Monday, October 15, 2018

How aware are wine drinkers of wine regions?

A couple of decades ago, I used to order book from Barnes & Noble, in the USA, and have them sent to me, in Australia. I stopped doing this when twice in succession the books went to Austria, instead.1 B&N were charging me airmail rates but providing me with surface-rate service — Powell's bookstore, also in the USA, used to send me books by seamail, and they got to Australia faster, by not going via Europe.

The point here is that geography is not most people's strong suit, and they rarely consult a map — everyone "knows" that Australia is a small island somewhere off the coast of South America; and that Sweden (my current location) is somewhere in the Alps. It is only the locals who know where they really are.

So, how can we expect the average wine drinker to know where their wines come from? It turns out that we can't. Even awareness of the names of wine regions is very poor amongst the average wine drinker.

Wine Intelligence, a London-based organization that provides information support for the wine industry, conducts many surveys each year,2 and some of those surveys involve questions about wine regions. One of the 2018 surveys included a list of named wine regions, worldwide, and 4,000 "regular wine drinkers" in the USA were asked to specify which ones they could actually recall as being wine regions. The results are shown in the first table. [Note: the arrows refer to changes from previous surveys.]

You will note that there are 5 US wine-producing regions in the list, which all make it into the top 12 in terms of awareness. It is not surprising that Napa Valley heads the list, but you might like to ask yourself why 27% of the respondents have not heard of it, at least with regard to wine. Moreover, you could ask yourself why some of the foreign wine regions are better-known than the local ones. In particular, the winemakers of Oregon seem to have a lot of ground to make up.

Wine Intelligence survey of US wine drinkers

The French actually do better than the Americans, in the list, having 3 out of the top 5 regions, all with >50% awareness. The Italians do reasonably well, although you may be surprised that more people are aware of Sicily as a wine-producing region than they are aware of Chinati, Prosecco or Piedmont. We are repeatedly told by wine writers that Tuscany and Piedmont are the best-known Italian wine regions, but this survey says that they may have to revise their opinions.

No region outside of these three countries makes it into the top 20, or gets more than 20% awareness among the US wine drinkers.

Almost this same survey was also given to 2,000 well-to-do Chinese people who self-reported as being drinkers of imported wines. Their results are shown in the next table. Note that the general awareness of the names of wine regions is less than it is for the US drinkers (possibly due to the language barrier).

Wine Intelligence survey of Chinese wine drinkers

Bordeaux is the only region that achieved >50% awareness, even though French wine massively dominates the Chinese wine-import market. Moreover, Bordeaux handsomely beats the only Chinese region in the list. Other countries do better in this survey than in the American version — for example, the Australian regions have greater awareness, which is not unexpected given that Australian wine is second only to the French in China.

For me, the most interesting result is, once again, the position of Sicily in the list, which has considerably greater awareness than all of the other Italian wine-making regions. It is only a dozen years or so since Sicily returned to the "wine map" of Italy, as drinkers and critics alike started to realize the vinous potential of the island, but it has clearly come a long way in that time.

Australian wine regions

Wine Australia, the nationally funded statutory service body for the Australian grape and wine community, has been interested in the awareness of Australian wine regions, outside of Australia. To this end, they commissioned Wine Intelligence to conduct a bespoke survey in July 2018, in both the USA (1,000 people) and China (2,000 people). The survey had two parts: (i) a list of 15 Australian wine-growing regions, used as a prompt for awareness; and (ii) a request to list Australian wine regions without any prompting.

Wine Intelligence survey of US and Chinese drinkers

The results are discussed in this report: What’s in a name? A look into awareness of Australia’s wine producing regions. I have summarized the data for the prompted list for both countries in the above graph, which shows the percentage awareness. [Note: the tables shown above are reproduced directly from this same report.]

Note that the recall of the names of Australian wine regions is much greater among the Chinese than among the Americans — indeed, the greatest US recall is equal to the lowest Chinese recall. Furthermore, the four regions labeled in the graph indicate that the Americans and Chinese recall very different wine-making regions from Australia.

The final table (below) shows the responses from the US drinkers when asked to name some Australian wine-producing regions without any prompting. The table lists the top 15 responses, listed from top to bottom in terms of frequency; and they are grouped into columns based on what the names actually represent.

Wine Intelligence survey of US drinkers

The most popular response (from only 6% of the respondents) was the name "Yellow Tail", which of course is the name of the most popular imported wine brand in the USA (see this blog post). The wine-producing region for this brand is actually called South-Eastern Australia, since the grapes come from several irrigated grape-growing areas.

So, only 4 of the 15 responses listed in the table are actually the names of wine-making regions in Australia; and 3 of the others are not even geographical terms, but merely words from wine labels.

This reminds me of another recent report I read, which showed that UK drinkers do no better — when asked about the most famous Australian wine region, the answer by the majority was apparently "Jacob's Creek", which has been the most popular Australian wine brand in the UK.

I will have to redress this general lack of awareness of Australian wine geography in a future blog post!

1. The name "Austria" comes from the Medieval Latin word "Austriaca", which is the Latinised form of the Old High German name for the country "Ostarreich", which translates as 'eastern kingdom'. The name "Australia" comes from the Latin word "Australis", translating as 'southern', as used in e.g. the expression "Terra Australis", the southern land.

2. The survey methodology is described as:
"Invitations to participate in an online survey programmed by Wine Intelligence are distributed to residents in each market. Respondents are directed to a URL address, which provides access to the online survey. Based on given criteria (e.g. age, beverage, frequency of wine consumption) respondents will either proceed or be screened out of the survey. [We] monitor completed responses to build samples representative of the target markets’ wine drinking population based on the most recent calibration study. When a representative sample is logged, the survey is closed. Wine Intelligence will then clean out all invalid data points (e.g. those who sped through the survey or gave inconsistent answers to selected questions) and weight the data in order to ensure representability."

Monday, October 8, 2018

The number of wineries per US state

A few weeks ago I wrote about The number of wineries in the USA, looking at the changing number through time. However, I did not look specifically at the current numbers of wineries in each of the states, which is what I will do here.

The data shown here come from the U.S. Tax and Trade Bureau (Bonded wine producers count by state: 1999–2018), and are current as at 30 June 2018. Note that: "Bonded winery premises include every licensed production facility of single firms or individuals, licensed warehouses, experimental wineries and wineries with no casegoods production or fermentation capacity." It is also important to note that the number of winery premises per state is not necessarily related to either wine production or vineyard area.

The number of wineries in each of the US states

Note that the vertical axis in the graph, which counts the number of wineries, uses a logarithmic scale, while the states are simply listed horizontally in decreasing order of winery numbers. As expected, California is way out in front (with 4,481), followed by Washington (1,089) and then Oregon (713). Interestingly, Texas (602 wineries) is then just ahead of New York (593), indicating that not all "winery premises" are necessarily associated with either vineyards or large wine production.

