Sunday, April 27, 2014

Harvesting: The most important decision for the winemaker

On of the most important decisions facing the viticulturist/winemaker is the timing of the grape harvest -- the so-called point of "optimal ripeness." As the starting point for the production of a quality wine, it is imperative that high-quality grapes be delivered to the cellar door. As noted by Wynboer, overripe as well as green grapes have a detrimental influence on the wine." As important as optimal ripeness is to the wine maker, there is no specific definition for the condition nor are there formalized mechanisms or technologies for determining its attainment. To further complicate matters, optimal ripeness will vary from winemaker to winemaker depending on (Bisson):
  • the style of wine being pursued
  • the working definition of quality
  • variety
  • rootstock
  • site
  • the interaction of variety, rootstock, and site
  • season-specific factors
  • viticultural practices
  • downstream processing events and goals.
With a "definition" of optimal ripeness in place, we can then turn to the identification of the relevant parameters. Dami has divided the criteria into two broad classes: objective and subjective. The objective criteria revolve around the components of grape juice at maturity, with sugar, acid, and pH being the primary indicators based on (i) abundance and (ii) ease of measurement.
  • Sugar concentration -- use of sugar concentration as the only measure of grape maturity ignores the contribution of a number of other elements to the perception of a quality wine. Also, there is not a one-to-one relationship between sugar and quality. According to Wynboer, Duplessis obtained quality differentials of between 8% and 27% with 4 years of Pinotage pressed at 22 °Brix.
  • Titratable acidity – actual amount of acid in the wine. According to Dami should fall between 0.6 and 0.8 gm/100ml
  • pH – measure of active acidity. Increases with increases in sugar concentration. According to Wynboer, not a reliable measure on its own. Should be between 3.1 and 3.3 for white grapes and 3.3 - 3.5 for red grapes
  • Ratio between sugar and acid – Wynboer sees this as more significant than any of the preceding alone. Jackson sees this as a requirement for a commercial-grade operation in a temperate climate. Bisson points out its variability across cultivars and a lack of clarity as to whether optimal acid:sugar ratios coincide with optimal flavorant maturity.
 The subjective criteria identified by Dami are as follows: color; ease of removal of berries from pedicel; texture; aroma; and flavor. These tests should be conducted by the winemaker during vineyard walk-through. Of the objectives tests mentioned, the test for flavor is the most important. Bisson sees optimal maturity as assessable only by monitoring flavorants themselves but such a task is laborious and expensive (Dami, Jackson) and has to be approximated through tasting (Wynboer, Dami).
Given that picking at optimal ripeness is critically important to the production of a quality wine, and that there are no mechanical/technological aids available to assist in accomplishing that goal, winemakers have generally turned to vineyard sampling as a means of: (i) testing the progress of the various berry components; (ii) predicting the optimal pick time; and (iii) to get a sense of the must after harvest. Under ideal conditions, the winemaker would test the fruit and, when the optimal ripeness is determined to have been achieved, harvest the fruit of the entire vineyard. But things are not so simple. Grapes in a vineyard do not ripen evenly – asynchronous ripening – signaling different development paths. This is a problem for the winemaker as both underripe and overripe fruit provide the opportunity for production of a lower quality wine.  At the vineyard level, ripening differences could be due to (Jackson): differences in vineyard age and health; inter- /intra-block differences in soil structure, texture, nutrition, and moisture content; and, the length of the flowering period. Variation between berries can be a function of (Zoecklein); berry size; berry composition; number of seeds; seed size; and berry position.
The goal of the vineyard sampling activity is to collect a sample that, when processed, will be reflective of the must composition. In order to accomplish this goal, the sample has to be large, representative, and positionally aware such that previously described berry and vineyard variabilities are accounted for therein. The consensus approach (Dami, Heller, Zoecklein, Wann, Watson) to sampling design and execution is as follows:
  • Devise the sampling scheme prior to entering the vineyard and, once there, stick with it
  • Sampling can be either berry-specific or whole cluster. If berry, collect at least 200/block. If cluster, collect 10 – 20 clusters.
  • Begin sampling about three weeks prior to the estimated pick date. Sample weekly, increasing frequency as you get closer in
  • Avoid sampling from end rows and odd-looking vines
  • Fruit should be selected from exposed as well as shaded locations at different heights and at opposite sides of the rows
  • Sample in the morning rather than in the afternoon. Dami sees a 1 °Brix difference.
Avoid the sampling flaws identified by Watson:
  • Collecting too few berries. According to Dami, two samples of 100 berries each are required to be within 1 °Brix of sugar at harvest
  • Collecting riper, mature berries. Again, will not provide a true picture of the post-harvest must
  • Sampling higher percentage of exposed berries. Neil points out that sun exposure of a berry, or the position of the cluster on the shoot, can influence maturity.

