Episode 96      24 min 18 sec
The Wrath of Grapes: Wine Making and Climate Change

Viticulturist Prof Snow Barlow and Wedgetail Estate vigneron Guy LaMothe discuss the threats -- and opportunities -- that global warming poses for the wine industry in Australia and elsewhere. With science host Dr Shane Huntington.

"On top of that long term variability, we think there will be more extreme events. That means there will be more episodes of these heat related events. That means that vineyards will have to learn how to manage them." -- Prof Snow Barlow




           



Snow Barlow
Snow Barlow

Snow Barlow is Professor of Horticulture and Viticulture, and Associate Dean (Strategic Relationships)  at the Melbourne School of Land and Environment.

Professor Barlow's research interests include Plant Physiology, Environment (H2O,CO2,Temp) determinants of grape growth and wine quality, Water use efficiency, Australian Viticultural Terroirs, and Impact of climate change on Australian Agricultural Systems

Guy Lamothe
Guy Lamothe

Guy Lamothe is the owner of Wedgetail Estate. Located in the Yarra Valley of Victoria, Wedgetail Estate produces cool climates wines.

Credits

Host: Dr Shane Huntington
Producers: Kelvin Param, Eric van Bemmel
Associate Producer: Dr Christine Bailey
Series Creators: Eric van Bemmel and Kelvin Param
Audio Engineer: Gavin Nebauer

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The Wrath of Grapes: Wine Making and Climate Change

VOICEOVER
Welcome to Up Close, the research, opinion and analysis podcast from the University of Melbourne, Australia.

SHANE HUNTINGTON
I’m Dr Shane Huntington, thanks for joining us. The effect of climate change on our environment is no simple matter. For some eco systems the damage is substantial and will result in species extinctions and the destruction of entire habitats. For others changes in temperature, rainfall and CO2 concentration will provide potential advantages. In the wine industry there are some who have already seen benefits from changing conditions.

Viticulturalists, who have an advanced understanding of plant physiology and agricultural techniques and also a willingness to change their own personal preferences, can adapt their wine styles to suit climatic variations to the extent that high quality, balanced wines can still be produced. In this episode of Up Close we will be discussing the impact of climate change, both the positives and the negatives on wine production and wine quality. I would like to welcome to Up Close Professor Snow Barlow and Mr Snow Barlow and Mr Guy Lamothe each involved in the wine industry in different ways. Snow Barlow is professor of Horticulture and Viticulture from the Melbourne School of Land and Environment at the University of Melbourne. Snow has been with us before to talk about the global food crisis. You can hear him in episode 49 of this podcast. Guy Lamothe is the owner of Wedgetail Estate in the Yarra Valley of Victoria and produces a high-rated, cool climate wine, including a biodynamic Pinot Noir.  Welcome both of you to Up Close.

SNOW BARLOW
Thank you.

GUY LAMOTHE
Thank you.

SHANE HUNTINGTON
Guy, let me start with you. Everyone is aware of course that wine comes from grapes. But can you talk us through the process of how we go about doing this?

GUY LAMOTHE
Well first of all the vines have to be planted in the ground in the form of a rootling and the soil has to be prepared in accordance, prior to the vines going in. In other words the soil pH has to be calibrated and the proper nutrition in the soil has to be there. The growing phase for a vine prior to being productive is between three and four years. It is better to wait at least four years to let the vine increase in growth. Because the sooner you make demand on the vine the less its growth will occur. After four years then the small vintages are recommended – small yields should I say. From thereon the vigneron or the wine company will harvest the grapes and make wine with them.

SHANE HUNTINGTON
What sort of chemical changes are occurring during the wine production phase? What is actually happening to the grapes as they mature?

GUY LAMOTHE
Once the berries get crushed the sugar gets exposed to the yeast on the skin of the grapes and the yeast will automatically start chewing up the sugars and transforming them into alcohol. Also most winemakers in the commercial operations would induce a commercial strain of yeast to try to gain certain effects or quality into the wine.