One thing that I have emphasized in this blog is that so many potentially complex patterns can often be modeled with incredibly simple mathematics. In particular, patterns are often very well fitted by what are known as Power or Exponential models, which are among the simplest available. This is what makes mathematicians fascinated by the world, and leads to their long-held belief that the creator of the universe was obviously a mathematician. (Biologists, such as myself, think instead that the creator had "an inordinate fondness for beetles".)

It is, however, important to remember that we are interested in both the way in which the data fits the model and the (possibly many) ways in which it does not fit. Both aspects tell us something, although often very different things — the proverbial glass is both half full and half empty, and we would do well to be interested in both halves.

In this case, the next graph shows you that the winery count data fit an exponential model (drawn as the line) very well (97% fit), with two exceptions. Both California and Washington do not fit the model (highlighted in pink), although most of the other states do fit very well.

An exponential model fitted to the number of wineries in each of the US states

In this case, the excellent fit to the model is intriguing. There are obviously many factors that could possibly influence the number of wineries that exist in any given state of the USA, and yet these all seem to "cancel each other out", leaving us with a very simple pattern. The commonness of such patterns tells us that we should not be surprised by this — it is simply the way the world works, so that complexity leads to simplicity.

On the other hand, California and Washington stand out clearly — they both have many more winery premises than the model indicates can be expected for the top two states. This is presumably a by-product of history. For example, not only has California been the leading wine producer since the Spanish missionaries first started making wine there, but it weathered Prohibition better than any other state, and was thus in a position to take advantage of the post-World War II boom in wine appreciation. "Go west, young man" has a special meaning for viticulturists, as well as movie makers!

Monday, October 1, 2018

Grape clones and varieties are not always what they seem

The twin ideas of "varieties" and "clones" are basic to grape-growing, whether they are used for wine-making, table grapes, raisins, juice, jelly, canning, or rootstocks. However, these concepts don't quite match the usage of these words in general biology. In practice in grape-growing, a variety is a variety when it is officially declared to be such, and the same for a clone, not when they match the biological definitions.

Illustration By Keith Ward

Jamie Goode (What is a grape variety? What is a clone?) notes that, in biology, a new variety is produced by sexual reproduction, where there is cross pollination between a mother and a father flower from different varieties, resulting in a seed, which is then grown as a new plant. That new plant could then be a new variety. Clones, on the other hand, come from vegetative propagation — a genetic mutation occurs in a plant's growing tip, which then forms a new shoot, and then a cutting of that shoot is taken and propagated, to form a new plant. That new plant could be a new clone.

Obviously, new varieties and new clones are normally recognized in the grape-growing industry only if they have desirable characteristics that are not present among the current collection of varieties and clones. If not, then the new plant will be discarded. So, not all mother x father crosses will produce new varieties, nor will all cloned plant material be recognized as a new clone.

The point here is that varieties will have considerably different genetic makeup from their parents, since they have genomes that are a mixture of those from both parents. Clones will, instead, be almost identical to their parents, likely differing only in a single mutation in their genome. This is what creates the difference between the word "variety" as used in grape-growing and its more general usage in biology — grape varieties are sometimes almost identical!

The Pinot group of "varieties"

You see, by these formal definitions of variety and clone, grapes like Pinot noir, Pinot gris and Pinot blanc would not be separate varieties, but would instead be separate clones — they were originally produced by the process of vegetative propagation, and are genetically almost identical. Pinot noir is a very ancient variety within which many mutations have occurred naturally over the centuries, some of which we have recognized as worthwhile, by viticulturists taking cuttings and producing new plants — hence, the "family" of Pinots.

The table shown later in this post shows you what I mean. However, most people don't know how modern viticulture uses genetics to recognize different grape clones and varieties, so I will first explain the genetics here.

Each individual organism has its own unique genome, even identical twins (after their first cell division). However, there is an awful lot of each genome that is identical across groups of organisms, whether those groups are entire kingdoms, such as animals or plants, or much smaller groups, such as grape varieties. This allows us to use the genome to identify which group each individual belongs to. All we need to do is find some bits the genome that vary between the groups but not within those groups.

Microsatellites are bits of the genome that are useful for identifying closely related organisms, such as varieties. Each microsatellite is a location in the genome that is known to be very variable, because part of the genome sequence at each location is repeated many times. This is illustrated above, which shows three genomes (horizontally) — the first genome has 5 repeats (represented by the blue arrows), while the second one has 7, and the third one has 3 repeats.

Just as importantly, each microsatellite needs to have an immediately adjacent region of the genome (marked in red in the figure) that does not vary within or between groups. We use these flanking regions to find the microsatellite within the genome, and to count the number of repeats between the paired flanks.

Note that there are two copies of the genome for each individual in the figure, just as we ourselves have — one from our mother and one from our father. The blue arrows point in opposite directions for the two copies, because the copies actually function in opposite directions.

There are oodles of microsatellites in the genomes of all complex organisms, but for grapes we have chosen just nine of them, which we have given the fancy code names listed at the head of each column in the table below. To identify any given grapevine genetically, we simply count the number of repeats it has at each of the microsatellite locations, and we then compare this to what we already know about different grape varieties. When we find a match — bingo, we have identified its variety, which is why this procedure is sometimes called DNA-fingerprinting.

Microsatellite counts for different Pinot grape varieties

For the Pinot example in the table, I provide the relevant genetic information for six different grape varieties (taken from Liste des clones agréés en France). The columns of the table refer to the nine microsatellites, and the data within the columns tell you how many repeats there are for each microsatellite (typically several hundred repeats).

The rows refer to the six grape varieties. Different varieties usually have uniquely different numbers of repeats for these nine microsatellites. There are two "alleles" for each variety, because the grapes have two copies of their genome — the allele pairs do not have to have the same number of microsatellite repeats.

Looking through the table above, you can see that Pinot noir, Pinot gris and Pinot blanc have 18 identical numbers, meaning that they are genetically identical for both alleles at all nine locations in their genomes. This is what you can expect to see most of the time when comparing clones — clones are expected to be identical. As also shown in the table, Pinot meunier, another Pinot clone, differs in only 2/18 numbers.

For comparison, Gamay noir differs from Pinot noir at 10/18 microsatellites, while Chardonnay differs at 7/18, indicating that in both cases they were originally produced by cross-pollination, not cloning — they vary too much to be clones. This information also suggests that Chardonnay is more closely related to the Pinots than is Gamay (the microsatellites are not involved in determining skin color, and so the color mutations are not involved in the identification process). Both Chardonnay and Gamay are currently estimated to be the result of crosses of Pinot noir with the Gouais blanc variety, which is no longer even listed for viticulture in France. The Gamay cross is likely to have occurred much earlier in history (and there are lots of other varieties that are also the offspring of Pinot x Gouais crosses).


