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.

©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 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.

©Wine -- Mise en abyme

Sunday, March 30, 2014

A generalized, grapevine-needs-driven, viticulture architecture

Orly Ashenfelter and Karl Storchman have recently completed a Working Paper titled Wine and Climate Change, portions of which I intend to highlight on this blog in the future. My goal going forward is to evaluate their findings in relation to a viticulture baseline but no baseline was presented as part of the study. I address that deficit in this post and will build the baseline around the grapevine needs presented in the table below.

Source: Compiled from

In addition to the needs listed above, the vine plant also requires a healthy environment in order to successfully complete its reproductive and vegetative cycles.


The climatic requirements for successful viticulture include: a growing season long enough to mature both the fruit and vegetative aspects of the plant; production of sufficient carbohydrates to ripen the fruit as well as to maintain future productive potential; and an adequate supply of water. Climate, according to Dr. Tony Wolff (Lecturer and Viticulturist, Virginia Tech) and John D. Boyer, is the average course of weather in a region over an extended period as measured by temperature, precipitation, and wind speed, among other variables (Vineyard Site Selection, Virginia Cooperative Extension).  Weather is itself defined as the state of the atmosphere at a specific point in time using the same variables as referenced in the climate definition above.  The climate of a grape-growing region will determine, to a large extent -- and all things being equal -- both the grape varieties that can be grown and the styles of wine that can be produced.

As it relates to the wine regions of the world, the ideal climates for vitis vinifera are Mediterranean and marine west-coast climates, both of which are characterized by mild, wet winters and warm, dry summers.  The mild winters promote long-term survivability of the vines (and increased quality of the juice as the vines age) and the wetness provides a reservoir of water that the vine roots can tap into during the grape maturation cycle.  The warm, dry summers provide the heat and light that are the engines of vegetative and crop growth while keeping at bay the threat of rot and flavor dilution that would accompany summer/fall rains.

Continental climates are modified by large land masses and are characterized by hot summers and cold winters.  Maritime climates, on the other hand, are modified by proximate large bodies of water which heat up and cool down at a slower rate than does the adjoining land mass.  This scientific fact results in the warming of winter winds as they blow over a warmer body of water and the warming of landside vineyards as the winds make landfall.  This warming could act to extend the growing season and minimize the potential vine impact of winter low-temperature events. On the other side of the coin, warm spring air blowing in over the still-cold water will be cooled down and will retard the development of landside vineyards, minimizing their potential for damage from spring frosts.

Two key grapevine needs are adequate sunlight and heat to allow both the fruit and the vegetative aspects of the plant to mature.  Vitis vinifera requires a minimum of 1250 hours of sunshine to provide ripe fruit. The progression of the grape through its various stages of maturity is influenced by the ambient temperature with research indicating that growth of the grapevine begins when temperature exceeds 10℃.  A measure -- growing degree days (GDD) -- has been developed to measure the accumulation of heat (as measured by temperature) in excess of 10℃ over a growing season.  Extensive research has yielded the following GDD parameters which can be used as input in vineyard site selection.

Source: Compiled from

A map of the distribution of grape varieties by growing season temperature is shown in the figure below.

Source: Susnik, Kajfez-Bogataj, and Kurnik, GIS
assessment of Climate Warming Impact onWine
Growing Regions, Workshop on climatic analysis
 and mapping for agriculture, 2005, Bologna, Italy
The canopy is comprised of the stems, leaves and fruit cluster (s) that comprise the most visible portion of the vineyard. Viticulturists manage this canopy as a means of ensuring a uniform vine structure and promoting the flow of air and sunshine within. The thinning and positionaing of leaves, stems, and fruit clusters during the summer ensures that all canopy elements have equal access to the available sunlight and airflow. A well-managed canopy should have one grape cluster per shoot --assuming an average size of 5 to 8 ounces per cluster -- and 10 - 15 leaves per shoot in order to ensure proper ripening.


Aspect refers to the prevailing compass direction in which the vineyard slope faces.  Aspect is important in that it affects the angle at which sunlight hits the vineyard and, as a result, its total heat balance.  For example, in areas with cool summers and a relatively low number of degree growing days, north-facing slopes will be facing away from the sun as it "moves" across the sky.  South-facing slopes, on the other hand, will have more direct access to the sun's rays over the course of the day.  In cool climates, slopes with southern aspects (S, SE, SW) allow vines to accumulate the maximum amount of sunshine as they pursue growth and fruit maturity. In continental climes, on the other hand, eastern, northern, and northeastern exposures are preferred.