SHANE HUNTINGTON
Snow, obviously there are a lot of things at play here in terms of what goes into the wine. Why do we choose wooden barrels in particular to hold the wine in for such a long period?

SNOW BARLOW
Part of the wine maturation process is a way to stabilise the wine. The French of course have led the way with using oak and after oak has been roasted the particular tannins there help to stabilise the tannins in the wine and enable that wine to be kept for a long time and to mature further. You do get some components of the oak in the wine. That is part of the allure of wine if it is made well. Just as an example, the ancient Mesopotamians did not have not have any oak so they used pine resin. If you have ever tasted the sort of  Greek retsina wines you can see the difference oak makes as regard to pine resin.

SHANE HUNTINGTON
Guy, there’s a vast variety of grapes and wines on the market. What has led tot his variety and how do you know what sort of wine you will be producing at a particular time?

GUY LAMOTHE
It is like starting any business. You do a business plan. You study the market and you see where the holes are, depending whether it is a corporation or a small producer. A small producer will make a wine that he is passionate about. A big corporation would do a business study and say, well we anticipate that in five year’s time there will be a big market for that type of grapes and that type of wine. Therefore, we’re going to plant those vines now.

SHANE HUNTINGTON
Snow, can you comment on the difference between your sort of drink now wines that we often see in the shops and ones that are recommended to be cellared?

SNOW BARLOW
It’s got to do with the complexity of the wines and how well they’re made and usually the use of oak as well. Drink now wines won’t have seen large amounts of oak. In fact they will have often not seen an oak barrel but only had oak chips, a small exposure to oak. It is mainly red wines that we cellar for a long time, but there are also some great wines that are also cellared. But those will probably have seen a little bit of oak as well. The chemical relationships with the flavours and the tannin process but also the oak compounds provide a stability and the way in which the tannins further develop. You get that smoothness that you get from old wines, which is actually a very good tannin structure, more of a condensed tannin structure. Rather than what you get in a young wine which is often a little raw and sharp on the edge.

SHANE HUNTINGTON
Wines that do not have their structure in them to a great degree, there’s really no point in leaving the bottle on the shelf, long term, if you won’t get those sorts of changes?

SNOW BARLOW
That is correct, yes.

SHANE HUNTINGTON
Guy, in terms of vineyards themselves, about how long do they last before they have to be essentially ripped up and replanted or moved?

GUY LAMOTHE
A healthy vineyard should start to be at its maximum production after ten years. They last up to – in a commercial sense up to about 35 to 40 years. Then after that the quality of the grapes might improve, but the yields will decrease greatly. Depending on the operation, some companies will decide to gradually replace those vines after 40 years or just set them aside as old vines and then charge more money. Basically the equation has to balance, because old vines produce a lot less grapes than younger vines.

SHANE HUNTINGTON
I suppose when you are setting up a vineyard, I mean this is quite a long term proposition, so you have to be somewhat sure of the environment you are choosing and the soils and the locale and the weather. There is obviously a lot that goes into that decision.

GUY LAMOTHE
There is, but when you plant a vineyard you really do not think 40 years ahead. You enjoy the process of planting the vine and the pleasure that everyday gives you. That is your currency for that time. Only big corporations or old families would think 50 years ahead really.

SHANE HUNTINGTON
You're listening to Up Close coming to you from the University of Melbourne, Australia. Our guests today are Guy Lamothe and Snow Barlow. Snow, let’s talk a little about wine regions and the sort of selection of them and how limited they are around the world. Presumably they are, unlike many crops, restricted to relatively small areas. Is that the case?

SNOW BARLOW
Yes, what we seek to do with wines is to match the particular, it’s not only grapevine but the grapevine varieties. Whether they be Shiraz, Syrah, Cabernet Sauvignon and Pinot will have different climatic adaptations. What we seek to do is to plant these in regions where they can ripen in such a climate that it is a mild climate, hopefully with cool nights but enough sunlight and enough warmth for them to produce the sugars they make. To optimise the flavours while maintaining some acid in the grape for the winemakers such as Guy who need to work with that. So we try and fit varieties to specific climatic environments. There is a circle around the world in the Northern Hemisphere and in the Southern Hemisphere where there are good viticultural environments.