Grape varieties are whatever the grape industry decides to recognize. Mostly, they match the definition generally used in biology — new varieties result from sexual reproduction, while new clones come from vegetative propagation. However, modern genetics has allowed us to recognize that this is not always so — some clones are too important to the industry not to have their own varietal name.

Finally, it is perhaps worth noting that not all new varieties are universally revered. Sometimes, they are more "interesting", rather than simply an improvement (eg. An ancient, rare wine that can be beautiful, or smell like old lady's perfume: Lacrima di Morro d'Alba ).

Monday, September 24, 2018

Musings on grenache

I have always thought that one of the most intriguing grapes is the one usually known as Grenache. This is because you can make such a wide variety of styles and make them all well — everything from strong and tannic (eg. in Priorat), through herbal and spicy (eg. southern Rhône), to soft and fruity (eg. Barossa), and on to rosé (eg. Tavel and Provence), as well as dessert wines (eg. Banyuls). To me, very few of the usual rosé grapes can make a fine red wine, and few of the red-wine grapes can make a good rosé — it is "horses for courses", except for Grenache.

This musing was inspired by reading two wine articles in the same week, one extolling the virtues of Grenache in California (How California’s Central Coast winemakers are making grenache their own) and one extolling the virtues of Grenache in South Australia (Great groovy grenaches). These articles embody two different approaches to the topic of making wine from Grenache, but they both focus on making mono-varietal wines. of which we are seeing more and more these days.

Traditionally, in southern France Grenache is combined with Shiraz / Syrah, and sometimes also Mourvèdre / Mataro, or even Carignan, while in Rioja it is blended with Tempranillo. All of these blends are excellent uses of Grenache, but it can easily stand on its own if handled correctly. Mind you, Grenache can also make some pretty uninspiring wines, if you don't pay attention to what you are doing, especially regarding over-cropping.

To quote the Australian article: "Lighter-bodied, lower-tannin, soft, fruity, early-drinking red wine is in vogue everywhere, and is being promoted by a younger generation of winemakers who need to sell their wines young. In places ... where they can’t do much of consequence with Pinot Noir, astutely produced Grenache can perform a similar role."

To quote the US article: "Vintners ... are shedding that [jug wine] baggage. They’ve optimized viticulture and dialed back the tonnage to produce varietal Grenache as nuanced and delicious as top-shelf Pinot Noir — often at half the price. Winemakers explore both the rich, ripe side of the grape, which retains acidity deep into the harvest season, as well as lighter, fresher expressions that play up floral aromatics and taut textures."

Formally, the grape's name is Grenache Noir, to distinguish it from the white-wine Grenaches (Grenache Blanc and Grenache Gris). However, since the variety most likely originated in the region of Aragon in northern Spain, we should probably use its Spanish name: Garnacha Tinta. It has even been suggested that the Aragonese (who use the Catalan name: Garnatxa Negra) originally got the grape from Sardinia, where it is called Cannonau. However, it was apparently first recorded in Spain in 1479, in Sardinia in 1549, and in France in 1780.

The grape ripens late, and so it is widely grown in areas that are too warm for, say, Pinot Noir, with which it is so often compared. The above map is taken from: Distribution of the world's grapevine varieties (produced by the International Organisation of Vine and Wine, 2017).

Winemakers worldwide often comment on the "malleability" of Grenache, as well as on its ability to express terroir. It is less distinctive as a grape than are many other varieties and so, as noted above, it can make a wide variety of styles. It is thus somewhat surprising that Pl@ntGrape lists only 23 approved clones in France, compared to 20 for Cabernet Sauvignon but 47 for Pinot Noir.

There are a number of examples where Grenache has been used to make interesting vinous comparisons. For example, in Australia The Artisans of Barossa Grenache Project involved six winemakers each taking a row of Grenache from the same Barossa Valley vineyard in 2017, and then applying their own vinification and maturation approaches, thus producing six different wines. These wines were released as a 6-pack, thus allowing wine lovers to make the direct comparison of wine-making versus terroir. In that regard, Max Allen noted: "10 months after vintage, the winemaking influence is far more obvious than the vineyard-derived characters that all six wines should, theoretically, share."

With a somewhat different objective, in Spain Celler de Capçanes produces a 4-pack of wines called La Nit de les Garnatxes (this is Catalan; in English, it would be: The Night of the Grenaches). These are Grenache wines produced from grapes grown on each of the four different soil types in their Priorat vineyards: limestone, clay, slate / schist, and sand / alluvial. In this case, the same wine-making technique is applied, so that wine lovers can make a direct comparison of the four terroirs.

Finally, it is worth noting that there was a Global Garnacha Summit earlier this year, held in Napa but hosted by the producers from the Spanish wine region of Cariñena. The main topic of discussion was the resurgence of Grenache wines, and there are several summary reports to peruse (eg. here and here). Furthermore, there is actually an International Grenache Day, which is the 3rd Friday in September — this year that was last Friday. To celebrate, the organizers suggest: "Just open a bottle of Grenache wine, or blend, and share it with friends, family, business contacts." My wife and I had a bottle of this:

Fire Block Old Vine Grenache 2012

Monday, September 17, 2018

The number of wineries in the USA

We all know that the number of wineries in the USA keeps increasing, but few people know just how many there are, or how rapidly the number is increasing. Well, this is precisely the sort of thing that the government likes to keep a track of, and they do not hide the information from us.

The data in the following graph come partly from the U.S. Tax and Trade Bureau (Bonded wine producers count by state: 1999–2018) and partly from the Wine Institute (Bonded wineries — data prior to 1999). To make this clear: "Bonded winery premises include every licensed production facility of single firms or individuals, licensed warehouses, experimental wineries and wineries with no casegoods production or fermentation capacity." That is, pretty much everything.

Number of US wineries through time

So, that makes 12,573 facilities as of June 30 2018. This is one winery for every 30,000 persons in the country.

There was a decline in number from World War II until 1965, presumably also still reflecting both Prohibition and the Great Depression. However, from 1970 there has been an exponential increase in the number of wine facilities, as shown in the next graph.

Fit to the exponential model of the number of US wineries through time

The exponential model fits very well, which means that the rate of increase is itself increasing each year. Indeed, the number of wineries is multiplied every year by c.1.07 (on average, each year there is an increase of 7% over the previous year). It is not obvious how long this rate of growth can be maintained, since there is a finite amount of land area on which to construct these facilities. However, it has been going on for a half-century now, with no sign of abating.

Obviously, not every year has exactly the same increase, as shown in the next graph, which simply shows the annual change in number.

