Shiraz Colour zone g Chardonnay - USQ...
Transcript of Shiraz Colour zone g Chardonnay - USQ...
Overhanging foliage appeared to
lessen sunburn in all treatments;
fruit from control and netted vines
had the greatest leaf cover and the
lowest degree of sunburn. On the
Granite Belt site ambient light
measurements at véraison showed
leaf-plucked treatments had highest
exposure, data for the vertical plane
showing low light penetration in
most treatments with healthy
canopy, except the sprawl which
had little overhead cover. Over the
season the overhanging foliage was
progressively lost. Measurement of
bunch zone UV radiation in the
Shiraz indicated highest UV
exposure in the high plucked
treatments as well as slight
increases in sunscreen treatments;
while protecting the berries,
overspray on leaves may reflect
more UV radiation onto the fruit.
Queensland wine industry development has relied upon adoption
of viticultural practices from established winegrowing regions.
Such procedures are not necessarily best practice under
Queensland conditions. The wine grape growing regions of
Queensland are climatically distinct from other Australian
regions with relatively wet growing seasons, at times with severe
peak heat loads. Queensland also hosts the most northerly and
some of the highest altitude vineyards in Australia, with higher
ultra violet radiation exposure than any other Australian grape
growing region. Furthermore, fruit exposure may be exacerbated
by regional management practices used to minimise risk of
fungal infection. The Queensland wine industry has identified
fruit exposure management as a critical issue to be addressed.
An extension project was undertaken to demonstrate effects on
fruit exposure of alternative canopy management practices for
Chardonnay and Shiraz in vineyards in Queensland‟s Granite
Belt, South Burnett and Scenic Rim. Growers inspected the sites
in their regions prior to harvest, and fruit from the Granite Belt
site was harvested, chemically analysed and processed into wine
for sensory assessment. The wines were evaluated by judges at
the 2010 RASQ Wine Show and sensory profiles determined.
Findings were discussed with the Queensland wine industry and
wines made available for sensory assessment by participants in
the Queensland Viticulture Seminar in June 2010.
Fruit exposure was modified by fruit zone leaf removal from the
most easterly (low - L) or both sides of the canopy (high - H); at
pea size (P) or at véraison (V); a 50% shoot removal (ST);
throwover bird net (Net); application of commercial „sunscreen‟
products (calcium carbonate or kaolin clay); a non manipulated
VSP „control‟ (C); and „sprawl‟ for Shiraz. The Granite Belt
vineyard used for the demonstration was, unfortunately, subject
to hail and frost events in late 2009, resulting in some damage to
vines. This combined with late season water stress and disease
pressures to impact on the results of this trial.
All treatments fell within recommendations for leaf area / fruit
weight. Fruit analyses showed similar harvest yields and
profiles of TSS, pH, TA. Marginal differences were seen in
Chardonnay phenolic profiles and Shiraz anthocyanins, tannins
and phenolics, and while slight differences were seen, the
wines had similar sensory profiles.
METHODS
Differences were noted in exposure and sunburn of the Chardonnay grapes prior to harvest, although only marginal differences were seen in
the measures of fruit and wine quality of either variety. We are wary of making inferences from this study over a difficult season where site and
seasonal factors overwhelmed differences due to imposed management practices. Inconsistent additional fruit exposure occurred via
defoliation relating to early season frost and hailstorms and late season water stress followed by fungal disease pressure. We plan to follow up
with demonstration trials in vineyard sites with lower risk of unfavourable events.
Influence of Bunch Exposure in a Commercial Queensland
Vineyard on Chardonnay and Shiraz Fruit and Wine Quality
U. J. Kennedy1, T. Hassall2, M. Deegenaars1, D. J. Rhymer3 and R. P. Learmonth1
1CSBi, University of Southern Queensland, 2Queensland Primary Industries &
Fisheries, 3Ballandean Estate Wines, Queensland, Australia.
INTRODUCTION RESULTS AND DISCUSSION
CONCLUSIONS
This work utilised the facilities of the Queensland College of Wine Tourism, and was supported by the Queensland wine industry and the
GWRDC RITA grant RT08/03-1 “Addressing fruit exposure and sunburn in Queensland wine grape vineyards”. We would also like to thank
Sirromet, Clovely and Ironbark Ridge for provision of vineyard demonstration sites, the RASQ Wine Show judging panel, and Kim Larsen
(USQ) and USQ Wine Technology students for assistance with picking and processing grapes and juice and monitoring ferments.
ACKNOWLEDGEMENTS
At pre-harvest vineyard walks, it was noted that the worst
sunburn was seen in fruit with little canopy or leaf cover (leaf
removal or shoot thinned). Little difference in severity of sunburn
was seen between pea size and véraison leaf removal. In the
South Burnett and Granite Belt sites, the severity of sunburn was
equal or greater on fruit situated on the more easterly side of the
canopy, anecdotal evidence suggesting this may be due to
afternoon cloud cover typical in the region. Tasting fruit
indicated better acid and flavour balance on unexposed fruit,
with more exposed and sunburnt fruit showing overripe and
„cooked‟ fruit flavours and lack of acidity.
TreatmentContr
olLV LP
HV
HP S
TNet
CaC
O3
Kao
lin c
lay
Spra
wl
% U
V l
igh
t in
bu
nch
zo
ne
0
5
10
15
20
25
30% UV irradiation Shiraz
TreatmentContr
olLV LP
HV
HP S
TNet
CaC
O3
Kao
lin c
lay
Spra
wl
% v
isib
le l
igh
tin
bu
nc
h z
on
e (
ve
rtic
al
pla
ne
)
0
1
2
3
4
5
6 Shiraz
Chardonnay
TreatmentContr
olLV LP
HV
HP S
TNet
CaC
O3
Kao
lin c
lay
Ab
so
rban
ce
0
1
2
3
4
5Total phenolics
Total hydroxycinnamates
Total flavonoids
Estimate of brown pigments
TreatmentContr
olLV LP
HV
HP S
TNet
CaC
O3
Kao
lin c
lay
Spra
wl
mg
/ g
or
a.u
. /
g0.0
0.5
1.0
1.5
6.0
7.0
8.0Tannins (mg / g)
Anthocyanins (mg / g)
Phenolics (a.u. / g)
0
1
2
3
4
5
6
7
Clarity
Hue
Intensity
Herbaceous aroma
Berry aroma
Dark fruit aroma
"Overripe" aroma
Palate lengthAcidity
Bitterness
Astringency
Alcohol heat
Herbaceous palate
Berry fruit palate
Dark fruit palate
Control
Heavy pluck pea size
Heavy pluck veraison
Light pluck pea size
Light pluck veraison
CaCO3
Kaolin clay
Shoot thinned
Net
Sprawl
Colour
Palate
Aroma
Shiraz
0.0
1.0
2.0
3.0
4.0
5.0
6.0
Clarity
Colour
Herbaceous aroma
Tropical aroma
Citrus aroma
"Overripe" aroma
Palate length
Acidity
Bitterness
Astringency
Alcohol heat
Herbaceous palate
Tropical palate
Citrus palate
Control
Heavy pluck pea size
Heavy pluck veraison
Light pluck pea size
Light pluck veraison
CaCO3
Kaolin clay
Shoot thin
Net
Aroma
Palate
Colour
Chardonnay