SHANE HUNTINGTON
Guy, I’m assuming your wines in the Yarra Valley, which is in Victoria here, which is quite south are quite different to those that would be available say for example in Adelaide in South Australia, which is I guess, for our international listeners, to the west and north of Melbourne and Victoria. Is there any overlap or are they completely different?. Our climates are quite distinct.

GUY LAMOTHE
Yes Adelaide I think would be the equivalent, latitude-wise of central to middle Victoria. We are on the 37th parallel here. We are about a few degrees cooler than South Australia. Our wines are very distinctive. In South Australia they specialise in Shiraz. In the Yarra Valley, Chardonnay, Pinot Noir and Cabernet Sauvignon are the main varietals. All these plantings of Cabernet Sauvignon, Chardonnay and Pinot were done in the 1980s and 1990s where the climate was a lot colder than it is now. There was a lot more rain than now. At the moment I don’t know if there is any planting going these days in the Yarra Valley, because no one is certain about what’s going to happen with the climate.

SHANE HUNTINGTON
On that note we should talk a bit about how temperature does affect wine production. There are obviously to main issues with regards to temperature. One being mean temperature overall and then the seasonal variances or short term variances that you would see in temperature. How do these different numbers affect wine production?

SNOW BARLOW
You could say, given adequate moisture the grapevine runs on temperature. It will, what we call bud burst in Spring when the leaves begin to emerge from the buds. That is temperature driven, and the roots need to warm up before you get bud burst. Then depending on the ambient temperature you will grow leaves and develop the grapevine at a particular rate, which is temperature dependent. That of course dictates at what point at the other end of the season you will arrive at a point where the grapes have begun to ripen, after varaison and what sort of conditions are available then for the grapes to ripen properly in terms of sunlight, in terms of temperature and hopefully in terms of moisture. That is the basic temperature driver, which is the average temperature as you go through each month. Then there are a couple of variants. One is in the Australian context, and particularly more recently, episodes of what we call extreme heat. They can be damaging depending on when they occur. They can be very damaging in the ripening phase and perhaps a little less damaging earlier as, you know we had a very high temperature event in November 2009, which was actually right before flowering. In general the impacts, at least in the regions that I know of, Guy. were not too extreme. There were a few impacts in the Barossa Valley that I know of. But if as we had the record heat in Victoria, which is southern Australia, there were extreme damages to grapes in that time. That is dehydration, raisinning, and also loss of some of the delicate flavours and acidity from the grapes and making winemaking harder.

SHANE HUNTINGTON
Is there any way to protect against those extreme events?

SNOW BARLOW
We did a survey, my viticultural team, last year, which looked at ten wine regions in southern Australia which spanned the states of Victoria and South Australia and included the Yarra Valley, included the Mornington Peninsula, which are wine grape regions, one close the sea, the Mornington Peninsula, one an inland valley that does have some marine influences but not a lot. Then to Barossa Valley which is the icon in South Australia. We looked at damage across all those regions. There was some really extreme damage to areas that weren’t used to those extreme temperatures. They were what we call raisinning, which is essentially drying out of grapes. There are other grapes that were sunburnt, what we call, which is losing the pigments from the skin. The other big effect that occurred is the leaves were just burnt off. So it would have made ripening those grapes difficult after that because the drive of the leaves to produce sugar was not available. We think as a result of that survey there are certain ameliorative measures you might take to help you manage through those extreme heat events. That is what people need to do.

SHANE HUNTINGTON
If we talk for a moment about the longer term scenario. Guy mentioned before the difference in temperature between his vineyard and what we see in South Australian vineyards of being a few degrees. What sort of temperature change have we seen over the last four or five decades? Is it of a similar order?