Further, southern slopes warm earlier in the spring and this can result in early bud break and the potential for spring-frost damage.  On sunny winter days, the vines on south-facing slopes can warm up resulting in decreasd cold resistance and the potential for cold injury.

Mineral Nutrients

Adequate amounts of the appropriate nutrients are required to support proper growth of the grape vine, fruit development, and fruit maturity and those nutrients are obtained from the soil.  The table below shows the mineral requirements of the vine plant, the role of each mineral, acceptable ranges of each mineral in the soil, and the impact of mineral deficiency on the vine.

Source: Compiled from and others

Soil composition affects the availability of nutrients for soil uptake.  Soil pH is a measure of the acidity (3.5 - 6.5) or alkalinity (7.4 - 9.0) of soil which, through its influence on nutrient solubility and micro-organism activity, affects the number and types of nutrients in the soil. Soil pH between 6 and 7 is considered optimal for vine plant growth as most of the needed nutrients and micro-organisms are available in that range.  The optimal soil type also has a moderate content of low cation exchange capability (CEC) clay (Clay minerals act as harbors for nutrients because the positive ions of the nutrients are trapped by the negative charge of the clay minerals.  The abundance and types of minerals determine whether the clay is classed as low- or high-CEC.).


Water is a key player in the development and growth of the grape vine (soil component, key raw material in photosynthesis, nutrient carrier (both in the soil and in the plant), in-vine transportation vehicle, structural element of the vine). In cooler regions a vine needs approximately 500 mm water/year while the need increases to 750 mm/year in hotter climates. Key determinants as to how much water is actually delivered to the vine include vine density and soil water-holding capacity. Water can be delivered to the vine roots either as a result of precipitation or, in the areas where it is allowed, irrigation.

Air and Water Drainage


Elevation can be discussed either within the context of a specific location -- high point versus low point -- or in absolute terms -- feet/meters above sea level.  Regardless of the reference point, however, elevation can have a significant impact on vineyard temperatures; especially if the vineyard is located in a hilly or mountainous area.

Planting at or near the highest feasible points in the vineyard allows the viticulturist to meet the grapevine's need for good air and water drainage.  Cold air is heavier than warm air and will flow downhill to replace the warm air as it rises.  This air movement will cause the cold air to pool in areas of low elevation and can result in the formation of frost pockets.  In addition to shedding cold air, high elevations afford cooler daytime temperature during the summer and fall.  There is a point beyond which elevation becomes detrimental to the survival of the vine plant and planting at or above those levels are not recommended.  The optimal elevation range for grape vines to survive and thrive is called the thermal belt.

As in the case of air, water will flow from areas of high elevation to areas of lower elevation both on the surface and below.  This condition meets the vine's need for internal soil drainage.  Standard sub-surface water will limit the amount of oxygen available to the root system and can also destroy the small fibrous roots which are involved in the absorption of water and nutrients from the soil.


Slope is the degree of inclination of the land from the horizontal and a slight to moderate incline is desirable for air and water drainage.  Slopes in excess of 15 degrees will require (expensive) hand-harvesting of ripe fruit due to the danger of equipment rollover.   The costs of managing a high-slope vineyard need to be balanced against the style/type of wine the winemaker is after.  As has been shown in high-slope vineyards like Bremmer Calmont (Mosel) and Rüdesheimer Berg Schlossberg (Rheingau), the paucity of soil in these environments forces the vine roots deep in search of moisture and nutrients and this results in a desirable intensity of aroma, flavor, and terroir characteristics coupled with freshness. Slope effects can be ameliorated by terracing, an expensive proposition both in terms of establishment and maintenance.


According to Wolf and Boyer (Vineyard Site Selection, Virginia Cooperative Extension), the best vineyard soils "permit deep and spreading root growth" and provide a moderate supply of water year-round.  Mark Chien (Soil and Site Selection Considerations for Wine Grape Vineyards, Pennsylvania State University) posits that wine grapes do best in moderately fertile soils that are unsupportive of vigorous vine growth.  What are the soil characteristics that will permit "deep and spreading root growth" and year-round access to water?  Those characteristics are presented in descending order of importance in the table below.