 Bisson, Linda, “In Search of Optimal Grape Maturity,” Practical Winery and Vineyard Journal, July/Aug01.
Dami, Imed, “Determining Grape Maturity and Fruit Sampling,” Ohio State OAROC Extension.
Hellman, Edward, “How to Judge Grape Ripeness Before Harvest,”
Jackson, Ronald S., Wine Science: Principles and Applications, 3rd ed., Amsterdam: Elsevier, 2008
Nail, William, Collecting Berry Samples to Assess Grape Maturity
Roller, Ben, “Pre-fermentation cold maceration,”
Wann, Grady, Live presentation on optimal ripeness
Watson, Evaluation of Wine Grape Maturity
Wynboer, “Optimum Ripeness in Wine Grapes,” May 2000,
Zoecklein, Bruce, Enology Notes #143,

©Wine -- Mise en abyme

Wednesday, April 23, 2014

Decline and fall of the Algerian wine industry: Filling in the study gaps

The French vineyards had been decimated by the Phylloxera infestation of the 1860s and Algeria had ridden the "magic carpet" of unfulfilled French consumer demand to the point where, in 1905, it was exporting 5 million hl of wine to France (50% of its total exports), fully 1/3 of its GDP.  A new Journal of Wine Economics paper (The Rise and Fall of the World's Largest Wine Exporter -- And its Institutional Legacy, Vol 9 (1), 2014), written by economists Giulia Meloni and Johan Swinnen of the LICOS Centre for Institutions and Economic Performance (Leuvin, Belgium), detailed the upward trajectory of the industry as well as its subsequent fall but, I contend, does not paint a complete picture in the rationale provided for the decline.  I reviewed their findings on the rise of the industry in an earlier post; in this post I cover their findings on the fall and flesh out the rationale palette.

After French producers had dug up their infected vines and replaced them with vines grafted onto American rootstocks, the Phylloxera threat abated. As production increased, wine prices declined significantly, falling 65% in the 25 years following 1880. French producers sought government relief and this came in the form of tariffs on Italian and Spanish wines imported into the country. Italian and Spanish wine imports declined as a result of the tariff-driven price increase and this led to further increases in the volume of Algerian exports as French consumers substituted Algerian wine for its more expensive competition.

World War I and the spread of Phylloxera to its vineyards took Algerian wine off the table as an issue for French producers; Algerian production fell from 10 million hl pre-war to 5 million hl in 1922. But this was a temporary state of affairs as rapid adoption of the American-rootstock technique, significant expansion in vineyard area (175,00 ha to 400,000 ha from 1925 - 1935), and high wine prices in France (23 francs/hl in 1921 - 1925; 32 francs/hl, 1926 - 1930) saw production grow to 20 million ha in 1935. Production declined to 1922 levels in the middle of WWII but was back up to 18 million hl by 1953.

On Algeria's independence in 1962 it had 360,000 ha under vine; by 2005 that number had declined to 25,000ha. Production was 15 million hl at independence and 600,000 hl in 2009. Exports were 14.8 million hl at independence and 17,000 hl in 2008. To what forces were these precipitous declines attributable?

Production (blue) and export (rust) data for the Algerain wine
industry. Smoothing obscures inter-point volatility.
Selected data points from Meloni and Swinnen time series

Selected data points from Meloni and Swinnen time series.
Smoothing obscures inter-point volatility.

According to Meloni and Swinnen:
  • Export constraints after independence. France had agreed to purchase 39 million hl over 5 years but, encouraged by domestic producers, failed to meet its obligations under the treaty.
  • Poor management after the wine industry was nationalized
  • The inability to find substitute markets. A deal in 1969 to supply the Soviet market was abandoned due to profit pressures.
While the authors mentioned poor management as one of the main reasons for the failure of the industry, they do not provide any quantitative or qualitative data to back up that assertion. Further, they failed to mention a number of potentially critical elements of the decline.

