Wine’s God Particle – The Science of Terroirism


                                     water retention data sets on a vineyard one of the earliest scientific tools of terroirism

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                                  Beauty and the memory of years of success and failure has been the traditional method

Brian Crosser is a cutting edge scientist, steeped in the academic rigour of the hard sciences, the natural sciences as they used to be called. He is also a former Decanter Man of the Year, winemaker, consultant and founder of the famed Petaluma Estate in Australia. Former Chief Winemaker of the entire Hardy’s Wines group in the 1970s he planned and conceived a new vision for Australian wine that has now come to pass.

If anyone deserves the title, Guru, then Brian Croser is that candidate.

Dozens of the world’s leading winemakers studied under him at Riverina – Charles Sturt University, from the 1970s onwards including many who like Martin Shaw of Shaw& Smith, the makers of Australia’s current best Chardonnay, also worked for a decade studying ujnder him in situ at Petaluma.

In 2004 having been the subject of a successful hostile takeover of Petaluma by the giant Lion Nathan drinks group, Croser along with his family founded Tapanappa in Australia and another winery in the US.

His key breakthrough in science and wine was to map out, in meticulous detail, the actual, not the supposed or agreed best confluence of factors that make for the right spot to plant vines.

He in a word, found, the God Particle in Terroir.


He has been refining, perfecting and experimenting ever since and without a moments self conscious pause refers to his wildly complex data sets as The Matrix

Mountain High, River Deep

Now, Brian Croser has become a feature of South American wine working as a consultant with the Santa Rita Estates wine group. For the second year running this has resulted in a no holds barred scientific conference on South American Wines, with Croser at its heart.

It is a refreshingly scientific and collegiate affair with half a dozen different, and competing,  wineries taking part, along with winemakers, consultants, regional experts, environmentalists and workers from all parts of each of the companies. Into this mix Oz Clarke, Jancis Robinson, Steven Spurrier now looking incredibly like Alan Rickman who played Spurrier in the film Bottleshocked and Tim Atkins MW the feisty co-Chairman of the International Wine Challenge.

Like any good academic conference abuse came with dripping innuendo and terribly, helpful, tiny, data corrections.

Croser and Atkins crossed swords on the issue of ‘dead fruit’. A style of wine Atkins accused Croser of seeming to praise. It seemed a mistaken impression by Atkins but I watched in growing fear of a more direct riposte from Croser as his face bloomed purple and he spoke ever more quietly, over the top of his glasses.

Croser, like all Gurus and I dare say driven scientists is not an easy man to work with. Most former students and colleagues use the phrase, does not suffer fools gladly, interspersed with the even more frequent statement that when Brian Croser has his data well secured in his own mind, you would want to be very, very sure of yourself to offer other thoughts.

Perhaps the greatest evidnce of this iron and self confident will is that the muti-million dollar behemoth of Lion Nathan after taking control of his company against his will, eventually fell in line, with Croser, leaving him in full control  of Petaluma and adopting a new policy of autonomous units within their vast empire of wineries.

So, his keynote address was widely anticipated and, was superb.

Through minute analysis of the vine and geology, Croser and a generation of oenological scientist from Universities in Australia, Bordeaux, California, Santiago, Chile  and Germany have essentially unravelled the wine equivalent of the exploration of the world of sub-atomic particles.

Finding the right place to plant Cabernet Sauvignon for example is now, under this methodology a game of science not art.

This has meant that Croser personally pioneered the shift from the, its only dirt and if we irrigate and fertilise we can grow anything anywhere school into a genuine scientific terroirism.

Croser is often called a Terroiriste, and does seem to enjoy the title.

Croser pioneered Cabernet Sauvignon and Merlot in Coonawarra, Riesling in Clare, and Chardonnay and Pinot Noir in the Adelaide Hills.

Today he can most frequently be found in 10 and 15 foot deep holes across Chile and Argentina, and this is where his consultancy expertise is being put to superb use, fine tuning the potential of Chile and indeed Argentina into a fine wine, world class leading reality.

Cabernet Sauvignon is a good way to begin looking at his theories.

The Green Gene and Calibrating Greatness

Cabernet Sauvignon is not an ancient grape, it first really surfaces as a recognised entity somewhere in the early 18th, perhaps late 17th century. As a grape species it emerged sometime in the period just before this as the improbable offspring of the red grape Cabernet Franc and the white grape Sauvignon Blanc.

At that time farmers would often plant red and white varieties together, sometimes to be harvested together, sometimes harvested and produced as red and white wines. Vineyards were wild affairs and reproduction was sexual with many thousands of different clones. Today vineyards are made up of identical individuals, clones, and reproduction is asexual, so we do not get the variations, crosses and happy accidents of a field of endlessly varied clonal individuals.

So, from long study Croser suggest in relation to Cabernet Sauvignon that “it shares with Merlot and Carmenere their shared propensity to retain the green character of Isobutyl Methoxy Pyrazine.”  or IBMP to its friends, who are not legion. “In cool and damp years and cool and damp soils where vigour is too great, and canopy shades the fruit, the grapes retain IBMP, which reflects in the wine as an herbaceous, tomato vine, green character.” Says Croser.

The sequence of ripening according to Croser also affects “The propensity to retain IBMP, which together with phenol builds up in the lag phase of berry development before veraison.” In other words, veraison which is when the grapes (and tomatoes) change from all green to their final grape colour, purple, blue red in the case of Cabernet Sauvignon is key to finding greenness despite any other factors like good weather in any particular vintage.

