VINTAGE NOTES

A quick review of the weather we experienced during 2019-20 growing season suggests things were fairly comfortable.  Calendar year 2019 was a little bit on the dry side and we recorded a total rainfall of 779mm, 24% below average but still plenty for growing unirrigated vines.

To explain our thinking on this point, Keith likes to make the comparison with McLaren Vale in South Australia, where he grew up.  That region receives an annual rainfall of 658mm and back in the old days, when the vineyards there were unirrigated, the crop levels, on old-fashioned trellises were around 5 tonnes per hectare.  In one of our driest years, we’ve had 18% more rain than that and so we could make the observation that if our vineyards aren’t yielding well enough, lack of water may not be one of the causes.  It also goes some way to explaining why our long-term Cabernet Sauvignon yield is just over 7 tonnes per hectare.

The drier weather meant that flowering conditions were very good.  During this crucial period in November, the Cabernet varieties experienced only 5 wet days and we received a meagre 8 mm of rain in total.  With the dry conditions came moderate temperatures and we only had 4 days when the temperature dropped below the crucial 8°C.

Yet, despite these favourable conditions, Cabernet Sauvignon yields, at 4.5 tonnes per hectare, were down around 40%.  This begs the questions, where did we go wrong?

To find the answer, we have to go back to 12.15am on Thursday 24^th October, 2019.  In the pre-Covid world, Clare and Keith had just returned from Singapore, having met their new baby grand daughter, Matilda.  Arriving back home late in the evening on a rainy night and just settling into bed, there was a tremendous drumming on the roof that could only have been one thing – a hail storm.  We have a rough rule of thumb about hail – if it lasts for 5 seconds, damage will be minimal but for every additional 5 seconds the damage goes up by 5%.  As we lay there listening and counting, after 30 seconds it was becoming worrying and after 40 seconds, we pulled the covers over our heads and pretended we couldn’t hear it.  A walk through the vineyard confirmed the 5 second hail rule had definitely applied and there was significant damage to bunches and shoots.  All that remained was to see exactly what the losses were, although this never really becomes clear until the fruit is harvested.

To discuss this a bit further, there are a few key points about hail damage.  The vines are usually only at risk when they have soft green tissue and bunches, that is, during spring and summer.  During the autumn and winter, when they are protected by their bark, only a very extreme storm will cause any harm.  When we get growing season hail, there are essentially two parts to the process.  The first is the actual physical battering the plant receives when hit by the stones, causing bruising and wounding on the soft green tissue.  The second stage is when fungi then establish themselves in the resulting wounds and which exacerbates the yield loss.

We can’t do much about the first stage, unless we were to cover the entire vineyard in hail netting, an expensive and unrealistic option, given the probability of damage is relatively low.  However, we can apply fungicides to treat the infections resulting from the second stage and hopefully limit the resulting losses.  This means we move quickly after a hail event and get treatments on as fast as we can and in 2019, we had these applications on within 48 hours.

Once all this settled down, we went back to a normal, comfortable season and then just before we started vintage a new challenge raised its ugly head - Covid-19.  The world was starting to deal with its emergence and we watched on with worry as governments around the world began applying increasingly strict measures, leading eventually to lockdowns.  These coincided with the later stages of our harvest and in particular, the picking of our Cabernet Sauvignon.  There was a brief period where we were concerned our picking team and winery crew would be forbidden from attending work, although fortunately, that didn’t eventuate.  As things turned out, agriculture was deemed  essential work (something with which we’ve always strongly agreed) and so our people were able to travel freely.  For a day or so, it looked like we’d all have to stay at Moss Wood and simply not leave the property but fortunately it didn’t come to that.

After all this it’s nice to return to the most important thing, wine quality.

In the background, the vines were doing their thing, ripening the grapes in excellent weather conditions.  Temperatures were moderate, with virtually no extreme heat and our warmest day was 37 °C.  The Cabernet varieties made their way steadily to full ripeness, very slightly ahead of average, no surprise given the significant crop loss.  For the record, Cabernet Sauvignon took 116 days to go from flowering to harvest, compared with the average of 121.  Cabernet Franc took 111 days, a week less than average.

We now arrive at another of the season’s oddities, Petit Verdot.  This variety is VERY sensitive to flowering conditions and will abort its berries at the slightest hint of inclement weather.  Yet, in 2020, the year of the hailstorm, it managed to produce a yield of 5.81 tonnes per hectare, 12% above average.  The obvious conclusion is this block was less exposed to hail damage, which is how it appeared after the event.  However, under normal circumstances we would still have expected nearly all the crop to have been aborted but being Petit Verdot, it chose to do the opposite.  Probably because of the relatively bigger crop, it took 126 days to ripen, 4 days long than usual.

This also means the Moss Wood 2020 Cabernet Sauvignon brings to the discussion a slightly different blend, 90% Cabernet Sauvignon, 3% Cabernet Franc and 7% Petit Verdot.  The impact of the latter is visible in the wine, with more perfumed dark berries on the nose and a concentrated tannin on the palate.

Yes, we’ve painted a picture of a complicated year but we’d like to finish on a positive note.  None of the above had any negative impact on quality and the season 19/20 was near perfect for grape ripening.  The average temperature was a Goldilocks-like 20.4°C, the were no disease problems and we kept the birds at bay.  The vines easily ripened their crop and Cabernet Sauvignon picking got under way on 13^th March and with a median harvest date of 22^nd March, the vintage was 8 days earlier than average.