The most important requirements, according to the table, are internal water drainage and water-holding capacity.  Geologic permeability (the capability of a porous rock or sediment to permit the flow of fluids through its pore spaces -- is seen by Wolf and Boyer as perhaps the most important consideration in a candidate vineyard's soil.  Chien sees well-drained soils as a  common denominator among all great vineyard sites.  These soils "strike a balance between adequate depth and drainage and water-holding capacity" and vines deployed therein will have adequate water access during the summer and can rapidly drain water from the soils in the event of rainfall during the grape-ripening period.  Vineyards sited on convex land patterns are preferable to those on concave landforms in that the former shed surface water while the latter import water as well as soils which erode from higher ground.

Vineyard soil fertility is one of those cases where more is not necessarily better. Adequate amounts of the appropriate nutrients are required to support proper growth of the vine, fruit development, and fruit maturity.  Fertile soils are generally rich in organic material and moisture.  In that grapevines are naturally vigorous, vines grown in highly fertile vineyards will produce abundant canopies and fruit but the fruit will be mediocre because of limited access to the sun and the vine having spread its resources too thinly. Most high-quality vineyards are sited on low-/moderate-fertility soils.

The next soil feature mentioned in the table is effective rooting depth.  The roots of the vine plant: i) anchor the vine; ii) absorb water and nutrients; iii) store nutrients that nourish the plant during dormancy; and iv) produce hormones that control plant functions. The vine deploys a three-part root structure to meet these varied needs.  First, quick-growing, short-lived roots deployed close to the service are tasked with moisture collection. Second, subterranean roots provide the anchoring function.  The principal roots are tasked with nutrient delivery and storage.  According to UCDavis, about 60% of the root structure of a vine plant can be found in the first two feet of the surface but individual roots can grow as deep as 20 feet depending on soil permeability, the level of the water table, and the rootstock variety.

Soil texture refers to the nature, size, shape, orientation, and arrangement of particles.  In the soil-type page I show that sand, silt, and clay have standalone properties which are transformed when the soils are combined.  Clay forms flexible elastic bridges between soil particles to maintain soil structure and preserve porosity.  Pebbles and rocks in clay-rich soils break up the soil, providing pathways for water and root penetration.  Deep, rich soils will provide high-vigor growth and large, watery grapes.

Soil pH is a measure of the acidity (3.5 to 6.5) or alkalinity (7.4 to 9.0) of soil which, through its influence on nutrient solubility and micro-organism activity, affects the number and types of nutrients in the soil.  Soil pH between 6.0 and 6.8 is considered optimal for vine plant growth as most of the needed nutrients and micro-organisms are available in that range.  Alkaline or acidic soils can be treated to bring them closer to optimal.

Click here to see my page on soil types of interest to viticulturists.

Pest- and Disease-Free Environment

The vineyard, left to its own devices, can become a haven for a wide range of pests and diseases with the potential for degradation of the quantity and quality of fruit produced. According to, the most effective means of combating diseases are (i) a good canopy management program and (ii) a rigorous preventative fungicide treatment program. A good canopy structure allows air circulation between the canopy components and rapid drying after rain or dew, or as a result of low humidity. Such an environment is less favorable for the development of fungal disease.

Establishment and Management of the Vineyard

A variety of factors will be considered in selecting the varieties to be planted in a new vineyard: (i) experience of other vineyards in the area; (ii) the quality of the variety; (iii) the sped at which the variety completes its annual reproductive and vegetative cycles and how do those cycles match to the climate of the region; (iv) the yield potential; (v) adaptation to climate; (vi) adaptation to soil conditions; (vii) its resistance to disease; and (viii) the varieties that are allowed by existing legislation (in an area where that is a concern). The common wisdom holds that varieties produce at their best when grown at the coolest margins of viable ripening.

Grapevines are selected either through mass or clonal selection and cuttings are grafted on to rootstocks based on the attributes required.

It is important that there be a balance between the vine root system and its canopy. In that regards, vines should be planted with higher density in poorer soils and less-densely in fertile soils. Many of the high-quality European vineyards are planted at between 5,000 and 10,000 vines/ha.

