David Bruer
Region: ‘Temple Bruer’, Strathalbyn, South Australia (70 km south of Adelaide)
Commodity: Certified-organic grapes and wines
Farming area: 40 hectares
Rainfall: 490 mm average rainfall per year
Email: baywines@internode.on.net
Phone: 08 8431 0911
The two most important issues for us are climate change and water availability, which are related to each other. Both climate variability and long-term climate change are big risks for grape growers. We are changing our irrigation management, looking at new grape varieties and going carbon-neutral.
See what David has to say about:
- Later breaks, earlier harvests, less rainfall
- Managing extremely hot days
- Managing shifting harvest dates
- Changing varieties to handle warmer nights
- Treating water like it’s money in the bank
- Trialling new grape varieties from hotter climates
- Aiming for carbon neutrality
- Using weather forecasts for scheduling irrigation and harvesting
Later breaks, earlier harvests, less rainfall
Located in the Langhorne Creek district of South Australia, we grow 22 hectares of wine grapes on a 40-hectare property called ‘Temple Bruer’.
Temple Bruer is the largest dedicated certified-organic vineyard / winery business in Australia (certified A-Grade Organic by Australian Certified Organic).
We have two winemakers, Vanessa Altmann and myself, and a team of long-term staff, including vineyard manager Barrie Williams, general manager David Haeusler and my son Michael.
Being located near the mouth of the Murray River and Lake Alexandrina, both of which have recorded dramatic falls in water levels over recent decades, we are very aware of the issues relating to over-utilisation of water and climate change. Our weather is also influenced by the maritime climate.
We’ve had the property since 1973 and in that time, particularly in the last 15 years, we’ve noticed a number of changes.
The region used to be classed as a cool-to-medium grape-growing district. In terms of heat summation days it was the same as Bordeaux in France, so it was relatively cool and a good deal cooler than McLaren Vale and the Barossa.
We have observed that the breaks to the season are getting later.
The big changes are in harvest days. When we first planted our verdelho 15 years ago, we picked it at the end of February, with 22-25 February being common harvest dates. In 2010 we picked it almost a month earlier on the 28 January.
In 2008 we recorded our lowest rainfall ever with just 152 mm of rain for the entire growing season. This is extraordinarily low rainfall for our district and prior to that year the district average was 400 mm.
Managing extremely hot days
Our winery normally crushes 500 tonnes of grapes each season.
In the last three years (2007–09) we’ve only crushed between 300 and 350 tonnes due to the particularly savage drought and a couple of serious variations from our normal climate.
In spring of 2009 we had a single day in early November that reached 44 degrees Celsius, about a week after peak flowering.
That extremely hot day caused us to lose about 90% of our crop of merlot and similar percentages of cabernet and grenache.
Our verdelho, of which we needed every berry we could get, was practically decimated and we harvested less than 10% of our normal crop.
Our shiraz was not affected and our riesling yield was only knocked down a bit. Different grape varieties behave differently under extreme heat.
The only way to prevent such damage occurring again is to heavily water the vines the night before to prevent them from getting water stressed during the heat of the day.
We are planning to build a larger dam and install irrigation infrastructure so that we can water all the vines at once and get the soil-moisture levels up high if we know a heatwave is coming.
Managing shifting harvest dates
An increasing variability in climate is also impacting on the date of first coloured berry at Temple Bruer.
The date of the first coloured berry is important because that tells us when it will be time to harvest. There’s a standard time interval of 61 days, plus or minus 2 days, from first coloured berry to harvest.
Not only is the date for the first coloured berry, on average, earlier, but the date is varying more.
First coloured berry used to occur between 5 and 9 January, but now it occurs anywhere between 1 and 19 January. So not only has it shifted, on average, to an earlier date, but the variance has become much wider.
It is the increasing climate variance that really worries me about climate change.
Changing varieties to handle warmer nights
Grapes are very sensitive to heat summation, which means that they express characteristic flavours only at certain ranges of heat summation.
Riesling, for example, likes a fairly cool ripening period with cold nights.
We have been recording night-time temperatures that are significantly higher than they used to be in our region.
If night-time temperatures continue to increase under climate change, we probably only have 15 years left to successfully produce good riesling in our region.
Shiraz is possibly doomed too, but will probably keep yielding good quality grapes for another 25 to 30 years.
We think the merlot vines will stop producing good quality grapes a bit sooner than shiraz.
Cabernet is surprisingly tough. Even though it normally is best at cool-to-medium temperatures, it will still tolerate quite high day and night temperatures.
It’s not all bad though.
We have one variety that we have been struggling to get ripe. About 5 years ago we were thinking about pulling it out because we were only getting it ripe about once every 2 years. But in the last 5 years we’ve got it ripe every year.
That may be a small win but, overall, the losses far outweigh the wins.
Treating water like it’s money in the bank
Temple Bruer was one of the few properties in the Langhorne Creek region that did not sign up to the irrigation scheme to access water from Lake Alexandrina. It was expensive to convert and we had a good system here already.
A large aquifer runs beneath our property. We treat it as a bank where we store water in good years and we draw it out in not-so-good years.
We are licensed to take water from the Angas River which borders our property. During winter we draw water from the river and pump that into the aquifer for when we need it during spring and summer.
In 2010 we pumped 81 megalitres into the aquifer. We probably only take back about 70–75% of what we recharge.
Trialling new grape varieties from hotter climates
The capital investment that we have made in the vineyard is massive – about $50,000 per hectare.
We can’t pick up and shift the vineyard to a better climate. But we can keep most of the infrastructure and simply replace vines with more appropriate varieties. But that’s a slow process as it takes years to establish a vine ready for harvest.
We are looking at some new varieties from hotter climates, particularly southern Italy and Sicily. We have identified about a half a dozen different whites and reds. We’ll plant a couple of rows and see what we think of them.
Aiming for carbon neutrality
If we want the Australian wine market – in fact, any wine market – to take us seriously, we have got to achieve greenhouse gas neutrality in the next couple of years.
We intend to do it in a proper way. We would like to do it without buying carbon credits, but it will take years to get there so we have worked out a plan.
We will pick the ‘low-hanging fruit’ first, for example:
- using lightweight bottles, which also saves on transport costs
- cutting out all air freight
- generating our own green power
- shifting from freon-based refrigeration to ammonia
- revegetating more land
- increasing soil carbon sequestration by reducing or eliminating cultivation
We will have to buy some carbon credits initially as we can't do all this immediately.
Planting native trees at the vineyard will offset 15 tonnes of greenhouse gases per year, so they are a valuable asset for us in cutting our carbon footprint.
If it is humanly possible for us to not buy any carbon credits, then we will do so. This may be a number of years away.
Using weather forecasts for scheduling irrigation and harvesting
We use the Bureau of Meteorology’s data extensively for planning our irrigation schedules and harvesting.
We harvest all our white wine grapes at night; we want the grapes to be as cool as possible because we are trying to minimise our refrigeration demand. The Bureau provides excellent data on night-time temperatures.
We want some of the red wine grapes to be warm, so we pick them during the day and we use the Bureau’s forecasts to choose the right day.
We have a window of about 5–7 days to harvest most varieties, which gives us a fair bit of flexibility and the ability to choose the best day to harvest.
We think the Bureau is providing good information and if they can provide us with even more data, that would be terrific.
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Interview date: 18 June 2010