First, these selfsame authors had attributed the rapid growth of the Algerian wine industry to the 50,000 families entering the country after the Phylloxera infestation in France, bringing critical winemaking and management skills to the country. Is it not likely then that the 900,000 European Algerians who left the country after independence might have taken some of those skills (remember 97% of the vineyards were owned by French settlers) with resultant short- and long-term negative implications for the industry? asserts that the Algerian wine industry was "severely handicapped by the sudden loss of foreign managers and skilled labor." In addition, many of the Algerians who had worked closely with the French pre-independence either fled the country or were killed shortly after independence. Could some winemaking and managerial skills also have been lost in this manner?

Second, the authors stress the loss of the export market but Algeria lost its domestic market also when the 900,000 Algerian-Europeans went home. And that market would never be coming back.

So these guys were screwed: they had lost their only export market; they had lost their domestic market; and they had lost the critical winemaking and management skills of the foreigners and locals who had "fled" the country. Add to this the "government view that dependence on wine was probably inappropriate for a muslim state" ( -- another rationale that the authors failed to mention -- and you end up where Algeria is today. According to the authors, "From a global perspective, the Algerian wine industry has 'effectively disappeared.'"

This study was, overall, very digestible. It was an "old school" study which eschewed econometrics and mathematical economics in favor of time series data and associated analysis. I had some issues with the paper though. First, it seemed as though the authors tried to cram three separate studies into one: (i) The rise and fall of the Algerian wine industry; (ii) the bi-directional flow of wine-related legislation as it relates to France and Algeria; and (iii) the role of French wine regulation in shaping the direction of European -- nay worldwide -- wine regulation. Second, the authors failed to at least advance some of the decline-and-fall narrative that I have provided; and (iii) a little bit of modeling (using regression analysis and dummy variables) would have helped us to understand the relative importance of the provided reasons for the decline and whether other heretofore unidentified factors also contributed.

©Wine -- Mise en abyme

Sunday, April 20, 2014

The rise of the Algerian Wine Industry

In his otherwise excellent history of wine (Reinventing Wine), Paul Lukacs failed to mention that 1960s Algeria was the world's largest wine exporter and its fourth largest producer. Further, while he described his version of the formulation of the French appellation system at great length, he did not mention the catalytic role of the Algerian wine industry in its development. These two points, along with many others, are detailed in a new Journal of Wine Economics paper (The Rise and Fall of the World's Largest Wine Exporter -- And its Institutional Legacy, Vol 9 (1), 2014) written by economists Giulia Meloni and Johan Swinnen of the LICOS Centre for Institutions and Economic Performance located in Leuvin, Belgium.

The French conquered Algeria in 1830 and managed it as a colony until granting it independence in 1962.


With French colonization, Algerian viticulture began to grow, with settler and colonists alike drinking the beverage because of its perceived safety and medicinal benefits. The country's warm temperature retarded development, however, and it was not until the introduction of the "cold fermentation" technique (allowing complete fermentation of the harvested grape) that serious commercial viticulture could be undertaken.

The introduction of cold fermentation, coupled with the devastation of French vineyards by the Phylloxera louse, lit a fuse under the nascent Algerian wine industry. Phylloxera caused a 70% decline in French wine production but this loss of capacity did not result in a diminishing of the French consumer's demand for wine. The combination of lost capacity and continued high product demand resulted in the following state of affairs:

  • Increased demand for Algerian wine as France filled its 15 million hl demand shortfall with imports and adulteration. Imports increased from 1.2 million hl in the 1865-1869 period to 10.6 million hl in the 1875-1879 period.
  • 50,000 French families emigrated to Algeria and took control of 700,000 ha, much of it destined to become vineyards
  • An exponential increase in the level and amount of winemaking skills now resident in Algeria.

The Bank of Algeria was also a key enabler in the expansion of Algerian wine production as, in this timeframe, it overcame its previous reluctance to provide capital to the industry.

Initially, France's European neighbors also benefitted from its demand gap but as Algerian production ramped up, their fortunes fell off. While Algerian exports to France rose to 5 million hl in 1905, it was almost zero from Italy (down from 1.5 million hl in the late 1880s) and 2 million hl from Spain (down from 7 million hl in the same timeframe). For Algeria, by the turn of the century, 1/3 of its GDP, and 50% of its exports, revolved around wine production. By 1933, that export percentage had risen to 63%.

