Terroir: The science behind the soil.

Terroir when discussing wine can be a controversial subject. Not only does the definition vary from country to country or person to person but opinions as to its influence on the final product and just how that influence happens is also open to debate.

Does the definition include only soil and topography? But then there’s climate and microclimate, and what about the role of man as a grape grower and even as a wine maker – how does that fit into the definition?

Bdx micro climate
Does the definition of terroir include the maritime climate of Bordeaux?

Wine being defined by the place it’s grown may be a European or old-world concept, but things are changing. Although most European wines are still very much about the place, it is the foundation of the appellation system after all, the influence of the wine maker (or consultant wine maker) is playing a larger part. Famous wine makers and consultants now sign off on wines around the world. Interestingly in the ‘new world’, it would seem the opposite is happening. Whereas as once the role of the wine maker and wine-making techniques was paramount, the notion of terroir and its influence seems to be gaining ground (pun intended). Could it be that the new and old wine worlds are reaching a consensus?

Where does the influence of terroir end and wine making begin? The wine cellar in the heart of the terroir at Chateau Feret Lambert in the Entre Deux Mers
Where does the influence of terroir end and wine making begin? The wine cellar in the heart of the terroir at Chateau Feret Lambert in the Entre Deux Mers

In many regions it’s all about the place, Bordeaux very much so, Burgundy even more and on my recent visit to South Africa, Haskell, Jordan and Klein Constantia the identification and isolation of different terroirs was at the forefront of every conversation.

The Terroir wall at Ellerman House Hotel in Cape Town show cases the variety of South african wine terroir.
The Terroir wall at Ellerman House Hotel in Cape Town show cases the variety of South african wine terroir.

With improved techniques such as measuring soil resistivity, satellite technology (and good old fashioned digging of holes), the notion of terroir is becoming more precise. In Bordeaux, recent investment in the cellars has all been about smaller and smaller vats; each vat destined to receive the grapes from a specific plot as a better understanding of terroir leads vineyards to divide their land into smaller and smaller units.

Plot by plot identification at Chateau Rauzan Segla in Margaux
Plot by plot identification at Chateau Rauzan Segla in Margaux

This has always been the case in Burgundy; here you can stand at certain crossroads and almost touch three or four different appellations. Unlike Bordeaux with our blends, in Burgundy they only really use one red varietal, Pinto Noir, so the personality of different plots has to be down to the place; the terroir. Wander through a Burgundy cellar and the many barrels may each contain wine from a different plot, each one a different appellation. It’s not unusual to see 6 or more different appellations in one cellar, all grown and vinified by the same team.

Not so in Bordeaux. We blend varietals but we also blend terroir, all those row of barrels from the different plots in a Bordeaux cellar will end up being blended together in to one, two or maybe three different wines. So why cultivate and vinifiy each plot of land separately if you are going to end up blending it all together?

Two reasons: As we have a more precise understanding of the terroir it allows for a better choice of grape varieties best suited to each plot, to produce a better wine. But there’s more to choose from than just varietals. It’s also the clone of the varietal and the rootstock. As Bordeaux vines are grafted, the grower has a choice of rootstocks that suit different soils, either limiting or increasing the vigour of the plant. But these choices are only made every sixty or seventy years or so when replanting.

Old vines, well adapted to their terroir?
Old vines, well adapted to their terroir?

The second reason is more about how we treat these plots year on year; how the soils are ploughed and fertilised, how the vines are pruned, trellised and trimmed and the all important harvest date. Ripeness can vary enormously from plot to plot depending on soil composition; clay soils tend to be cooler, gravel soils warmer, sun exposure can also change – it all adds to the terroir puzzle.

How does working the soil influence terroir.
How does working the soil influence terroir?

So coming back to that definition of the term, what of the role of the grower? Does terroir remain the same or has man changed it? In regions like Bordeaux where grapes have been grown since the middle ages one suspects that yes, man fiddling about with the terroir since they first started planting vines has had an effect.

