It seems to make sense that the taste of a wine reflects where it is grown. After all Barossa wines do have different aromas and flavours to Tasmanian wines. The French use the term 'terroir' to describe the differences that refect the sense of place where the grapes are grown.

While it is possible to agree that terroir must exist it is hard to agree on exactly what tastes it does impart and whether it means much more that saying this is a cool climate wine and this is a warm climate wine.

Currently the idea of terroir is used by a great number of wine regions across the globe to try to illustrate their difference. Marketers talk of vineyards being on ancient rocks and soils, of landscape settings that are so difficult for cultivation that only the hardy vine can grow, of unique weather patterns without which the grapes would never ripen and even of mysterious indigenous yeast strains.

Thinking about the tastes that can be attributed to terroir made me ponder the great number of other tastes that are introduced into wine in the vineyard and when it is made and which have nothing to do with terroir. Is it possible for the 'taste of terroir' to show through these masking influences?

And another layer of problems occur during tasting as it is a very subjective business.

Recently Tim Atkin writing in the English Observer (5/2/06) touched on the topic of terroir and ended by saying; "Wherever it occurs, terroir is nothing more, or less, than a sense of place. Some wines have it, some don't. Those that do are readily identifiable in a blind tasting, at least to a wine professional. If anything, the internationalisation of wine styles - and the fact that wine is better made than ever - means it is harder to tell the wines of different regions, let alone different vineyards, apart. These days, terroir happens everywhere - and nowhere."

I'm not entirely sure what he is saying except that it is a confusing topic and that good wines are said to show terroir.

Listed below are some of the factors that can affect the flavour of the wine that are additional to those that are said to be due to terroir. There are many more. Some of these topics could be greatly expanded and additional comments are given for a few.

In the Vineyard

The orientation of the vines to the prevailing weather and sunshine.

The clonal stock of the grape variety and does the vineyard have multiple clones.

The root stock of the vines.

The vineyard-vine trellising method.

The pruning method used.

The tonnage per hectare picked.

The time of picking for optimum time of grape ripeness. And we know the furore this has created in Bordeaux where ultra low yields and very ripe grapes seem at odds with the traditional Bordeaux taste.

Fermenting the Wine

Pre soaking of the grapes before fermentation.

The degree of pressing of whites before fermentation.

Fermentation. The fundamental taste change to grapes is of course from fermentation. A few wineries that consider themselves purist let the natural yeast of the grape bloom and those in the winery take over. This is called 'wild yeast fermentation'. Other winemakers prefer to control the fermentation with the addition of a known yeast culture. Whatever is used the additional tastes introduced to the flavour of grapes are profound. And besides yeasts a great many bacteria species are involved in this brew.

What happens during fermentation is a vast topic. A recent report from New Zealand gives some idea of how flavours are created and can be manipulated. This work involves the capacity of yeast to convert thiols into volatile compounds that are seen by consumers as desirable in sauvignon blancs. These quotes are taken from an article that appeared in Decanter.

"Part of Marlborough Sauvignon's success lies with the volatile thiols, such as 3MH, 3MHA and 4MMP, which complement these methoxypyrazine characters. Until the mid-1990s little was known about these thiols, generated from the interaction of precursors in the grape with yeasts during fermentation and responsible for cat's pee and passion fruit notes."

'Thiols have much potential for manipulation – only a small fraction of the precursors get converted,' says Professor Richard Gardner, who heads the programme as well as its yeast research.

As well as looking at how efficiently commercial yeasts convert thiols, the research could see the development of new strains with higher conversion capacities. This would enable winemakers to tweak sauvignon styles towards certain flavour profiles, selecting yeasts to enhance or suppress chosen characters."

Post fermentation soaking of the grape pulp and wine.

The degree of pressing of red wines.

The effect of ageing in oak whether it is new or previously used oak; and this is of course a huge factor in the final taste of a wine.

All manner of post fermentation flavour builders from lees stirring to micro-oxygenation.

Bottling and Post Bottling Effects and Tasting

Acid adjustments of whites at the time of bottling.

The closure whether it is cork or stelvin or some other.

The effect of the type of glassware selected for tasting.

The genetic differences of the tasters. This is a real conundrum as research is showing what you and I can see in a wine will differ because our sensory genes are not the same. When this is more generally appreciated it will start to invalidate a lot of tasting results.

The temperature of the wine and the effect on taste.

Strange Anomalies

Then a short list of odd things that are talked about as altering tastes.

The effect of altitude on taste is often reported by airline travellers. I have no idea why this would be so in a pressurised plane.

And how about this reference from Julian Jeffs book on Sherry: "Owing to the difference in climate, wines that taste austere in Jerez taste even more austere in the northern countries, and the further north you go, the more you notice it; you can even tell the difference after a journey from London to Edinburgh."

And while on the matter of sherry it is not terroir that makes the special taste of manzanilla, the famous wine of Sanlucar de Barremeda but rather the moist sea air which changes a fino to a manzanilla .

Anyway this list is by now long enough to see that while the sun may ripen the grapes, the flavour in the bottle has come from many other directions and this is before each taster sees what they want to see in a glass.

Whether the 'terroir' taste can poke through all these masking influences is very hard to say. While many wine makers particularly French winemakers are adamant that their wines reflect the terroir it seems more and more that what they are saying is; when a good or great wine is made it must reflect the terroir. This is not the same thing at all.

In an article called 'Chips off the old Block', Gourmet Traveller Wine, April-May, 2006, Jancis Robinson laments the passing of terroir in budget wines.

"What is of concern, however, is the extent to which this globalisation of winemaking techniques will lead to a globalization of wine styles, at least at the bottom end of the wine market. Until now, there has been a distinct difference between basic European table wine on the one hand and the cheaper varietals of California, Australia and South Africa on the other-with the differences between these last three eroding over time. Will they all eventually end up tasting the same wherever they are grown on the globe?"

Most consumers are happy that wines taste better and if they begin to taste the same it would suggest that the effects of terroir were minimal or were being masked by the secondary affects listed above. Wines that may reflect terroir are the proverbial drop in a bucket in terms of the quantity made as all of the popular big brand styles will be blends from many regions.

There may be a test that can be devised to show that the taste of a wine really reflects its location. To get a better idea of the influence of the place many of the extraneous flavours that are added during the winemaking process would have to be removed. Then we would end up with a wine reflecting the pure fruit, possibly quite simple in its appeal and one that no connoisseur would like at all.