The charts below show production and export of Algerian wine and the area under vine. The details behind the charts will be discussed in a later post but the take-away here is the massive increase in all three measures from the starting point in the late 1800s.

Production (blue) and export (rust) data for the Algerain wine
Selected data points from Meloni and Swinnen time series

Selected data points from Meloni and Swinnen time series
I will cover the issues surrounding the fall of the Algerian wine industry in a subsequent post.

©Wine -- Mise en abyme

Friday, April 18, 2014

French wine quality: From thin air to a weapon of war

In a recent post I touched briefly on how the French appellation system had evolved into a standard of quality. Recent research has pointed out that this was not a benign evolution. Rather, quality was used as a hammer to dispose of the ongoing threat posed to the well-being of the French producers by the Algerian wine industry. And succeed it did. But that success is the story of another post. In this post I provide further detail on the origins of the appellation system, drawing heavily on the work of Guilia Meloni and Johan Swinnen (The Rise and Fall of the World's Largest Wine Exporter ..., Journal of Wine Economics, Vol 9 (1), 2014), both economists at the LICOS Centre for Institutions and Economic Performance in Leuvin, Belgium.

At the turn of the 20th century, the French wine industry appeared to align along three poles: the establishment (Bordeaux, Burgundy, and Champagne producers); the French south; and Algerian producers. And these groups had all "lawyered up" for the battle-royal in which they were engaged.

Selected Turn-of-the-Century French Wine-Producer Organizations
Fédération des Syndicats de la Champagne
Syndicat du Commerce des Vins de Champagne
Association Viticole Champenoise
Southern France
Syndicat des Viticulteurs (1887)
Confédération Génerale des Vigneros du Midi (1907)
Confederation des Vignerons des Trois Départments Algériens
Source: Meloni and Swinnen

According to Meloni and Swinnen, the continental French producers wanted to reduce/eliminate imports from Algeria because of its pricing effect (Bordeaux and Burgundy producers) and similarity of offering (Southern France producers) and pushed the French government, over a number of years, to enact legislation which resulted in the attainment of their goals.

The first of what Meloni and Swinnen call "Quality Regulations" arose out of the so-called "Leakey Affair" wherein Algerian producers had contracted with a British merchant to sell their wines in England. With Algeria being a French Colony, Mr. Leakey took the liberty of advertising the Algerian wine as French and this angered continental French producers when it came to their attention. They accused the Algerian producers of being in cahoots with Mr. Leakey in this "false advertising" campaign and, further, accused them of producing "non-natural, artificial" wine. One month after the Leakey contract went into effect, the French government passed the Frauds and Falsification Law of August 1905 which stipulated that French wines sold commercially had to indicate its origin on the label.

Once this law was in effect, the producers hastily pursued the advancement of their interests by championing laws which tied the quality of a wine to (i) its place of production and (ii) the traditional wine producing methods of that (those) place(s). To take full advantage of the new reality that had been created on the ground, Bordeaux, Cognac, Armagnac, and Champagne were demarcated between 1906 and 1912 and began to be referred to as appellations (The Champagne boundaries were not finalized until 1927 when Aube kicked the doors in. The Champagne case was a little different than the case of the still-wine producers but the motivations were similar. The Champagne Growers felt that the Champagne Houses were bringing in "foreign wines" and calling it Champagne so these quality initiatives advanced their cause also.).

Once the foundation had been laid, the legal terroir was extended and solidified by a series of additional "quality laws":
  • A 1919 law made it illegal for an unauthorized producer to use an appellation name
  • A 1927 law restricted the varieties and viticultural practices that could be used for appellation wine
  • A 1935 law created the AOC system which:
    • combined earlier legislation
    • stipulated regions, variety, minimum alcohol content, and maximum vineyard yield.

With the passage of the 1935 law, the French producers had completed the journey from selling whatever they could get their hands on to developing a framework which, on the surface, seemed altruistic and consumer-friendly, but, in reality, was a tremendous barrier to entry. Quality is a high-value, desirable word and who would fault the producer for pursuing quality? Only the ones who are frozen out by the "quality" initiatives. But who is listening.