Vine pruning and training allows the grape grower to overcome the natural tendencies of the vine and force it to produce fruit that is more suitable to the production of quality wine. Canopy management techniques provide the berry with more or less access to the sun or protection from the elements as required.  For example, a significant challenge to Santorini viticulturists is the stiff wind that buffets the island during the growing season and could damage the berries if they were exposed to the elements. The solution that has been employed for eons is to (i) eschew vine density and (ii) train the vines such that they can afford protection to the otherwise vulnerable berries. Vine canes are intertwined and trained into a circle and the berries grow within this protective cordon. The circular structure can be positioned above ground or in a below-ground hollow where the top of the vine is parallel to the surface. A viticulturist has a wide variety of trellising and vine-training techniques available for deployment based on requirements.

©Wine -- Mise en abyme

Sunday, March 16, 2014

Saint-Péray AOC: A fount of bubbles in a still-wine sea

The Rhône wine region runs along its namesake river for 150 miles between Lyon in the north and Avignon in the south with a division into northern and southern sub-regions at the point where the Drôme tributary intersects the main course. Northern Rhône is characterized by a continental climate, granitic soils, steep slopes, and the Mistral wind while the south has a more Mediterranean climate and stony soils. What they both have in common, though, is a sea of red wine: only 2% of the region's production is white. And an even smaller percentage is sparkling. In my previous post I covered the sparkling wines of Die, but Die lies off the Rhône beaten path. In this post I will cover the sparkling wine of Saint-Péray, an AOC in Rhône's core.

Used with the permission of Syndicat de
la Clairette de Die et des vins du Diois 
Saint-Péray is an appellation (accorded 1936) for still white and sparkling wines produced in the parishes of Saint-Péray and Touland, neighboring communes in the Ardèche Départment of the Rhône-Alpes Region of Southern France. The region, located as it is three miles west of the town of Valence, is the southernmost of the Northern Rhône appellations.

The climate in Northern Rhône is continental, with warm summers and cold winters. While Saint-Péray exists within this climatic mantle, it is somewhat cooler than Cornas -- its neighbor to the north -- thanks to a cold wind -- Bise -- which flows along the Mialan Valley from an opening in the north. Average temperature in the region is 12.5℃ and average annual rainfall is 823 mm.

The Saint-Péray soil is a complex mix of limestone, clay-limestone, and granite which owes its composition to a number of donors ( (i) granite from the Primary Period contributes a hint of silica; (ii) Jurassic limestones from the Secondary Era; (iii) marine deposits from the Tertiary Period are the source of today's clay-limestone soils; (iv) a veneer of loess from the Quaternary Period and Major Glaciations; and (v) alluvial deposits carried down from the Alps by the Rhône River.

Saint-Péray vineyards extend over 75 ha of the gentle slopes on the right bank of the river at the foot of the limestone outcrop called Crussol Hill. The vineyards have a south to southeast exposure and are at altitudes that range between 107 and 652 meters. Regulations mandate minimum vine density of 4000 vines/ha.

The allowed grapes in the AOC are Marsanne (majority of plantings) and Roussanne. The characteristics of these two varieties are presented in the table below.

                                                  Saint-Péray Varieties
Marsanne Blanche, Grosse Roussette, Avilleran, Ermitage, Ermitage Blanc
Franceas Rousette, Bergeron, Plant de Seysel, Fromenteau
Site preference
Warm, dry, stony
lean soils; arid; rocky
Vigorous, high-yielding
Vigorous; semi-erect; sometimes fragile
Large; round; rough; 3-5 lobes; matte dark green upper surface, tufted lower surface
Medium to large; thick; 3 to 5 lobes; rough; Dark-green on upper surface, downy on lower
Conical, winged, medium-sized
Medium-sized; elongated; semi-cylindrical; winged
Small, round, thin-skinned; deep golden color on ripening
Small; round; sometimes irregular; golden with rust spots at maturity
Soft; juicy, sweet
High alcohol level; deep color
Light; dry; short-lived; added to Syrah to provide finesse; when combined with Roussanne, results in aromatic, delicate, interesting wine; toast, honey, and almond aromas
Blended with Marsanne; used in Vin de Paille; Lime and blossom aromas
Susceptible to disease; sensitive to temperature extremes
Low yielding; susceptible to rot; difficult to ripen; prone to oxidation
Sources: Grapes and Wines of the World,;

Sparkling wine production using the Traditional Method has been practiced in Saint-Péray since 1829. The grapes are harvested and then quickly transported to the cellar to prevent oxidation. After slow pressing, the juice is directed to vats or oak casks for fermentation and then to barrels or tanks for aging. Oak is used fairly commonly in the region in order to add complexity to the mix. Second fermentation occurs in bottle with the wine residing on lees for a minimum of 15 months prior to market release. Allowed yields are 52 hl/ha and a max of 11.5% abv for sparkling wine (The corresponding numbers for still wine are 45 hl/ha and 13%). Sparkling wines can be 100% Marsanne, 100% Roussanne, or a blend of the two. Blends are the dominant market-facing elaboration.