Annual change in the number of US wineries

First, note the apparent boom between 1975 and 1980. This is an artifact — it is the accumulated number of new facilities over 5 years (341), not just 1 year (presumably, c.70 per year). Second, the apparent boom in 2011 also looks like a possible artifact — the preceding decline, plus the boom, looks like there were a whole lot of new facilities that were not recorded during 2008-2010, which were then included in the 2011 census. However, this same pattern is repeated across all of the states, as shown (in green) for California in the next graph. So, whatever it was that caused this was widespread.

Annual change in the number of California wineries

Speaking of California, it is appropriate to finish with a consideration of how the biggest wine-producing state fits into the national pattern. This is illustrated in the final graph, which shows the number of California facilities as a percentage of the national total.

Percentage of US wineries that are in California

Note that the increasing dominance of the California industry until 1965 (reaching 57%) coincides with the general decline in the national number of wineries. This maximum percentage was maintained until 1984, after which there was a rapid rise in winery numbers elsewhere — that is, until 1986, the number of new facilities outside California grew more rapidly than the number inside. Things steadied after that, with the increase in numbers both inside and outside California keeping pace with each other until the end of the century.

However, the last time California had more than 50% of the US wineries was in 2001; and its dominance has steadily decreased since then. Nowadays, people are simply setting up more facilities outside California than inside it — after all, there is a lot more potential vineyard land outside. Presumably, this trend will continue for the foreseeable future.

Monday, September 10, 2018

Keeping the family wine business is often hard

Fred Swan has recently noted that: “The vineyard and winery business in Napa Valley has, over the past 50-some years, largely shifted from small, family-owned wineries, to multi-brand corporate ownership, and then to proprietorships of uber-wealthy people who needn’t worry about shareholder dividends.” Some other parts of the world have followed the same path, notably Bordeaux and Burgundy, although most places stop at corporate ownership.

Nevertheless, throughout much of the world, vineyards and their associated wineries are often family-run concerns, either small or large (for the very large, see The curious dominance of family-owned wine businesses in the U.S.).

Indeed, it is often treated as commercially desirable that a wine business should be seen as family run, even after it has been bought by a large corporation. In this regard, Australia's Robert Hill Smith (who heads a family-owned wine business) has said: “I’m really sick of the latest trend for corporate misuse of the term ‘family’ when promoting wine brands that were sold by the family founders eons ago, and conning wine-loving consumers and trade alike.” Indeed, in Australia, you can consult a list of companies who do precisely this: Who makes my wine?

As far as families are concerned, Rebecca Gibb has noted that: “four in five family wineries in the US [are] still in the hand of first-generation owners.” One reason for this is that keeping the business in family hands is one of the hardest things to do, whether it is the wine business or not: “According to the Family Business Institute, 75 percent of businesses don’t transition to the second generation, and only one percent survive past the third.” For wineries, Fred Swan points out that: “For many long-term, family winery owners, the only way to fund retirement for themselves and their employees, divide assets among children, or fund improvement or expansion is to sell.” Indeed, Richard Mendelson is quoted as noting: “Winery sellers can be owners who need capital to expand but lack it, or lack the front or back office staff needed to expand. Sometimes, they are families whose 'next gen' are uninterested in staying on or can’t agree on how to run the business.” See also Brian Freedman's article on the topic.

This raises the interesting question of just how many vineyards / wineries have made it through several generations, and still remain in family hands today. For example, Italy’s Marchesi Antinori wine company is still family owned after 26 generations (as noted on their logo, shown above). This is in sharp contrast to, say, the Mondavi family's well-reported succession problems, which even became the subject of a book (The House of Mondavi: the Rise and Fall of an American Wine Dynasty. Julia Flynn Siler, 2007).

Some data

I would not even dream of tackling this question with reference to anywhere in Europe or North America, because the data-collecting would defeat me. So, I will adopt my tried-and-true approach of using Australia as my example — Australia has 25 million people to search among, not 350 million!

So, here is a list of current Australian wine companies that were founded all the way back in the 1800s, and which have maintained the same basic name, even if their associated vineyards have not been continuously maintained.1 It is based on: Australia’s oldest wine companies or continuously operating brands.

Wyndham Estate
Olive Farm Wines
Yering Station Vineyard
Sandalford Wines
Oliver’s Taranga Vineyards
Penfold’s Magill Estate Winery
Pewsey Vale Vineyard
Orlando Wines
Bleasdale Wines
Seppeltsfield Winery
Sevenhill Cellars
Drayton’s Family Wines
Normans Wines
Mudgee Wines
Chambers Rosewood Winery
Gehrig Estate Wines
St Leonards Vineyard
Tyrrell’s Vineyards
Morris Wines
Saltram Wine Estates
Jones Winery & Vineyard
Mount Prior Vineyard
Tahbilk Wines
Hardys Tintara Winery
St Huberts
Goona Warra Vineyard
All Saints Estate
Turkey Flat Vineyards
Best's Great Western
Campbells Winery
Stanton [& Killeen] Wines
McWilliam's Hanwood Estate
Brown Brothers Milawa Vineyard
Angove Family Winemakers
Kay Brothers Amery Vineyard
Pirramimma Wines
Year established
1849  AFFW
1858  AFFW
1860  AFFW
1868  AFFW
1870  AFFW
1877  AFFW
1885  AFFW

The table lists all still-extant companies that were founded up to 1864. There were plenty of other companies founded during that time, but they no longer exist under their original name. For example, these companies have also operated continuously since their founding: Hope Estate (founded 1850) became Seaview (in 1950), before being absorbed into Treasury Wine Estates; Craigmoor (1859) is now Robert Oatley Vineyards; and Quelltaler Estate (1863) is now the corporate-owned Annie's Lane.

In the table, I have highlighted in boldface those companies that are are still in the original family's hands today (8 out of 32). To them, I have added the other continuously family-owned companies that I know of that were founded before 1900 (another 10). Note that some of the other companies listed in the table are currently in family hands, just not the hands of the founding family.2

That's not a bad list, really, since it adds up to 18 Australian wine companies with continuous family ownership for more than a century.


There have been a number of organizations gathering together families who have made it through several generations of winery ownership. For example, in Europe there is Primum Familiae Vini (founded 1993; currently 11 member companies); in New Zealand there is the Family of Twelve (founded 2009); and Australia has Australia's First Families of Wine (founded 2009; currently 12 members).