Today we think of the French AOC system as being definitive of the taste of a region and, to some extent, a designator of quality wines. But that is only the part of the iceberg that is visible above the surface. Beneath the waves this is a significant barrier to entry which, in addition to saying who is in, serves to effectively keep the "other" out. This system was formulated initially by the French wine-producing establishment as a series of geographic exclusionary zones which were then legally reinforced with "quality" characteristics, made unique with variety and viticultural restrictions and, finally, with the AOC laws of 1935, codified for the state and, eventually, the rest of Europe.

Telecommunications providers have this old adage around bandwidth -- Build it and they will come. The French producers built this. And we all came.

©Wine -- Mise en abyme

Monday, April 14, 2014

A brief history of terroir (After Lukacs)

So I am taking a class and we were asked to discuss selected aspects of terroir. Having read Lukacs Reinventing Wine -- and been impressed with his treatment of terroir therein -- I will use his work to explore the topic from an historical perspective.

Let us begin with a definition of terroir. According to Lukacs, this is a fairly modern term which has its roots in the Latin word terratorium and was used in France to mean territory. During the 19th century additional meaning was placed on the original skeletal framework where the word was now used as a descriptor for an "area of land valued specifically for agricultural properties." In the 1900s terroir began to be used as a designator for a vineyard's natural environment and to characterize the wines made from the grapes grown therein. According to Lukacs' research (summarized graphically below), modern wine did not arise until the advent of the relevant scientific and technological advances of the Enlightenment.

Prior to that period, wine drinkers consumed oxidized, sour wines which were "fortified" with all manner of additives designed to either slow its decay or make it more "palatable." Even in those days, however, there was some sense of preference for wines from specific areas: in Classical Greece, the Aegean Isles; in Rome, initially, wines from the south and then, later in the empire, wines from sub-regions (Falernum, for example) of the Bay of Naples or Latium. These wines were from broad geographic areas, would have been awful to our modern palates, and the appreciation would have been as much for the additives as it was for the wine.

According to Lukacs, the "first wines prized for their ability to display ... individualized aroma and flavors" were made in Burgundy by the Cistercian order which had been founded there in 1098. This order was focused on piety and hard work and devoted a lot of effort to tending their vineyards. Over the course of many vintages, these monks were able to identify the characteristics of individual vineyard plots and to note that these differences were, in some cases, manifested by "only a few steps separating an excellent grape-growing spot from a merely good one." The monks marked out these plots by their differences, in some cases building a stone wall to create a "cloistered vineyard." Lukacs takes the position that the monks did not intend that their demarcations single out one vineyard as better than the other. Rather, they were saying that the grapes sourced from these vineyards made reliably noticeably different wines and they thus needed to be so identified.

The wines from Clos Vougeot and other Cistercian crus were perceived as being so different as to be worth the trouble and expense of overland shipping to the relevant markets or waterways for onward transit.

While the grapes grown in that time/space clearly demonstrated terroir differences, it is not clear that the wines had the same experience. Not for long anyway. After all, the winemaking practices at the Abbey was still normative and the rudimentary production and storage techniques still made wines susceptible to the pull of vinegar. As shown in the figure below, the Burgundian wine of that era was still classed as "Ancient" and, as such, the over-riding characteristics would have been oxidative and acetic. If these were the dominant characters, is it possible that, even in those days, marketing reigned supreme where terroir was concerned because I find it hard to understand "more finely oxidized" or "elegant acetic."

Burgundy has had a long tradition of vineyard-specific crus and associated wines, a luxury that was denied Bordeaux. And the Burgundy tradition translated into desired wines and high prices. Bordeaux saw tradition as the "value proposition" and set out to have its wines don that mantle. It began with Arnaud III de Pontac doubling the price of the wines from Haut-Brion in 1660 because his estate, he said, was "special." There was no contemporary evidence to back up his claim of "specialness" but his calculation was that if his wines were bought at that elevated price, the buyers would not have the gall to adulterate it with "lesser wines" prior to sale to the final consumer. Rather, they would aid him in the projection of the special nature of his wine by selling it into the market at that elevated price plus a markup. This was pure marketing. Madison Avenue would have been proud of this guy.