According to, 2012 Saint-Péray production amounted to 2686 hl ( yield attainment of 35 hl/ha) while sales amounted to 3008 hl, most of which was consumed domestically (9% exported).

©Wine -- Mise en abyme

Wednesday, March 5, 2014

Cremant de Die and Clairette de Die: Two faces of sparkling wine

In my continuing research on sparkling wine regions, I encountered Die, a wine region 30 miles off the Rhône beaten path, with sharply contrasting sparkling wine production methods. I share my findings regarding the region and its wines in this post.

The Drôme River is a tributary of the Rhône which, conveniently, serves as the dividing line between the wines of the north and south. Die, and its wines, are located in this river valley. Die produces both sparkling and still wines (Chatillon-en-Diois for reds and rosés, Coteaux de Die for whites) but it is in the sparkling wines that our interest lies.

Used with the permission of Syndicat de
la Clairette de Die et des vins du Diois 

Used with the permission of Syndicat de la Clairette de Die et des vins du Diois 

Die's climate can be described as Alpine Mediterranean because of the impact of both bodies on its environment. The region lies at the northern extreme of the Mediterranean climate and, as such, is subject to periods of extended warm weather and intense sunshine. On the other hand, its proximity to the Alps subjects it to rapid-development mountain storms and rain showers. In addition to affecting the areas' climate, the Alpine Mediterranean juxtaposition also contributes to a significant diurnal temperature effect.

The geographic environment is characterized by glacial rock formations and high cliff faces. The vineyards lie on a granitic base over which is overlain by chalky clays and sedimentary limestone rocks. The 1500 ha of vineyards all lie along the hillsides on both sides of the river and, end to end, extends over 31 municipalities. Elevations herein range between 200 and 700 meters.

The Die sparkling wine appellations -- Cremant de Die and Clairette de Die -- are described below.

Cremant de Die

Cremant de Die is the appellation for sparkling wine made in the Champagne manner and utilizing the following varieties: Clairette (55% minimum), Muscat Blanc à Petits Grains (5 to 10%), and Aligoté (10 to 40%). Production of this wine began in the 1960s and, until 2004, was restricted to Clairette only. The wine was awarded AOC designation in 1993.

Grapes for the wine are whole-bunch-harvested and then run through the traditional method. The wines are aged on lees for a minimum of 12 months with the norm being somewhere between 12 and 36 months. The finished wine is described as having rich aromas with notes of apple and green fruit and freshness on the finish. The altitude, limestone and clay soils, and temperature shifts results in high levels of natural acidity in the wine.

Over 40% of the region's sparkling wine is classed as Cremant de Die. The 13 producers involved in the business make 400,00 bottles annually with 85% of that production being consumed within France.

Clairette de Die

Clairette de Die is the appellation for a naturally sparkling wine made from Muscat Blanc à Petits Grains (75% minimum) and Clairette. This wine has a long history with AO status granted in 1910, AOC designation in 1942, and designation as "ancestral dioise process" in 1971.

Clairette de Die grapes are sourced from the same vineyards as are grapes for Cremant de Die. There are a total of 300 farmers involved in grape production, 250 of whom are associated with the Cave de Die Jaillance coop and the remainder either being part of smaller cooperatives or functioning as family farms.

The Clairette de Die production process stands in stark contrast to that of the Cremant de Die. The grapes are rapidly pressed and placed into vats where they are allowed to ferment at low temperatures. After 1 to 2 months, the fermentation is stopped -- the must still contains residual sugar -- and the proceeds bottled. This partially fermented wine is kept in bottle, at temperatures of approximately 12℃, for about 4 months during which time fermentation of the residual sugar continues. The carbon dioxide released during this fermentation is secreted in the wines and will provide the bubbles upon opening. Unlike the traditional method, there are no additives along the way.

Fermentation ceases naturally when the wine is about 7% to 9% abv and, at this time, the wine is ready for drinking. As there is no opportunity to manipulate the sugar content of the wine, it is only available in a Brut style.

©Wine -- Mise en abyme