Moss Wood 2009 Semillon

Vintage Notes

We can look back at the 2008/09 growing season and feel very comfortable with the results.Mother Nature was generally kind to us, providing near perfect conditions for vine growth and grape ripening. A particular highlight were the warm but moderate temperatures, where we experienced more hours in the effective range for grapevines than in any season for the last 10 years. It allowed the fruit to ripen slowly but consistently and we avoided any of the quality threats associated with either extreme heat or cool.

The weather station data provides some interesting insights. During the period from flowering to harvest, both the Semillon enjoyed almost exactly 1000 hours in the temperature range of 18 to 28 Celsius. In a cool season like 2006 they will receive between 600 and 700 hours and on average, they receive around 900, so this year they spent many hours in the right range to ripen grapes. Extreme temperatures were also avoided, with a total of only 20 hours above 30C during the same period. This compares with the average of around 47 hours, so the vines suffered no extreme heat stress. During the last few days of February we had a rain event that delivered 24mm and was just enough to worry us.

The vines pick up the freshly available soil moisture, causing the grapes to swell, sometimes diluting the sugar and in the worst case, splitting, which permits the development of fungal diseases like Botrytis. Semillon has a soft skin and is prone to the latter so we monitored both Moss Wood and Ribbon Vale blocks very closely. Fortunately both coped well with virtually no damage. We feel the quality of the 2003 vintage was diminished by a similar event and have been wary ever since. In 2009 we didn’t see the same problem and suspect this year’s lower yield was the key. In the end, the rain washed off the dust and generally freshened the vines up, so it was all good. In terms of the actual length of the season, as usual, things varied between varieties. The Old Block Semillon at Moss Wood ripened a little faster, taking 96 days to go from flowering to harvest, compared with its average of 110. However, it was harvested on 10th March, only three days earlier than the average harvest date of 13th March. It may come as no surprise to learn it flowered 12 days later than average. The Semillon needed 114 days to get from flowering to harvest compared to the average of 115 days and its harvest date of 20th March was virtually identical to its average of 19th March. On the down side, yields in 2009 were disappointing. Moss Wood Semillon cropped at 8.24 tonnes per hectare, down 25% from its long term average of 11.01. If we look at the days taken to go from flowering to harvest, it’s possible to see a bright side to these low yields. It made the grapes ready to pick earlier than average, despite the mild summer, the smaller crop load ensured we got the harvest in before the arrival of autumn rains.

There appear to be at least two reasons for the poor yields. The biggest impact appears to have been fewer bunches on the vines which were well down on previous years. The vines tried to compensate with slightly above average bunch weights but this did not fully compensate. Of more interest was how the moist, cool conditions promoted a greater and later than usual hatching of the “Looper” caterpillars. They are rarely seen in the vineyard but this year we had infestations in vines near native trees. It was fortunate they weren’t widespread because they had a particular taste for the young flowers and happily chewed the ends off them. It’s difficult to estimate what damage they caused but about 5% of vines were affected and on those, about a quarter of the bunches had been chewed, but not all the berries.

Production Notes

The production technique was as follows. The fruit was destemmed, crushed, passed through the must chiller for cooling to 8C then pumped into the press.

The juice was gradually squeezed out with a gentle cycle and racked to stainless steel tanks. The final pressings were kept separate for additional fining before being blended back later in the process. The grapes were brought to the winery and destemmed, This is important in reducing the phenolics in the finished wine without stripping too much flavour. After this the juice was settled for 48 hours at 8C and then racked to another stainless steel vessel for fermentation. This was carried out by a pure yeast culture (V1116) at 16C. Fermentation lasted for 19 days, after which the new wine was racked off its gross lees (fermentation sediment) ready for bottling preparations.

Fining trials were carried out and eventually the Semillon was treated with bentonite for protein stability. It was then cold stabilised, sterile filtered and bottled on Monday 29th June, 2009.

Cellaring Notes

This is a full flavoured white wine, with generous fruit flavours providing attractive early drinking but it is also a very good cellaring prospect.

For those with the patience for cellaring, the wine will develop slowly over the next 10 years, by which time it will show the beginning of a complex, toasty bottle bouquet.