Obviously, it is the latter group (abbreviated AFFW) that is of relevance to the discussion here; and seven of the 12 member companies are highlighted in the table above. The group name is a bit cheeky, as it cannot refer to the "first families in time", given the number of other long-term ownerships listed above. The five AFFW companies missing from the table were sometimes founded much more recently:

De Bortoli Family Winemakers
Jim Barry Wines
Taylors' Wines
Howard Park (Burch Family Wines)
Year established
1912  AFFW
1928  AFFW
1959  AFFW
1969  AFFW
1986  AFFW

Nor can the group's name actually refer to "first in quality", in spite of the fact that their stated primary aim is to promote high-quality Australian wines:
The underlying rationale for the formation of Australia's First Families of Wine was the realization that export markets had either lost sight of or had no way of knowing about Australia's rich history, it's diverse regions and wine styles, and the fierce personal commitment of the best winemakers to the production of high-quality wines true to their variety and geographical origin.
The criteria for membership are relatively straightforward, including: being family controlled (in a legal sense); having a history of at least two (preferably three) generations involved in the business; the ability to offer a tasting of at least 20 vintages of one or more iconic brands; ownership of established vineyards more than 50 years old and/or distinguished sites that exemplify the best of terroir; a commitment to environmental best practice in vineyards, wineries and packaging; and long-term commitment to export markets.

However, there are other family-owned wineries who meet these criteria, and yet who are not members. Grant Burge Wines (founded 1988) is an obvious example, with its Meshach Shiraz (first vintage 1988), with grapes sourced from the Filsell Vineyard (established in the 1920s). However, many, if not most, of Australia's iconic wineries do not have vineyards that are 50 years old (yet).

However, the sticking point for membership seems to be the criterion that I did not list above: family member service on wine industry bodies. This is an impossible ask for most family-run businesses, because most of them are relatively small — the time commitment is often simply not there, even if there is a family member willing (or able) to take on the task. Most family-owned Australian wineries are thereby excluded from the AFFW, because they are not large enough.

Finally, it is ironic that their bid for international recognition of the quality of Australian wines pits the AFFW squarely against Australia's largest family-owned wine company: Casella Wines (founded 1969). It is the great success of Casella's Yellow Tail (the best-selling imported wine brand in the USA) that has given Australian wines their 21st century reputation as easy-drinking and innocuous. So, it is a group of 12 families against a single family (plus all of the large corporations).

Mind you, all of this it still leaves us with a moot question: Should you join the family business?

1 Some of the names have changed a bit over the years. For example, just the other day Brown Brothers changed its name to Brown Family Wine Group.
2 I should note that the founding date for Best's is stretching the definition a bit. The company was in the Best family's hands until 1920, when it was bought by a neighboring family, the Thomsons, who had founded their own winery in 1893 — they have owned Best's ever since. Tulloch (founded 1895) is another tricky case, the company having been re-purchased by the Tulloch family in 2001.

Monday, September 3, 2018

The poor mathematics of wine-quality scores

Language is all about communication. If you say something and I don't understand it, then we are both wasting our time.1 For example, a Swede and I were looking at a book the other day, in which one of the female characters referred to another one as "duck". My colleague interpreted this as insulting, because it would be so if you did the same thing  in Swedish (using the word "anka"). However, it seemed to me that "duck" and "ducky" were precisely the sorts of expressions that buxom barmaids used to use in those 1960s British television shows that I saw as a child, in which it was a friendly term. It turned out that the book was set in London, and published in 1958, so that was the correct interpretation.

Celia Fremlin — The Hours Before Dawn

This sort of variation in interpretation is one reason why word descriptions of wines are frequently disparaged, because it is often rather difficult to work out what all of this flowery language is supposed to mean (see my post on Wine writing, and wine books). In turn, this dissatisfaction is one reason why wine-quality scores are popular, because mathematics is supposed to make communication pedantically precise.

For example, in the early 1900s Jacques Futrelle created the character Professor van Dusen (also known as The Thinking Machine), who solved mysteries by the remorseless application of logic. His mantras was: "Two and two equal four, not just some of the time but all of the time".2 This emphasizes the ultimate goal of mathematics as a language, that we cannot go wrong — a mathematical proof of a proposition is as close as we can get to certainty.

However, to use of this advantage we must be rigorous, and be pedantic about our intention, as well. This is often problematic, because most people manage to forget all of the mathematics they were taught at school, within minutes of leaving that school for the last time.3 For example, you should all recognize that van Dusen is actually wrong, because the assumption that the sum uses base10 is not warranted, and in base2: 1 + 1 = 10.4

So, wine-quality scores will only be at their best as a means of communication if they follow the logic of mathematics. Sadly, they rarely do.

Augustus S.F.X. van Dusen

Best-case scenario

The first widely applied wine-scoring system was the 20-point scale developed in the 1950s by Maynard Amerine and his colleagues at the University of California, Davis. In this scheme, each organoleptic characteristic of the wine is assigned a number of points based on its perceived quality, and these points are summed to produce the final score. The wine characteristics include: appearance, color, aroma and bouquet, total acidity, sweetness, body, flavor, bitterness, and astringency,

In theory, everyone who uses the UCDavis scale should be "speaking the same language"; and therefore any differences in wine scores should represent differences in perceived wine quality, not differences in the use of language. However, in practice, this will be true only if summing the sub-scores makes mathematical sense — if this is not so, then the sum is not a repeatable mathematical quantity.

For the sum to make any mathematical sense, each possible quality point has to mean exactly the same thing as every other possible quality point. That is, a point for color has to mean exactly the same thing as a point for astringency; if not, then adding the points has no precise mathematical meaning. Furthermore, every user has to mean exactly the same thing when they assign each quality point. It is like counting apples — we all need to agree on what an apple is, and then we need to be able to recognize each apple when we see one; if I try to add 3 apples and 3 blackberries, the sum of 6 may not make much sense.

Is this required uniformity of the points likely to be true in the case of wine-quality assessment? I doubt it, although I would love to have someone demonstrate that I am wrong. This means that, even in this situation, where the input to the quality score is pre-specified as the sum of a set of parts, the mathematics is not helping us communicate as much as we would like. And this is the best-case scenario!

Maynard Amerine (left) and Edward Roessler (right)

Usual scenario

On the other hand, most wine commentators do not use any such scoring scheme. Their wine-quality scores are personal to themselves. That is, the best we can expect from each commentator is that their wine scores can be compared among themselves, so that we can work out which wines they liked and which ones they didn't. However, the scores cannot be compared between commentators at all.

I have shown this unfortunate situation in two main blog posts, where I directly compared the scoring systems of several professional commentators for the same wines:
No-one's scores were the same as anyone else's, irrespective of what set of points they used. So, differences between scores could mean differences in wine quality, but they could just as easily reflect differences in the interpretation of the numbers. In this case, the numbers are no better than are words as a means of communication. It is like watching someone from Scotland trying to talk with someone from Texas — they may ostensibly be using the same language (English), but they may also find that their communication is an uphill battle.