SNOW BARLOW
Not quite that much. We generally think in southern Australia that we have seen warming post 1960 and that is 50 years now of somewhere between .7 and 1 degree. That is in the more coastal regions. In inland Australia there has been warming that has been as much as to 2 degrees in that time.

SHANE HUNTINGTON
Is that enough to actually knock vineyards out of production?

GUY LAMOTHE
Certainly. The long prolonged drought will eventually kill the vines. At the moment, I’ll take my vineyard for instance. We are in a dry area of the Yarra Valley, the north west corner, which is in the hills. We have got 30 per cent less rainfall in 2010 than we had say in 1996. So year after year the vines are getting less and less moisture in the root system. So they are becoming less and less productive, irrespective of the amount of fertiliser, care and attention, they need the fundamental and it is water. Without their yield dissipates and the canopy does not occur either. There are hardly any leaves growing. Because sometimes the leaves protects the berries from the sun. So when you get those big heatwaves like we had in February 2009, the canopies after seven years of drought were fairly thin, so they didn’t offer any protection to the grapes and therefore they all turned into sultanas.

SHANE HUNTINGTON
You're listening to Up Close coming to you from the University of Melbourne, Australia. Our guests today are Guy Lamothe and Snow Barlow. Gentlemen, the wine industry seems to be one that’s particularly susceptible to climate change as it’s occurring. Are there possibilities whereby we can benefit from these changes? Snow?

SNOW BARLOW
Yes, there are grapes that have perhaps been planted in too cold a region that will be advantaged. But similarly there will be some vineyards that maybe were just right or maybe were in the hotter side of where they might have been who will find it very hot. They will have a choice of either, depending on the variety, whether they actually change the style of wines they make. To give you an example, and Guy alluded to this. Shiraz is the sort of  variety that Australia has adopted is very adaptable to different temperatures. But it makes very different wines in different places. For instance we know the famous Barossa wines are what we call big Shiraz’s. They have lots of tannins in them, they are strong wines. The McLaren Vale is along the same lines. But if we come into Victoria here and we go to one of the better Shirazes around Victoria is the Mt Langi Ghiran Shiraz, which is grown at altitude, it is a finer grain Shiraz and it has a characteristic which we call white pepper. Instead of being a strong jammy Shiraz as the Barossa Shirazes are, this has finer white pepper characteristics. That is an example of two quite different wines but the same variety grown in very different temperatures. Not all varieties are as adaptable as that. Sauvignon Blanc for instance really doesn’t get the characteristics that we would like to see in a Sauvignon Blanc if you grow it in a very warm season.

SHANE HUNTINGTON
Guy?

GUY LAMOTHE
Yes, in 1996 we used to harvest our Pinot Noir at the end of March. Fro the last three years, 2008‑09 and 2010, we now have been harvesting our Pinot Noir in the last week of February. Basically we are talking here of a ripening five weeks earlier. That has significant effects on the wine as far as berry development. We have always thought and believed that the longer the grapes stay on the vine and they benefit from a cool nice Autumn, then there are a lot of nice complex flavours emerging into the wine. But in the Yarra Valley at the moment we are skipping all this with Pinot Noir and we are harvesting in the middle of Summer. The jury will be out to see if the quality of the wine is still there. But judging from our 2008 Pinot Noir it is one of the best ones we have ever done. It throws all the books out of the window as far as I am concerned.

SHANE HUNTINGTON
Yes. Snow?

SNOW BARLOW
Yes there are changes afoot. As Guy has just said and our research we have got several long term datasets from wineries in a whole lot of wine regions. The vintage has come forward in particular regions four to five weeks in the last couple of decades. It is more than a day a year basically. I think what wineries are thinking about and some of the large commercial companies, the corporate wineries, have moved into cooler regions. There is a bit of a land rush towards Tasmania which is the southern state of Australia. That is where they are going to grow their cool season Chardonnays, Rieslings, and perhaps Sauvignon Blancs and Pinot as well.