The rest of the Bordeaux establishment built on this brazen arrest and seizure of quality by stipulating that consumers buying from the Chateaus were assured of quality wines because of the tradition of producing same. So while the vineyard site may expand or contract, and the fruit may be sourced from different plots in the vineyard, the Chateau remained constant; and so would the quality of the wine. The cru in Burgundy was a vineyard or plot; the cru in Bordeaux was a myth. The wine in Burgundy was a mono-varietal; the wine in Bordeaux was a blend.

A number of other European wine regions saw how Bordeaux has successfully re-invented itself and wanted in on the action. So they either brought French winemakers to their territory or went to Bordeaux themselves so that they could learn the "tricks of the trade." Examples include Piedmont (1843), Biondi-Santi in Montalcino, and the Rioja region of Spain.

What Lukacs termed the First European Golden Age of Wine came crashing down around the continent's ear after the visitation of a series of vineyard pests and diseases beginning with Phylloxera  in the 1860s.

The period post the 1860s, and into the Early Post WWI, was characterized by widespread misrepresentation of the wines that were being sold to consumers. This cheating was hurting the image and the pocket of responsible French growers so they began to seek the government's aid in developing mechanisms that would reassure the customer as to what he/she was buying. Lukacs: "The original rationale for demarcating particular regions as the source of particular wines had been a desire for authenticity. By requiring that only wines made in specific areas be identified as such on labels or invoices, the French authorities tried to halt the sale of counterfeit cuvees."

With the passage of time, officials began to pack additional requirements onto the original framework to include items such as the varieties that could be used in the region, how they should be planted, the yield, how the wine should be made, and how it should taste. As a result of these practices, the particular taste of the region's wine was solidified. Lukacs again: "The appellation system became a mechanism for a legally sanctioned hierarchy of quality." It improved French wine by "distinguishing those that employed a genuine particularity of aroma and flavor from those that did not." One of the other facets of the French AOC system was that it also, for the first time, made quality wine available at the table of the common man. All of the other European countries instituted similar sytems to regulate their local wine industries.

New world wines did not begin to compete effectively with French wines until the 1970s and 1980s and their vintners did not set much store by the French focus on the double-T's -- terroir and tradition. They instead stressed the double-V's -- variety and vision. A classic example is Penfold's Grange, the grapes for which are sourced from a number of disparate vineyards but yet, year after year, produces a distinctive wine with an immediately recognizable flavor profile. This was, according to Lukacs, a testament to the winemaker's vision and execution.

Based on the foregoing, terroir, as construed today, differs significantly from its origins and intent. The Cistercians demarcated their vineyards to show differences in grapes grown there and, as a result, established a tradition of Burgundian wines. I maintain that they initially established a tradition of Burgundian vineyards -- because the wines should have been indistinguishable from others due to oxidation and sourness -- and that evolved into a tradition of Burgundian wines. Somewhere along the way there was a successful marketing effort to traditionalize the industry and then to monetize that tradition. Bordeaux recognized the pecuniary benefits of traditions and sought, successfully, to establish its own. They did not spend the hundreds of years getting to understand the characteristics of their vineyards -- as the Burgundians had done. They just claimed it. The AOC system, set up to deter counterfeit wines, evolved into a "deviser" of taste and quality. It was not set up around terroir. Rather, terroir was devolved upon it.

New world vintners rightly eschewed pursuit of terroir and tradition in their winemaking efforts. They were not confronting the same issues or experiences as had their old-world brethren. Yet they have been able to turn out wines of high quality. Should these winemakers pursue the adoption of terroir wines? If they want to. But I have seen no scientific evidence which shows a "terroir effect" The research which has been done by Maltman, for example, shows no correlation between vineyard soils and grape/wine composition. To my mind, terroir is all about tradition and monetization of same.

©Wine -- Mise en abyme

Friday, April 11, 2014

A high-level map of the sources of wine aroma

A while ago I had set out on a journey aimed at comprehensively describing all of the attributes of a quality wine and had developed the below framework as a series of guideposts towards this end. I had covered most of the intrinsic factors -- with the exception of aroma/flavors -- when I got sidetracked by items which piqued my interest along the way. I am now ready to return to this task, prompted in large part by some excellent research work on aromas that has come to my attention recently.