Jancis Robinson, when she was a bit closer to her maths days


Obviously, we shouldn't conclude from this that points are pointless. But we might conclude that the sometimes-heard argument that numbers are more precise than words does not really apply in the case of wine-quality assessments. Even in the best-case scenario, where sets of points are added together to produce the score, might make little mathematical sense.

I believe that this is the main reason why the best-known mathematically trained wine commentator has repeatedly said that she is wary of assigning quality points to the wines that she tastes. This is Jancis Robinson, who has a degree in mathematics (and philosophy) from the University of Oxford. As far as I know, she has never put it this way, but she could do so with perfect assurance: wine assessment is no better using numbers than words, because the numbers violate many of the mathematical requirements for a precise language.


Tom Wark has posted a very intersting response to my comments over at his Fermentation blog: A wine rating is an adjective, not a calculation. In one sense he does not disagree with my conclusion, but instead disputes the premise that numbers must be treated as calculations. My reply (as posted on his blog), is to question "why, given that the numbers are not mathematics, we are using mathematical language in our attempt to communicate. To me, this is like using English words without creating English sentences! So, if a wine rating is an adjective, then don’t use a number, because this is a very poor substitute for an adjective."

1 Unless I happen to like the sound of your voice! I have long thought that one reason the English have traditionally disliked the French and the Scots is that, for spoken English, both groups have accents that are much more melodious than any of the numerous English ones.

2 This idea goes back a long way. For example, in Johann Wigand's De Neutralibus et Mediis Libellus (1562) we find: "That twice two are four, a man may not lawfully make a doubt of it, because that manner of knowledge is grauen [graven] into mannes [man's] nature."

3 See Why do Americans stink at math?

4 We expect numbers to be in base10 because we have 10 fingers, but any base is actually possible, and to be pedantic we should always specify which one we are using. Computers, for example are binary, and thus use base2, while computer programming often uses octal, which is base8, or hexadecimal, which is base16. Given the number of devices in the modern world that have a computer processor in them, base2 is almost as common as base10 these days.

Monday, August 27, 2018

Estimates of cork taint from the Wine Spectator Napa office

The Wine Spectator magazine's Napa office tracked the number of apparently cork-tainted bottles in their tastings of California wines from 2005 to 2016, reporting their results at the beginning of the next year. There has been no report on the situation in 2017; and James Laube, who wrote the reports, has recently retired from regularly doing the California tastings (Wine Spectator announces changes in California wine reviewers). So, this could be an appropriate time to review their data.

A corked wine

Each year, all of the bottles tasted in the Napa office were assessed for "off" aromas. For bottles with corks, taint is usually caused by the presence of the chemical trichloroanisole (TCA) in the cork, but there are other potential sources of off smells. For example, the Cork Quality Council also lists 1-octen-3-ol, 1-octen-3-one, and guiacol.

Whatever the source, the data in the following graph refers to the "off" wines as a percentage only of those bottles with corks. Obviously, the data show that the percentage of tainted wines has improved through time.

Cork-tainted bottles in the Wine Spectator tastings of  California wines

Indeed, the trend looks impressively like cork quality is steadily improving. However, as I mentioned in a previous post (Drawing lines through a graph of points — what does this mean?), fitting a trend line to a graph can be a deceptive business. For example, the dashed pink lines in this next version of the graph highlight a different pattern — that tainted wines decreased between 2009 and 2010, but have otherwise remained relatively steady before and after then. Maybe something happened at that time?

Cork-tainted bottles in the Wine Spectator tastings of  California wines

Either way, the cork industry is usually reported to have a much lower estimate of cork failure than is shown in the graph above, typically 1-2 percent. This estimate was clearly not believable 10 years ago, and it is still half of that reported by the Wine Spectator, even now.

The cork manufacturers (mainly in Portugal) have been reported to be getting their act together, to improve the situation (eg. Taint misbehavin’: improving TCA testing methods to ensure cork quality). Improved testing may explain the apparent improvement between 2009 and 2010. The basic issue seems to be getting the cork wood clean, so that it can be turned into wine stoppers. Indeed, the industry is claiming that they will have eradicated TCA by the year 2020.

This raises the point as to why we use corks for wine bottles in the first place. Vidon Vineyard has this to say on the matter:
The main reason corks remain the predominant closure is tradition; change doesn’t come about easily in many fields. As long as one is willing to accept an occasional bad bottle of wine, corks are fine.
In any case, it seems clear that consumers often associate corks with high-quality wines (The effects of wine bottle closure type on perceived wine quality).

Vidon Vineyard's comments raise another important point:
A problem is that much of the time a cork-tainted wine isn’t recognized as such, but is passed off as “just not a good wine”, which means it’s the winemaker’s fault. And oftentimes a slightly tainted wine is consumed as “not too bad”, while if it could be tasted alongside an untainted wine with the same label, the reaction may have been “wow, this is great”!
Given that most wines are drunk within a few months of being released, the idea that we need corks in these particular wines seems to be ludicrous. Apart from anything else, untwisting a screw cap is so much easier!

On the other hand, we might also be concerned about the fate of the Cork Oaks (Quercus suber) themselves. These trees are owned and managed by farmers, who need to make a living from their land. If they can no longer make money from their cork trees, then those trees will be under threat of being replaced by some other crop. According to the Cork Quality Council, 37% of the cork forests are in Portugal (and 27% in Spain), where 50% of the cork production is centered (with 31% in Spain) — so, this is where the effect will be felt. In 2015, wine corks represented 72% of the Portugese cork industry's value, worth €644 million. This is not an inconsiderable industry, which will exert pressure to keep the Oaks.

Monday, August 20, 2018

How long should we cellar our wines?

A few weeks ago I raised the issue of how long we should keep our newly purchased wines, in order to drink them while at their best. Most of us have no idea about how to decide this, so we might seek advice from people who possibly know more than we do. However, it is usually rather hard to do this, unless the actual winemaker has suggested something.

From Wine Folly

This because most wine writers seem to either: make rather generic statements (eg. based on the origin of the wine), or be very vague (eg. short-, medium-, long-term cellaring), or ignore the topic entirely. I don't blame them. There are two parts to the problem of making such a decision: (i) where are the wines being stored? and (ii) why are you storing them? Recently, Tom Maresca recently wrote a blog post addressing both issues with respect to his own cellar (Tales from the crypt: a cellar story):
Most collectors would scream with horror at such an uncontrolled repository for their wines, but I’m not a collector and never have been ... The wines I’ve stored over the years have been a hodge-podge ... So if less-than-perfect storage conditions meant speeding up their maturation — in effect adding a few years to their calendrical age — that was and is no problem for me. In fact, it’s an advantage, since I have no plans to bequeath a cellar to my heirs and assigns, and I’d like to taste these wines while I still have functioning taste buds.
Well, like Tom, I am cellaring my wines for my own drinking, and my storage conditions are less than perfect. How do I decide when to open each bottle?

