.06 18.0 12.7% Pick # 2 13 Mar 5.24 16.3 3.90 5.4 15.0 6.16 18.5 6 2009 VINTAGE Rosedale vineyard Pick # 1 6 Feb 8.60 11.4 3.58 6.1 22.0 6.86 15.0 Pick # 2 Pick # 3 Pick date 16 Feb 26 Feb Days lapsed Tonnes 10 10 2012 VINTAGE Rosedale vineyard Yield Load analysis change Yield Wine assessment between (t/ha) picks ph TA Deg C (%) Score Comments 7.84 12.4 3.72 5.2 19.5 6.26 8.8% 16.0 6.96 13.7 3.80 4.9 24.0 5.55 11.2% 16.5 Pick # 1 14 Feb 10.30 14.7 3.78 5.4 14.0 6.06 16.57 4.7% Pick # 2 21 Feb 9.82 15.5 3.88 4.5 21.0 5.78 16.14 7 blackberry, firm ta nnins black olive, drying ta nnins cherry, wintergreen, light weight raspberry, light weight, firm tannins black fruit, mod weight, firm tannins red fruit, licquorice, mineral tannins blackberry, grainy ta nnins Weather summary 21.7 o C avg daily temp, no rain or heatwave 21.4 o C avg daily temp, hot before, no rain 24.1 o C avg daily temp, no rain, warm nights
Shiraz has unique berry vascular characteristics which make it more prone to berry weight loss than some other varieties (Tyerman et al, 2004), and the onset of weight loss in field grown Shiraz occurs at 90 days after flowering (McCarthy, 1999) The research of McCarthy (1997) and Rogiers (2004) showed berry weight reductions in the range of 10 30% The St Hallett trials showed weight losses of between 1% and 2% average per day over the harvest periods assessed Weight loss with increasing maturity, and the balance between maturity & wine quality, can vary significantly from year to year There can be trade off s between maturity & wine quality/wine style, especially at high maturities in Shiraz Berry shrivel is an important factor to consider in growing and making Shiraz wines more monitoring required
Ripening rates slow ripening = higher wine quality a misused concept sugar ripening ahead of flavour ripening is seen as unfavourable, but.. ripening rates needs to be looked at in the context of timing in the season and relative to similar vineyards St Hallett often observes the best quality Shiraz wines come from vineyards that ripen fastest and first within a given area Slow ripening appears most often associated with negative factors such as over cropping, too much/too little moisture, virus & leaf loss
Vineyard management practices Specific ground Attune management to the site, and to the target use Key factors to manage; Vine water status Soil Canopy management and row orientation Nutrition
Vine water status & irrigation management in Barossa Shiraz Irrigation is a very powerful management tool in Barossa viticulture Shallower soil sites make vigour & yield management easier, but require excellent irrigation infrastructure & resource availability to avoid excessive moisture stress and potential yield/quality loss General agreement around avoiding moisture stress from budburst to flowering to not limit canopy & yield Some planned use of RDI between flowering and veraison success depends on the season, and in dry years its hard not to have RDI! Opinions vary about irrigation management between veraison & harvest.. Prefer to avoid moisture stress just before and through veraison prefer to see unimpeded ripening and no leaf loss after veraison small frequent irrigations, and very frequent during heatwaves Too much moisture stress may reduce the expression of area/site?
Soil management many soil types in the Barossa which require different approaches eg sands versus black cracking clays Aim for optimal rootzone health in all cases to provide; resilient vineyards that can cope better with extreme heat events sufficient canopy without excessive vigour or canopy density consistent availability of moisture & nutrients through the season with less reliance on fertiliser inputs the reduced use of cultivation & greater use of organic matter inputs has improved yield and quality outcomes on many Barossa soil types Deeper alluviums require very little or no inputs, and may require the use of permanent swards to control vigour under vine mulch (compost or straw) beneficial on many soils
Canopy management in Barossa Shiraz largely about avoiding excessive bunch exposure in the Barossa Valley, although some sites in the cooler Eden Valley require opposite practices to avoid too much shade A trellis design that works well across many parts of the Barossa is a single fruiting wire with a static foliage wire 30cms above Reduces canopy roll which can cause excessive bunch exposure Easy to mechanise & no additional labour inputs East West row orientation is preferred over North South to avoid excessive heat on west side of canopy & bunches from afternoon sun
Searching for the sweet spot the quest for optimal yield and quality
Nutrition management in Barossa Shiraz Problematic nutritional deficiencies are generally low in Barossa Shiraz typically low yields reduce nutritional needs sometimes issues with low P, high ph soils and Zn & Mn Nitrogen requires close attention and a holistic approach to inputs N management is a balancing act Shiraz can over respond to N inputs due to inherent vigour, especially on deeper alluviums of the Barossa Valley Too little or too infrequent N can also be very problematic on low capacity sites; lack of canopy > slow ripening and/or excess bunch exposure reduced heat & drought tolerance low must YAN > stuck fermentation > lower wine quality Petiole analysis not ideal for N monitoring vigour, leaf colour & must YAN are probably better guides
ACKNOWLEDGEMENTS Nicki Robins, Barossa Grape & Wine Association Toby Barlow, St Hallett Wines Anthony Scholz, Scholz Estate Vineyards