Mirco-Climate and micro-geology are going to play their part here. The geology is going to have to be rocky and free draining to avoid damp which will only encourage the vine. It will have to be the kind of soil that can also both stress the vine and keep it warm.

Essentially shattered, fragmented rock, hard rock too raised up on an underlying bed, stones on a damp proof layer if you will. We can most easily get this if a hard mountain were ground down by glaciation and washed into a nice bowl by river action.

Think, the Pyrenes ground down and spilling its fragmented detritus south into Navarra and Rioja, but best of all, north into the Gironde basin. The entire Medoc, a gravel pit of waste from the Pyrenes created over millions of years.

This is what Croser is in holes in Chile looking for, and he has found many matching sights for Cabernet Sauvignon across the world that mimic the quaternary gravel soils of the Medoc including the clay loams on a quaternary Limestone ridge, essentially Coonawarra, The Gimlett Gravells in New Zealand and excitingly in Chile in several ”Alluvialrock and gravel benches and colluvial fans of the Maipo Alto and Aconcagua river tumbling down from the Andes in Chile” says Croser.

But he is not looking at this generically he is seeing this only in tiny spots.

This is mainly because “We have to now take all the geology and general climate and place a Matrix of other significant factors over this.” Says Croser.

“While climate is vital, and temperature is at the core of this, altitude, distance from cooling factors and rainfall are equally important. But the thing we really need to look at is Diurnal Difference.” Says Croser.

Diurnal temperature is a range figure that tells us the distance in degrees from day to nightime temperatures and has never been overly fretted about.

The previous scientific god, still enthroned is Heat Summation.

Heat Summation is the cumulative heat a plant can expect to receive over a growing season, however this is now sidestepped by hipster to foreground GDD or Growing Degree Days, this is the number of days that are effective for growing, potential more accurate but wildly complex to work out because you need to go, hour to hour and degree by degree in your analysis.  So the Units of GDD are in thousands, but immediately fascinating.

We Irish wine lovers have been singing the praises of Chilean Pinot Noir for a few years now, but it has always been a shade away from Burgundy Pinot flavours.

But look at this, Casablanca a current source, San Antonio, not.


Region                        GDD Units     Diurnal Range           Maximum C   Min C

Casablanca                  1245                17.2                             24.5                 7.3

San Antonio                1145                10.6                             20.7                 10.1

Burgundy                    1172                11.4                             21.2                 9.8

Its pretty clear that if we were equipped with Croser’s data we would have gone straight for San Antonio and planted Pinot Noir, it is a much better fit according to these figures than Casablanca which is both too hot and too cold, its swing in temperature the Diuranal range is doing something else however according to crosser.

“The vine, shuts down under 10 degrees.” Says Croser, we can see this clearly, the theory used to be that therefore we need not worry if the Diuranal range as large because no damage was being done as the plant was dormant. But the issue is this, in essence the plant will continue to tick over in Burgundy, over night.”

So, even though Burgundy and sites like it seems under powered heat wise, and curious climatic anomalies which are then described as privileged sites that the word, terroir gets attached too. The scientific truth is that its miracle status, and therefore its uniqueness was due to an essentially unmeasured or unappreciated piece of data.

Fill in the night time elements, the crucial post 10 degree point and we have the explanation, best of all, we can now begin to look for the exact match for our Pinot Noir or our Cabernet Sauvignon. Not only that but it can be ultra fine tuned to find actual, privileged sites that offer the holy grail of a fine wine site.

This chart is fascinating too

Region                        GDD Units     Diurnal Range           Maximum C   Min C

Pumanque                   1513                14.2                             21.9                 10.1

Coonawarra                 1399                14.4                             23.8                 9.5

Bordeaux                    1485                11.4                             22.6                 11.2

From this it is clear that the rising star in Chile should be Cabernet wines from Pumanque with the heat GDD of Bordeaux and the Diurnal range of Coonawarra, the prospect of a savoury but muscular cabernet giving us the best of  both the other class leading regions is exciting.


Using Science to Seek The Sustainable

Not alone does the idea of a data set driven exploration of the Chilean landscape bring up exciting possibilities for wine lovers, best of all is that it should promote a better, green and sustainable approach to viticulture which has up until now in many New World locations been a thirsty and rather blunt agricultural instrument.

“Using this kind of matrix of data, we can literally dial up, the exact locations we need to examine planting particular vines in and with accuracy that can be beneficial.” Suggested Croser

The accuracy issue is interesting, much of the waste surrounding viticulture is about irrigation, but if you could tailor your sites exactly, before planting every vine randomly to see which works, we can move to a much more sustainable vision of agriculture.

The reason people persisted with unsuitable vines in the wrong area thus necessitating fertilisation, irrigation and a myriad other interventions was twofold, firstly a belief amongst Australians and US wine growers that they should in any event impose on the land anything that could be grown, which was therefore everything if you had the money, rather than asking what, should be grown.

Secondly, vines took years, decades to show if they had worked in a region and people were reluctant to uproot and start again, naturally. Now with the Chilean scientific revolution, fore fronted by a wily Australian Guru, things look like they are about to change.

Almost any wine lover, with mouth watering, will want to follow the new Matrix Map of the world and see every matching privileged site planted and on our shelves. The blind faith era is over, long live Leyda Valley, San Antonio and Pumanque and the Wine Matrix.