Some data

I decided that I would find out what sort of advice I get given. Since few commentators provide the required quantitative information (ie. some actual drinking dates), I ended up falling back on my trusty Australian wine experts (as I have done in previous blog posts).

There are three I found who have, at least in the past, provided a range of actual years that they consider to be the "peak drinking window" for the wines they have reviewed: Jeremy Oliver, James Halliday, and the Wine Front. The first two commentators are individual people, while the third one is a group of three people (Mike Bennie, Campbell Mattinson, Gary Walsh), any one of whom may have provided the commentary.

I have been recording their data whenever I consulted their writings about an Australian wine. So, there is nothing planned about the following data — it is simply whatever wines I have researched over the past couple of years, and for which all three critics have provided a minimum and maximum recommended drinking year. All of the wines are considered to be worth cellaring (otherwise I wouldn't need the data!), and therefore most of them are red (and, coincidentally, none are sparkling).

I got to a total of 111 wines, before I decided to write this post. I checked 194 wines, but only these 111 had complete data from all three sources. The following two graphs summarize the data for these 111 wines. Each of them is a frequency histogram, in which the vertical axis counts the number of wines fitting into each of the categories represented horizontally. The three commentators are shown in different colors.

The first graph shows the actual cellaring ranges suggested by each critic — that is, the number of years between their earliest suggested drinking date and the final suggested date (ie. the length of the drinking window). Note that, since it is the same 111 wines shown for each critic, the three superimposed graphs would be identical if the critics perfectly agreed with each other. Clearly, not only are they not identical, they differ quite a lot.

Frequency histogram of the cellaring ranges

So, there is not much agreement between the three sets of suggestions:
  • Jeremy Oliver's suggestions show two peaks of time (technically, the data are bimodal), with peaks at 4-5 years and at 9 years, presumably representing his idea about short- and long-term cellaring;
  • James Halliday's suggestions are also rather bimodal, but with peaks at 6 years and 9 years — plus, there are a lot of much longer times, as well;
  • the Wine Front suggestions are only slightly bimodal, with most of the suggestions being in the range 6-9 years.
So, it seems that, while the suggestions differ, it is the Wine Front that differs the most — Oliver and Halliday pretty much ignore 7-8 years as a storage time. Furthermore, for one-fifth of the wines there is actually no overlap in the suggested drinking window between: (i) the Wine Front and Jeremy Oliver, or (ii) between Oliver and Halliday. A fat lot of help this is to me, as a person seeking advice!

Now let's look at the data in a slightly different way. The second graph shows each critic's suggested drinking window as a proportion of the total suggested window — that total length is the number of years between the earliest suggested date from any of the critics and the last date suggested by any of them.

Frequency histogram of the cellaring range proportions

James Halliday is often the one who determines the maximum value of the window (represented by the big orange peak at the right), making him the most optimistic about how long the wines will last. Jeremy Oliver's suggestions are often only 40-50% of the length of the total window, while those from the Wine Front are often more than that. So, Oliver's suggested lengths average about 88% of those of both Halliday and 82% of the Wine Front's, while Halliday's average is about 27% longer than those of the Wine Front.

This means that Oliver is the most cautious in making his prognostications — he suggests shorter drinking windows. Perhaps he is less optimistic about the conditions under which wine will be stored by most people? Interestingly, Halliday no longer makes suggestions for the upper limit of his drinking windows. Perhaps he has realized that wine-storage conditions make this particular prognostication fraught with danger?


There is not much agreement between the three sources of cellaring information. This matches the situation for wine-quality scores, where disagreements among commentators abound, as I have discussed before.

I can see why most wine commentators refrain from being too precise about how long to cellar any given wine. Not only are they making a forecast about each wine's future development, they have to contend with unknown but probably less-than-ideal storage conditions. This is a pity, because I still have to somehow make my decision, every time I buy a bottle of wine. I can also see why wine-interested people often buy multiple bottles of each vintage — at least one of them might be drunk when the wine is at its peak!

Monday, August 13, 2018

Drawing lines through a graph of points — what does this mean?

The short answer is: it depends on who is drawing the line, and why they are drawing it.

Some time ago I published a post about getting the question right when analyzing data. I pointed out that the question usually leads to the choice of an appropriate mathematical model, which we then use to answer that question. We fit the model to the data (or the other way around), and reach some conclusions from what the model tells us. So, asking the right question will usually tell us something useful.

However, we need to think about the purpose of the model. Are we actually trying to create some model that helps us understand our data, or are we just trying to draw some line through a graph of the data? This is the difference between explaining our data and summarizing it, respectively (see An introduction to data modeling, and why we do it). Here, I will draw some different lines through a couple of wine-related data sets, representing different models, to show you what I mean.

Bordeaux wine production

Consider the following graph, which is taken from the American Journal of Enology and Viticulture 51: 249-261, 2000. It shows the total production of the Bordeaux wine region (vertically) over 60 years (horizontally). Each point represents one vintage.

Polynomial model fit

The authors have added a polynomial line to their empirical data, to illustrate the trend in wine production. The line fits the data quite well, with 89% of the variation in the data being fitted by the model.

This model may well be adequate for the authors' purpose (in writing the paper). However, it cannot be a realistic model for the data. For example, the model suggests that production decreased during the first third of the 20th century — indeed, it implies that wine production in 1905 was the same as in 1995, which is not what happened (see the actual Bordeaux history as discussed by the Wine Cellar Insider).

So, this is simply a "line of best fit" to the data, used as a convenience. It cannot be used to discuss wine production outside the range of years shown on the graph. That is, the line does not model wine production, but merely summarizes the available data.

If we wanted to model the actual wine production, then we would need a model (and line) that shows a small increase in wine production from the mid-1700s until the mid-1900s (since that is what actually happened).

As an example, consider the following graph of the same data, to which I have added two straight lines. One line fits the data until the mid-1960s and the other fits the data from then onwards. This is called a piecewise model (ie. it consists of a series of straight lines).

Piecewise model fit

The two lines of this piecewise model happen to intersect in 1968, which turns out to be the last year in which Bordeaux had a poor vintage. This intersection may thus not be coincidence. Indeed, Pablo Almaraz (2015. Bordeaux wine quality and climate fluctuations during the last century: changing temperatures and changing industry. Climate Research 64: 187-199) suggests that production management in Bordeaux changed during the 1960s, under which circumstances this new model would have some realistic basis.

However, this piecewise also cannot be correct, because it suggests that there would be a continuing increase in production during the 2000s, and we know that this did not subsequently happen. A sigmoid model would be needed, instead.

To illustrate what I mean by this type of model, let's look at the wine production of a single château.