SHANE HUNTINGTON
Is there a concern amongst growers that we are moving towards a climate of greater instability as opposed to what we’ve probably seen in the past? Where long term patterns seem to be fairly consistent and predictable, whereas we are moving into a scenario where many of the events of say 2009 in Victoria will become more commonplace?

SNOW BARLOW
We believe in the climate science that yes we are moving there. Certainly in Australia the climate has always been quite variable. But on top of that long term variability we think there will be more extreme events. That means there will be more episodes of these heat related events. That means that vineyards will have to learn how to manage them. Already we are looking at people planting new vineyards perhaps will not plant north south. They may plant east west to help shed the sunlight. There are canopy management techniques that people use now. In other words pulling the leaves up to expose their grapes to get some sun exposure on their grapes. People are already leaving those leaves down on the western side to protect them from that hot western sun in those extreme events. There are a number of adaptation measures. People are, where possible, and where they can get the water, improving their irrigation systems. So that when we move into those extreme events if you have enough water at the beginning of the year you can construct a better canopy. But if you do not construct a canopy, it is a little sparse and many of us had that experience in 2009, your grapes are exposed. You have to work, not only in the week before the heat event, you have to work through the whole season.

SHANE HUNTINGTON
Just finally, we have talked a lot about sun exposure and temperatures and water, but do the relative amounts of CO2 in the atmosphere have any bearing on the growth of the grapes as well. Is that a factor you have to quite seriously consider at this point?

SNOW BARLOW
There has been a trend in Australian wine over the last 15years for the average alcohol content of Australian wines to increase by about 1 per cent. Now we are wondering what that is. There are a couple of things you might think about. One is that because it is warmer and they ripen quicker, that you might accumulate more sugar before they have accumulated the complexity and the flavour components that the winemakers feel it is time to harvest. The other thing is of course that may complicate] that is CO2. Plants are of course short of CO2 and as the CO2 rises by about 2 parts per million per year, we will get an acceleration of the capacity of the vines to synthesise sugar. That ripening period could be going faster in terms of sugar accumulation. That is something that we really do not have the measurements at present. In other crops there are massive field experiments with elevated CO2 in wheat crops and in trees. But it has not been done in grapevines. We are quite suspicious that perhaps elevated CO2 may be speeding the ripening cycle in terms of the accumulation of sugar in the grape berry. Then we will have to decide whether it has any affect on the flavour. So whether the flavours come along as well or whether they do not. Maybe Guy has a view?

GUY LAMOTHE

Well in the last three years we have found that the physiological ripeness of the berry occurred very early In fact that degrees of alcohol of say 11.5 to 12 [bome]. Therefore we have been harvesting our wine at those levels of alcohol and therefore we are producing lower alcohol wine. Our Chardonnay we harvest at 11 bome and the Pinot at 12. Five years ago we used to make a Chardonnay at 14 per cent alcohol and now we make a Chardonnay at 12 per cent alcohol. The style has changed completely. The wine tastes better for it.

SHANE HUNTINGTON
I think that is something we can all agree is a positive step forward. Gentlemen, thank you very much for being our guests on Up Close today. We wish you the very best of luck. I think many of us are affected by your efforts and we hope that they proceed successfully into the future. Thank you. Thank you.

GUY LAMOTHE
Thank you very much.

SNOW BARLOW
Thank you, Shane.

SHANE HUNTINGTON
Relevant links, a full transcript and more information on this episode can be found on our website at http://upclose.unimelb.edu.au. We also invite you to leave your comments or feedback on this or any episode of Up Close. Simply click on the “Add New Comment” link the bottom of the episode page. Up Close is brought to you by Marketing and Communications of the University of Melbourne, Australia. Our producers for this episode were Kelvin Param and Eric Van Bemmel, with audio engineering by Gavin Nebauer. Up Close is created by Eric van Bemmel and Kelvin Param. I'm Dr Shane Huntington. Until next time, goodbye.

VOICEOVER
You’ve been listening to Up Close.  For more information visit upclose.u-n-i-m-e-l-b.edu.au.  Copyright 2010, The University of Melbourne.


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