According to Robinson et al., (Origins of Grape and Wine Aroma. Part 1. Chemical Components and Viticultural Impacts, Am. J. Enol. Vitic, 65:1 (2014)), "The sensations of flavor occurs when odor-active molecules stimulate sensors in the mouth and nose, which the brain collates to produce a flavor perception." Olfactory, gustatory, and trigeminal assets cooperate in order to produce the perception of flavor but, according to the authors, smell plays an outsized role "in the overall perception of the product." Smell, as defined by the authors, "is a biological and electrophysiological process that converts the molecular information of an odorant into a perceptual response."

We continue with some baseline definitions. An odor is a volatile compound, or combination of volatile compounds, that stimulates the olfactory organ to register a smell. The odor threshold of a compound is the lowest concentration at which its smell can be detected. The perception threshold is the minimum detectable concentration for 50% of a group of tasters while the recognition threshold is the minimum concentration of that compound necessary for identification of the odor.

If we relate the foregoing to wine, quality wine can be characterized as having complex associations of aroma compounds that exceed the odor threshold; and, for a subset of tasters, exceed the recognition threshold. But what are the sources of these odor? The figure below captures those sources at a high level.

As the figure shows, wine odors are the sum of the odors from the grape, maceration, yeasts, alcoholic fermentation, malolactic fermentation, and aging. Additionally (discussed as an odor source by Robinson et al., but not described graphically above), "chemical changes associated with acid and enzyme-catalyzed modification of both non-aroma-active and aroma-active grape constituents" are also sources of wine odor. The Wine Institute characterizes these odors as shown in the table below.

Over the course of a number of future posts I will delve deeper into these sources and attempt to show how the interaction of the odor compounds aid in the perception of a quality wine.

©Wine -- Mise en abyme

Sunday, April 6, 2014

Wine and Climate Change: A review

Orley Ashenfelter (Joseph Douglas Green Professor of Economics, Princeton University and President of the American Association of Wine Economists (AAWE)) and Karl Storchman (Clinical Professor of Economics, New York University and Managing Editor, Journal of Wine Economics), having both written extensively on the economics of grape growing and wine production and distribution, recently collaborated on a study of wine and climate change. That study, succinctly titled Wine and Climate Change (AAWE Working Paper No. 152, March 2014), utilizes comprehensive literature surveys to: (i) identify the projected physical impacts of climate change on viticulture; (ii) illustrate the associated economic impacts; (iii) proffer adaptation strategies; and (iv) identify potential winners and losers. I will use the findings of this study to determine what changes, if any, will be imposed upon the baseline viticulture architecture (shared in my previous post) as a result of the identified impacts and effects of climate change. Given the makeup of the viticulture architecture, the scope of this effort will be limited to the physical effects of climate change, adaptation strategies, and winners/losers. The economic impacts, while intriguing, do not lend themselves to inclusion/comparison against the viticulture model.

Ashenfelter and Storchman assessed the physical impact of climate and weather along four planes: Temperature, Carbon Dioxide, Pests, and Water. Before reporting on the findings in each of these categories, however, I would like to revisit my architectural framework in light of some of the ideas advanced in the paper.

In my post on viticulture architecture, the Adequate Sunlight and Heat component (see below) would appear to encompass the first of the four analysis planes mentioned above.

While my focus in the architectural baseline was on the temperatures required to promote the vegetative and reproductive aspects of the grapevine, the authors additionally stress the importance of the dormancy period which occurs when temperatures fall below 10 degreesC (50 degreesF). According to the authors, winter dormancy: (i) helps to sybnchronize the growth stages of the vines and (ii) increases the productive lifetime of the vine. The authors illustrate the importance of this dormancy period by comparing grapegrowing in the tropics to grapegrowing in traditional quality-wine zones. In the tropics, a lack of dormancy can sometimes allow two or more crops annually, according to the authors, but, in addition to the grapes not being suitable for wine making, is also accompanied by a host of issues that are not common in the traditional regions. The key finding here is that my viticulture architecture will need to be expanded to accomodate a dormancy period.