Man has had an influence on terroir in historic vineyards - such as here in Sicily
Man has had an influence on terroir in historic vineyards – such as here in Sicily

A key example is drainage. Water is a key element in terroir: the soils’ ability to retain or drain. While many vineyards of the world are suffering from drought, in Bordeaux’s maritime climate we tend to have too much water. Drainage is a Bordeaux obsession, a lot of time and money is invested in insuring good drainage either natural or giving it a helping hand. The famous draining of the Medoc peninsula by the Dutch in the 17th century gives the site we know today – very different from it’s original ‘terroir’.

Drainage ditches in the grey clay of Chateau Cheval Blanc in Saint Emilion
Drainage ditches in the blue clay of Chateau Cheval Blanc in Saint Emilion

Then there is fertilisation, composting, ploughing and chemical treatments; continued over hundred of years surely this too has to affect the sense of place? The return to a more natural and eco friendly approach to vine growing after the excesses of the 70s is perhaps also a desire to return to a more real sense of terroir?

Most wine drinkers may not know or care what terroir means; they may choose their wine as a function of one or several grape varieties. But those of us who are lucky enough to taste wines from different places, and people, will recognise that the same grape variety can produce many different styles of wine depending upon where it is grown.

In Bordeaux we generalise by saying a right bank Saint Emilion is Merlot driven and a left bank is Cabernet Sauvignon driven. But look closer and we see this benchmark differentiation is not always strictly true. For example in the Medoc, in the Moulis and in Listrac appellations, you will find properties here that have a high percentage of Merlot, but they still taste like a left bank wine, they still have the taste of the place. It’s important that it does, one of the categories looked at when wines are assessed for their appellation certification is indeed typicity, this sense of place.

So you can start to see the importance of understanding terroir. If this has whetted your appetite for the subject I can recommend two books, that I have mentioned in a previous post,  to help you take the idea further.

Charles Frankel is a French, wine-loving geologist. In his book Land and Wine: The French terroir, he paints an fascinating picture of the terroirs of all the leading French wine regions and how they came to be. He tells a story that starts 500 million years ago and, instead of dry science, the subject matter includes not just the rocks but how they got there and how other historical influences give us the vineyards we have today.

Land and Wine by Charles Frankel
Land and Wine by Charles Frankel

Jamie Goode, is a leading British wine blogger under the name The Wine Anorak, in the latest edition of his book Wine Science, the application of Science in Wine Making he has included a chapter on how soils shape wine as well as the original chapter on terroir.

Wine science by Jamie Goude
Wine science by Jamie Goode

It addresses the question of exactly how terroir influences the taste of the wine in your glass. Or does it? Jamie is first and foremost a scientist and he brings this rigour to the subject of vine growing, wine making and wine tasting. In our more romantic vision of wine we often forget it is a science, he manages to remind us without losing any of the passion he obviously has for wine.

A little knowledge may be a dangerous thing, these books might create a thirst for more, consume with moderation.

One Reply to “Terroir: The science behind the soil.”

  1. Dear Wendy,
    Always interesting to read your posts as they are varied, interesting and well researched!
    A propos your latest post on terroir, I attach our Chateau Biac map which we have on our website showing just that : diversity of terroir…and defining the blocks according to geological identity. Just in case you do something similar again…for the record, Steven Spurrier described Biac’s terroir as “Burgundy in Bordeaux “ in his June article “Deserving Heroes”. It is according to many professionals in the region, the only property with such geological diversity on such a small surface!!! An astonishing mosaic of both right and left bank type soils side by side on only 9 hectares (http://www.chateaubiac.com/-the-estate-.html?lang=en)
    Keep well
    The Biac ladies!

Leave a Reply

Your email address will not be published. Required fields are marked *

Latest Articles


Notice: Undefined index: HTTP_REFERER in /home/sites/reasonablygood.com/public_html/dev/insidertasting/005805/wp-content/themes/reasonablygood-insidertasting/single.php on line 120
back