Wrestling with tannins

Regular readers of this blog will know that I have a strong interest in the language of wine. I find it fascinating that in the wine trade we frequently share our own private, conscious experiences of specific wines with others.

This, of course, requires that we develop a vocabulary for describing the taste and smell of wine (although I do know of a colleague whose tasting notes are embellished with a small graphic showing the ‘shape’ of the wine). It’s actually remarkably difficult to translate flavour perception into words in a way that is meaningful to others. Frequently, we achieve this by means of a code language, learnt through tasting with others in a structured manner. Part of wine education is, I suspect, learning this code.

In this codified language, the term ‘tannin’ crops up on a regular basis. Indeed, it’s probably the most common descriptor in tasting notes of red wines. Tannins can be soft, silky, smooth, harsh, green, velvety, coarse, rustic, fine-grained and even ‘filigree’. By using the term ‘tannin’, which is actually a chemical term, albeit an imprecisely defined one, tasters are making an assumption about the chemical entity that is causing this particular aspect of flavour perception.

However, I strongly suspect that most of the tasters using this term only have a vague understanding of what tannins are in a chemical sense. Do the many varieties of tannin described by tasters correspond with chemical realities? Or is this an example of a code in which the chemical term is merely borrowed?

One question that we should probably address is whether the link between perception and chemistry is important. Does it matter that tasters use chemical terms without these corresponding to what is occurring in the wine?

Parker and neuroscience

Thanks to fellow blogger Tyler Colman for bringing to my attention an interesting post by Jonah Lehrer on his blog The Frontal Cortex. He argues that the sensory limitations of the human brain make a nonsense of a serious belief in the 100 point scale.

He states:

The underlying assumption behind such point scores is that the taste of a wine is merely the sum of our inputs. But that's wrong: we can't quantify a wine by trying to listen to our tongue. This is because what we experience is not what we sense. Rather, experience is what happens when our senses are interpreted by our subjective brain, which brings to the moment its entire library of personal memories and idiosyncratic desires....Before you can taste the wine you have to judge it.

Two elements to wine criticism

What makes for a good palate?

There are two elements.

The first is the physical reliablity of a critic's palate. Can they spot duplicates in a line-up? How much do their ratings of the same wine, tasted on different occasions, differ?

Then it's the issue of aesthetic judgement. What is quality as it applies to wine? What makes one wine better than another?

Then, of course, there's the small matter of communicating this informaton in ways that are useful to readers.

If you have a poor palate, it doesn't matter how many wines you have tasted, or how many times you have tasted each wine, or how long you have deliberated over each wine for.

I don't mind whether someone tastes 20 000 wines a year or just 300 - what matters is their ability to taste accurately, make sense of what they are tasting, and then communicate this well.

And then there's the whole issue of biological differences in flavour perception, which add an extra layer to this discussion.

Rotundone: a chemical in wine responsible for pepper aromas

The Australian Wine Research Institute is responsible for some of the best wine research currently being done. One recent, newsworthy project has been the identification of a compound responsible for pepperiness in Australian Shiraz. Called rotundone, it is found in lots of herbs and vegetables, and it’s incredibly potent. For example, just 5 mls of rotundone would be enough to make all wine in Australia taste spicy. Finding it in wine is tricky, though, because of this potency: it’s like trying to identify one person out of six billion. Technically speaking, rotundone is a sesquiterpene.

The aim of this research? It’s to provide Australian winemakers or viticulturalists with the management techniques to be able to moderate spiciness in their wines. However, it’s also of interest that a proportion of people – as many as a fifth – simply can’t smell rotundone. This is one of the most fascinating of all the findings to me. The AWRI researchers state:

Whereas most of the sensory panelists were sensitive to rotundone, approximately
20% could not detect this compound, even in water, at the highest concentration tested (4000 ng/L). Thus, the sensory experience of two consumers enjoying the same glass of Shiraz wine or sharing the same meal seasoned with pepper might be very different. The variation in individual sensitivity to rotundone suggests that the way wines containing this compound are assessed by consumers or wine judges could vary substantially from one person to another. Similarly, the flavor perception of ground pepper might vary considerably among consumers. This is supported by the common practice of pepper being placed on the table or offered to individuals by restaurant waiters

You can access the original research papers here and here.

'People may be able to taste words'

Check out this recent BBC News Piece on synaesthesia (the jumbling of the senses). It features Charles Spence, a researcher from Oxford University, who is working with Heston Blumenthal on a very interesting-sounding project...

Music affects the perception of wine - a scientific study

An interesting study has been released today showing that music can affect the perception of wine.

Most of us have experience of wines showing differently according to context, but this study actually demonstrates that the style of the music can prime the listener and then alter their perception of a wine being tasted at the same time. The reason this is interesting is because information from one sense (hearing) is affecting another unrelated sense (flavour perception).

The study itself isn't a proper scientific paper, but rather a short publication of the results of a collaboration between Chilean producer Montes and Dr Adrian North, a psychologist working at Heriot Watt University in Edinburgh. 250 adults from the University were offered a glass of one of four Montes wines in exchange for answering a short set of questions about the experience of this wine. As they were tasting, one of four pieces of music were playing, or as a control, no music was played.

The four wines:

Montes Alpha Chardonnay 2006 - Majestic, Tesco & Morrisons £10.99
Montes Alpha Cabernet Sauvignon 2005 - Majestic, Tesco & Morrisons £10.99
Montes Alpha Merlot 2006 - Majedstic & Co-op £10.99
Montes Alpha Syrah 2006 - Waitrose & Tesco £10.99

The four pieces of music:

Powerful and heavy: Carmina Burana – Orff
Subtle and refined: Waltz of the Flowers (from The Nutcracker) – Tchaikovsky
Zingy and refreshing: Just Can’t Get Enough – Nouvelle Vague
Mellow and soft: Slow Breakdown – Michael Brook

The results showed a statistically significant shift in the perception of the wine with music type. The authors concluded that the study "...shows that the music shifted the perception of the wine in the direction of the mood expressed by the music by an average of 37.25%. The mean percentage for the white wine was 32.25% and the mean percentage for the red wine was 42.25%, meaning that the effect of music was stronger on the taste of red wine than on the taste of white wine"

You can read the report here.

NZ (3)

The time difference here is quite hard to get used to - it's actually 13 hours, which means that as I write this at 0815 on Friday, in the UK where I've recently called home it is 1915 on Thursday.
After a day sitting in a conference, last night we had a symposium dinner at the Vice Chancellor's Lodge, a rather grand residence overlooking the Otago Peninsula. The wines served were, once again, pretty good. I had Valli Pinot Noir 2006 from Bannockburn in Central Otago, which was very polished and quite elegant. I also tried a rich Dog Point Chardonnay, but didn't give it the attention it deserved.

Coincidentally, I had a good chat with one of the researchers who is working with a large population study here in Dunedin, and he has a PhD student working on PROP testing this group. PROP is a bitter tasting compound that some people can't taste, some people find mildly repellent and some people find utterly disgusting - there's a chapter dealing with this and the implications for wine tasting in my Wine Science book.

Anyway, with a bit of luck I should be able to find out my PROP taster status later today. The issue of individual differences in taste and smell perception is a really interesting one - it deserves more than just a blog post.

Also by way of coincidence, the previous evening, at a reception, I met a researcher who has been working with Dr Wendy Parr, a kiwi who has published extensively on sensory perception of wine. I need to go back and revisit her work.

Another day in the conference beckons today, and then tomorrow morning I'm off to Marlborough. I'm quite excited - it's always fun visiting a wine region you've heard a lot about, for the first time.