Physical Impacts

The key climate and temperature impacts reported by the authors are as follows:

  • All varieties exhibit lower fruit-set, ovule fertility, and berry size as temperatures exceed 25 degreesC (77 degreesF)
    • This suggests that warming above cultivar-specific optimums reduces crop yields
  • High temperatures increase grape sugar accumulation and reduces grape acidity
  • Enzymes that initiate the physical softening of berries and contribute to the accumulation of flavors, aromas, and pigments can be inactivated or destroyed by very high temperatures
  • Increased warming may increase the number of good vintages in cold-climate wine growing regions while simultaneously decreasing the number of good vintages in hot-climate growing areas
  • Extreme temperatures, at both ends of the spectrum, will be detrimental to the vine plant or grape.
  • Substitution capability diminishes with increasing heat.
Carbon Dioxide:
  • No demonstrable impact to grape vines or berries as a result of increased levels of carbon dioxide (Editor's Note: other than everything that we are talking about, that is).
  • Warming temperatures are likely to increase disease and pest pressure on grapevines
  • The incidence of fungal diseases (black rot, downy mildew, etc.) will increase with warmer weather
  • IPCC expects increasing water deficiencies in most grape growing areas.

In the foregoing list, carbon dioxide has no clear effect on the grapes while the threats presented by water and pests appear to be things that could be fought with the tools we have in hand today. The issue of most concern then, as it relates to the physical impact of climate change, is increasing temperature.

Selected Economic Effects

While the bulk of the economic analysis is beyond the scope of this paper, I would like to point out a few of the economic effects noted by the authors because they are straightlined from the physical impacts and then feed into the further discussions of price and profits. One of these areas is the availability of suitable vineyard areas in the the face of the physical impacts of climate change. One of the studies cited by the authors (White et al., 2006) posit a reduction of suitable vineyard area in the US from 4.1 million square kilometers to 3.5 million square kilometers by the end of the 21st century. For the highest quality growing regions, White et al., see a reduction of 81% in suitable growing areas in the US. Further, as suitable areas migrate to more humid and higher-precipation areas, higher levels of funding will be required to keep fungal diseases under control. It goes without saying that with less vineyard space, and increased costs of keeping pests and diseases from the remaining space, the implications for costs are immense.

Another proposed temperature effect revolves around yields. The standard for high quality grapes is to manage yield down but, according to one of the studies cited by the authors, a 3 degreeC rise in temperature could result in a 90% increase in yields in the coastal California area wine growing regions.

Finally, the authors discuss quality implications for various wine regions as a result of temperature increases. They foresee quality improvement in the wines of currently cool climes like northern France and Germany while they see a simultaneous decline in quality in the Rioja region of Spain, California, and South Australia.

Potential Adaptation Initiatives

The authors' proposals for adaptations to combat climate change can be classed as tactical and strategic (or, more colloquially, "shelter in place" and "get the hell out of Dodge") and are presented in the table below.

                     Potential Adaptation Initiatives
Harvest date shifts
Movement towards the poles
New cultivars and rootstocks
Movement to higher elevations
Use of canopies to mitigate the sun’s effect

Row re-orientation

Cover crops between rows to reduce reflected heat

Source: Derived from Ashenfelter and Storchman AAWE Working Paper

While harvest-date shifts, increased canopy size, and cover crops have relatively low cost implications, the same cannot be said for the other tactical adaptations. First, at the warmest extremes of today's viticultural environment, cultivar substitution is not a realistic option. Secondly, cultivar substitution and row re-orientation have both direct and opportunity costs associated with replanting and then waiting for the new vines to become contributing members of the vine society.

In the case of the strategic solutions, the authors point out a number of issues and gating factors which will have to be addressed along the way. In the case of the US, the authors see the Rocky Mountains and the border area between Washington and British Columbia as becoming viticultural desirable as traditional wine-growing areas become warmer. Movement to these areas, however, will place the viticulturist into conflict with native flora and fauna. In the case of Europe, the issues that would have to be addressed include:

  • The tying of cultivars to specific appellations
  • Irrigation prohibition in many appellations
  • The need for planting rights in order to plant vines anywhere in Europe
  • The EUs historical reluctance to award new planting rights

The American public and its representatives continue to take a "see no evil, hear no evil" approach to climate change and while viticulturists cannot on their own change the course of history, they would be guilty of negligence if they were not planning for the future that will be. The Ashenfelter and Storchman Working Paper, in the IPCC style, uses a broad range of research to provide an updated picture of the implications of climate change for the wine industry and potential paths forward. While not fine-grained enough to surface potential changes to the needs-driven viticulture architecture, it provides a strong sense as to where the strategic viticulture focus should be: on the site selection and vineyard establishments aspects of viticultural science.

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