Briar Ridge Vineyard say they came very close to producing two vintages in 2014, but full ripening of the second crop wasn't realized (due to rain) till just after New Year's Day, so it just qualified as 2015!
Intense summer heat, such as successive days of more than 30°C scattered with some at nearer 40°C brings risks of berry damage, not just confused ripening. Shading the grapes may not be sufficient.
What do humans do if exposed to the same? So why not? Apply sunscreen to the canopies. Many vineyards are doing it, and have been for years. Several of Tulloch's growers have tried spraying sunscreen, and Lindemans have too.
The logic is simple. Canopies are often sparse in the Hunter Valley, due largely to the humid climate, and trained in thinner vertical overhangs (VSP) to offer some shade to the berries. Leaves take the brunt of the withering heat and sunshine but berries too can shrivel and develop unpleasant phenolic characters. Ripening can be too rapid and the necessary shorter hang-time can restrict the quality potential of the wines. Phenolic aromatic unpleasantness in whites is not the only problem, early loss of acidity can lead to 'porty' baked red wines, lacking structure. Whites can be picked early to maintain acidity and avoid skin damage and juice taken off skins quickly but the wines often display a simple, fruity, drink now style; Sémillon being the exception.
Sémillon is still rightly treasured in the Valley, though it is particularly prone to sunburn. Chardonnay is generally excellent and Verdelho is a remnant from Madeira production days. Today, many non traditional white varieties are popular in the Valley, there is Vermentino, Gewurztraminer, Riesling, Pinot Gris, Viognier and Fumé Blanc. Yes, Sauvignon Blanc in the semi-tropical Hunter Valley (though many producers are trucking in fruit from cooler regions to get the quality for these varieties). Many are competent, many need avoiding; consumers are looking for 'something cool and different', says Matt Slew at Tullochs.
So how to protect the canopy and maintain acidity whilst moderating, slowing, photosynthesis for reds? Especially those blocks and varieties that ripen later.
Spraying calcium or clay based products seems to do the trick. Calcium, a limestone/chalk fine powder, is mixed with a wetting agent, a sort of glue to adhere the mix to the canopy (Canola Oil works well), and is liberally sprayed in the vineyard after berry set but before Veraison. Various commercial products are established, like Screen Duo(R) and Surround(R). The mix covers the leaves and berries with a fine white-blue sunscreen, much like an Aussie cricketer's face walking out at the Gabba.
This could be a great excuse in wetter climates where outbreaks of powdery or Downey mildew can now be excused as factor 16 sunscreen.
It wears off slowly, and can be washed off - so immediate rainfall could prove it a costly waste of time - and as it is a nutrient the covering does not affect the final taste of the wine.
Results over some five years have seen slower ripening, longer hang-time and greater, cleaner complexity in wines.
Brokenwood senior winemaker Stuart Hordern says several of his growers are experimenting with sunscreen sprays, "there's a whole vineyard (not his) in Lovedale that glows pale blue as you drive past", he quips. Only for Sémillon, though and he is not sure it will become standard practice. "We didn't need it in 2015 or 2013 so it is yet unproved".
McWilliams Mount Pleasant haven't felt the need for sprays, either, they believe the age of some plots, especially those from the 1880's, makes them immune to everything except nuclear attack.
The water shortage in the Hunter Valley, though not as severe as that in the Western Cape, means that spraying is a serious decision. Tests have shown the need to be around 800 litres of water per hectare and maybe two applications. Most wineries in the Valley have a dam, or two, and these are still at healthy levels, but using as little water as possible is an accepted principle. 'Low Volume' spraying is the key, and restricted time spraying, at dusk or dawn, and at low water-to-mixture concentration; just enough to enable a fine mist over the canopy. The product cost for the 2014 Hunter season came in around R1 - R2,000 per hectare. Even then, the decision may be made for the winegrower by nature, severe drought may make sunscreen application difficult for those with little water, but for those with water access a dry, hot and sweltering summer might still make clean, balanced, elegant and complex wines possible. Mind, the sprays have to be applied before the heatwave or they are ineffective - so a crystal ball would be a good investment.
Winemakers may soon be picking up sunscreen along with packaged yeasts and fining powders.