Bordeaux climate change Stephane Dupuch


While we were tasting with Stéphane Dupuch at Chateau Sainte-Marie, a conversation began about how winemakers are responding to the challenges they are facing from weather extremes as a result of changing climate. Stéphane's answers are candid and insightful in giving us a snapshot of the current situation.

Secret Sommelier (SS): What measures do you currently take to respond to climate change challenges?

Stephane: So we have 3 different weather stations. These are run with software called EPI, inputted with what we have from our weather stations on the estates.

The software calculates if you will have a development of mildew, rot, botrytis. With this, they can give you a percentage of risk. For example, the risk of mildew is very very high. And you then decide what you want to to do. But you decide. They don’t tell you that you have to treat. The software just gives you the percentage risk.

You watch the forecast and decide that if the forecast is wet for the 3 next days, you decide to treat or not.

SS: How accurate is the forecast?

Stephane: Every time.

SS: So 100% accurate?

Stephane: Yes! We are a group now and what is important is that we exchange and share our information. We have a group of 150 meteorological stations, not only in the Entre-Deux-Mers, but also in Saint Emilion, in Medoc and Sauternes. 

We exchange the data and you can also put what you have seen in the vineyards. (EG) I have some mildew in this parcel because this parcel gets much more water. So we know how many millimeters of water we get in this parcel. For example, we have a spot called Le Jardin, which is just here. In this space, it is 3 hectares, we have a lot of mildew here. We have seen that we have to [deploy] downy [mildew] treatment 2 days after the rest of the estates. During these days we have some water and so it is different.

SS: Does this help with detecting hail?

Stephane: No, no. For hail, we have what is called MeteoFrance. So they know when the hail cloud is forming and they call you in the morning, or they send a mail, to say that ‘you have a risk or hailstorm, and there are some big clouds forming. They are going to charge on the water and you have a big risk of hail.

But you cannot protect.

SS: So you have analysis but in terms of solutions, how do you deal with each problem?

Stephane: With frost, you don’t have any protection. You just pray! Hail, this is almost the same, because, this is not the same as in Burgundy. In Burgundy they have canons. They have developed it because they have small vineyards. It is only 30,000 hectares. But Bordeaux, all the vineyards are 120,000 hectares. 

So you have to imagine that this is so big to protect with canons, it means that we need maybe, 10,000 different canons. Even with this I am not sure…

SS: It would be like World War 2, fighting against nature!

Ha, yes! So we don’t have so much protection.

SS: So what controls or solutions do you have?

Stephane: The only thing we can control is whether we treat or not. If you expect good weather for ten days without any [rain] and the pressure is very low for mildew then you don’t treat. But if you have big pressure, if you are not sure of the forecast for the weather, then you must treat.

So, this all just helps you to decide whether to treat or not. But it is completely different to what my father used to do. My father (and not only my father) used to say that ‘every 10 days we have to treat! Every ten days! 

So from the bud bursting to the flowering, every ten days, we take the tractors and we treated. Nowadays, we reflect on whether we have to treat. It is completely different.

SS: It is a heavier question?

Stephane: Yes, it is completely different. Do I take the risk to treat or not treat? If I don’t treat and the forecast is not good for the weather, then I can decide to not treat. If I then have 3 or 4 days of rain then it can be a problem, because my percentage risk of mildew, for example, will be very very high and I will have a risk of contamination.

SS: Have you heard about the trials going on here in Bordeaux using algae to fight mildew?

Stephane: No, but I think the next question will be to find a new process that is much more respectful to treat with. It might be algae or it might be different but what we used to do during the last 50 years has to change.

I think there is always a risk to forbid some chemicals. In Europe they want to stop the use of Roundup, a herbicide. It is one of the most well-known herbicides used all over the world, not only for vineyards but for everything. It’s made by Monsanto. They want to stop it but I think the risk is that they don’t have any other solution. So you can stop selling it but you have to find a different solution.

For me, the future won't be with treatment. It will be to help the vineyard protect itself.

You have some crossing of vines that are strong against the rot and the mildew and they can fight 

I think the big difference between the wine of today and twenty years ago is not just due to global warming, it is also due to a different way of vineyard management. 

SS: You mean of philosophy?

Stephane: Yes. To compare, in 1982 the yield in the appellation was 80 hectolitres per hectares. Nowadays it is 50HL. So we have nearly divided by two. So there is a huge change between a vineyard of 50 HL and a vineyard at 80HL. 

SS: It is amazing isn’t it, how, obviously, the winemaker has changed how they think about what they are producing, or the style of what they are tasting and that this then reflects in the consumer who comes back and makes their choices. It all feeds back into the one that you get here? People seem to like fresher wines….

Stephane: But it will be challenging with global warming to make fresh wines in Bordeaux so that is why it is important. I think I told you in London that it is important for me to have very different types of grapes because, like cabernet franc and cabernet sauvignon, it wasn’t really ripening 20 years ago in the vineyard but now, every year, cabernet franc is ripe!

So it is important also to keep these different grapes. I am not saying that we have to plant some mourvèdre here but it is important to have different types of grapes.

This is also the story of our region, the story of the Entre-Deux-Mers region is to have different grapes.


Stéphane Dupuch is the of Château Sainte-Marie and was also the President of the XYZ. Nick Breeze and Natalia Baloghova represented Secret Sommelier.


Follow us on social media:

Secret Sommelier on TwitterSecret Sommelier on Instagramfacebook 001linkedin 001youtube 001

COPOUT Book by Nick Breeze

Climate change podcast

We use cookies to improve our website and your experience when using it. Cookies used for the essential operation of this site have already been set. To find out more about the cookies we use and how to delete them, see our privacy policy.

  I accept cookies from this site.
EU Cookie Directive plugin by