Single château wine yield

This next graph plots some data for an unnamed wine producer, although only Château Latour fits the description given in the American Economic Review, Papers and Proceedings 101: 142-146, 2011. This time, wine production is shown for the 1840s until the early 2000s.

We can see that wine production increased during the 160 years of data, and we could, if we so inclined, fit a straight line as a "best fit". However, this line would fit only 50% of the variation in the data.

A more realistic model would be one that suggests little change in production until the 1950s, and little change in production from the 1990s onwards. Such a model is shown as the thick line in this final graph. Such models are known as sigmoid (the lines are shaped like the letter S) — technically, this one is a logistic model.

Logistic model fit

The model indicates that the long-term average production from 1850-1950 was c. 17 hL/ha. Production then rapidly increased to 45 hL/ha by 1990 (ie. a 3-fold increase). The mid-point of the increase was between the 1967 and 1968 vintages. This model thus fits the conclusions from the piecewise model quite nicely.

However, this model is probably not entirely correct, because it implies that Bordeaux wine production was unchanged in prior centuries, when it probably increased somewhat, from the 1700s.


There is a difference between fitting a line to the data (curve fitting) and trying to model the biology represented by the data. Both types of analysis fit an equation to a set of data, which is then visualized as fitting a line to a set of points on a graph. However, curve fitting focuses on finding the best-fitting equation, while modeling focuses on finding a model with a realistic biological interpretation.

Fitting a line is a mathematical procedure of convenience — it summarizes the data. However, the resulting equation may not have much direct biological relevance — the parameters of the model equation need to have a reasonable biological interpretation. In particular, a model should have relevance outside the range of the observed data — if the equation predicts values that are known to be incorrect, then it cannot be a good model for the biology, and nor can it be good if it predicts outrageous unknown values. A fitted curve is relevant only within the range of the data.

It is thus important to understand the purpose the author(s) had fitting the line, because this determines how we interpret the meaning.

Monday, August 6, 2018

Why not expand the 100-point scale?

Value judgments are usually presented on some sort of quantitative scale, with an upper limit of maybe 5 stars or 10 points, or even 100 points. In most cases, the maximum value represents the best quality that the evaluators expect to see.* This leads to a potential problem when someone or something achieves that quality. What happens next, now that we know the maximum can be achieved? What do we do when someone does even better?

For example, at the 1984 Winter Olympics the figure-skating pair of Jayne Torvill and Christopher Dean received maximum artistic-impression scores of 6.0 from each of the 12 judges, which had never happened before (for a single performance). Does this mean that no-one can ever do better? Not unexpectedly, the International Skating Union's International Judging System eventually replaced the previous 6.0 system (in 2004), so that scores no longer get near the maximum possible.

In a similar vein, it has been pointed out innumerable times that the top end of the 100-point wine-quality scale has become unnaturally crowded. This graph of the frequency distribution of some of Robert Parker's wines scores illustrates the issue (taken from my post Biases in wine quality scores). Here, the height of each vertical bar in the graph represents the proportion of wines receiving each score, as shown horizontally.

There is a distinct bump in the graph at a score of 100, indicating that more wines are being awarded this score than would be expected. This is precisely what happens when we reach the ceiling of any quality scale — there are lots of very good wines, and we cannot distinguish among them because we have to give them all the same score: 100.

We probably need to address this issue. Given the large subjective component in such ratings, there are only two general ways to go about this. We either:
  1. re-scale the 100-point scale, thus reducing the quality implication of the scores, so that "100-point wines" no longer get 100 points but instead get a wider range of lower points; or 
  2. go past the 100 limit, and start doling out scores that exceed 100 points.
This raises the question of whether the latter option has ever been chosen. Indeed, it has happened at least once that I know of (and there may be others).

In September 1998, Jancis Robinson posted on her web site a set of quality scores from a vertical tasting of the wines of Château d'Yquem (Notes from attending an Yquem vertical tasting).** The data are shown in the next graph, with the quality scores vertically and the wine vintages horizontally. The first two vintages were the "Thomas Jefferson wines" supplied by Hardy Rodenstock, and so their provenance is considered doubtful.

Jancis Robinson's wine-quallity scores for Château d'Yquem

The quality of the remaining wines is nominally scored on Robinson's usual 20-point scale. Note that three of the wines received a score of 20, while four of them were awarded scores that notably exceed 20 points (marked by the red line). Robinson made no comment about her unexpected scores, but she did use a series of superlatives in her tasting notes, the like of which we do not usually see from her pen (eg. "absolutely extraordinary").

Obviously, Robinson has her own personal quality scale, and what we are presumably being told here is that these wines exceed her usual expectations for a "20-point wine". It therefore seems to me that this is a prime example of option (2) presented above.

As such, the question does now rise as to whether this approach was actually necessary in this particular case. We might find a possible answer by looking at what other people have done when confronted with these same wines.

As one example, Per-Henrik Mansson published a set of quality scores for many of the same wines in the May 1999 issue of the Wine Spectator magazine (Three centuries of Château d'Yquem). He used a 100-point scale for his scores, so I have converted them to a 20-point scale for the comparison shown in the next graph (Mansson's relevant scores are in maroon).

Comparison of scores from Jancis Robinson and Per-Henrik Mansson

The correlation between the two sets of scores is 48%, which is slightly higher than we have come to expect from wine professionals (10-40%). However, Mansson never exceeded the nominal limit of his scale — of the 121 scores in his article, there are four 100-point scores, but none scored higher. Indeed, a comparison of the scores on the 20-point scale shows that Robinson's scores are generally 25% higher than Mansson's, across the board.

I think that we might therefore argue that Mansson has provided an example of option (1) presented above (ie. re-structuring the scale so that we don't bump our head against the score ceiling). Actually, Mansson provided nine scores that are <70 and 30 scores that are <80, so that he used a large part of the score range from 50-100 points (his lowest score is 55). This wide range of scores would be considered very unusual during the 20 years since he published his scores!

As a final note, there are only two vintages for which Robinson and Mansson strongly disagree — Robinson scored the 1931 vintage much higher than did Mansson, and he returned the favor with the 1971 vintage.

* This was not actually true at the undergraduate university I attended. The final (research) year of my science degree was assessed on a scale of 1-20. In this case, 20 points represented perfection, which could not be obtained in practice by anyone, let alone a student. Nor could a student get 18 or 19 points, although these might be obtained by a professional scientist. The best that might be expected for a student was 16 points, in which case the student was awarded the University Medal, which happened only occasionally. The top mark that might regularly be expected (ie. every year) was 14 points. At the other end, 0 points was a fail at the Honours year, which meant that the student would get a Pass award, instead.

** Thanks to Bob Henry for providing a copy of the blog post.