The many roles of water in grape vine growth and development

Water is a key player in the development and growth of the grape vine.  In this post I highlight its many roles.

Soil Component

Soil is comprised of air, water, mineral particles (a mix of clay, silt, and sand), organic matter (decomposing plant material), and organisms (bacteria, algae, fungi, earthworms, insects, etc.).  Half of the overall soil content is pore space, a 50-50 mix of air and water. Organic matter is, in addition, a reservoir of nutrients and water.

Soil-based nutrients are resident either in the soil solution (water and dissolved minerals in the soil pores) or in the soil matrix (mineral particles and organic matter).

Raw Material for Photosynthesis

Along with carbon dioxide and sunlight, water is a key raw material in photosynthesis, the process by which the grape vine produces its needed energy.  In photosynthesis the hydrogen and oxygen molecules are split apart by light energy and the hydrogen combines with the carbon, leaving the oxygen as the waste matter in the process.

Chloroplasts, the sub-cellular structures within which the process occurs, is found primarily in the leaf of the vine but is also contained in the stems and reproductive organs. With the largest surface area of the vine, leaves are its most significant producers of carbohydrates.

Photosynthesis can be slowed or stopped in the event of a water deficit.  Such slowing or stoppage will have a negative effect on vine vigor.

Transport Vehicle

Through the process of transpiration, water serves as a vehicle for moving material into, within, and out of the vine plant.  Water enters a vineyard through precipitation or irrigation and that water either runs off, flows to levels beyond which it can be accessed by the vine plant, or remains in the rooting zone where it is available for the plant's use. The plant uses water as an internal distribution vehicle (in addition to other functions) and facilitates this by expelling water through pores (stomata) in the leaves.  As water is transpired from the leaves, replacement water is drawn in at the roots.

Source: talktalk.co.uk

Water attracted to the vine root by transpiration moves undiluted nutrients to the root surface (bulk flow) but also carries dissolved nutrients into the roots as a part of its transit. Nitrogen is the nutrient most frequently acquired by the roots in this manner.  Nutrients are moved up from the roots to needed areas through the phloem by transpiration.

Photosynthates, the products of photosynthesis, are used to fuel vine growth and maintain plant functions and are allocated to various parts of the vine based on need.  A net producer of photosynthates is referred to as a "source" while a net consumer is called a "sink."  According to Lebon et al., there are two phases to the annual cycle of grapevine physiology.  In Phase 1 starch is mobilized from the woody parts of the plant to supply the annual organs with carbohydrates to sustain their growth.  In this case, the majority of food material is first sent to actively growing areas (shoot tips, developing fruit, root tips). Phase 2 is initiated when photosynthate production exceeds the needs of the vine. The excess production is routed to the woody (roots, trunks) parts of the vine for storage.  The berry cluster is the main sink for photosynthates during ripening while the woody tissues are the primary sinks post-harvest.  The process of moving photosynthates between sources and sinks through the xylem is called translocation and is enabled by the previously described transpiration process.

Solvent

Nutrients and sucrose are in solution for carriage through the vine.

Air Conditioner

Ninety percent of the water drawn into the plants through the roots is transpired with the remainder used in photosynthesis and cell growth.  The expiry of this much water through the leaves serves a cooling function both for the plant and humans in its vicinity.

Stiffening Agent

Water within the plant cells exerts an outward pressure (turgor pressure) which, like the air in a ballon, serves to give form to the non-wood parts of the plant pressure.  Turgidity is important in helping the plant compete for light energy as well as providing the force which pushes the roots through the soil.

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In vine growth and development, water is the ultimate multi-tasker.

©Wine -- Mise en abyme

Modern viticultural science made me do it (turn to Biodynamic viticulture that is)

Winemakers who are turning to biodynamic viticulture are not doing so just to be contrarians. Rather, they are being driven there by inexorable, wrong-track trends in traditional viticulture.  At least that is the perspective of Jason Tippetts as presented in the Spring 2012 issue of Gastronomica: The Journal of Food and Culture (The Science of Biodynamic Viticulture). This post examines Mr. Tippets' arguments.

As I have noted previously, quality grapes are a precursor of quality wine, and the science of viticulture has developed and evolved with a single goal in mind: the delivery of high-quality wine grapes to the cellar door.  The quality of wine grapes produced in a specific harvest is not only a function of that year's harvest conditions; it is also dependent on a combination of factors which, together, represent the full scope of viticultural science.

Mr. Tippetts takes issue  (based on his arguments) with my characterization of viticultural science as being quality-focused.  Rather, he sees the discipline as the problem.  In his view, there are two trends shaping the future of conventional viticulture: (i) a focus on the marketability of wine (which, over the long haul, will lead to mediocrity) and (ii) what I term the vineyard-imbalance cycle.  Let us examine these trends in turn.

The road to banality begins, according to Mr. Tippetts, while the viticulturist-in-training is still in school.  Deep dives into a broad array of science courses causes the budding viticulturist to "lose sight of what she loved about wine" and "why she thought it was important to be a winemaker in the first place."  The ideals and perspective of the fledgling has been hijacked and dulled by the weight and rigor of science.

The graduating student is a full-fledged agriculturist with no "insight into how winemaking might have significance beyond being a means of employment."  The graduate will be in possession of minimal amounts of inventiveness and innovation.  The scientific knowledge absorbed in the classroom will be unleashed against the problems (real or imagined) encountered in the vineyard.

The application of science-based, recipe-type solutions to vineyard problems has led to a "narrowing" of the focus of modern winemaking, according to Mr. Tippetts.  Rather than pursuing greatness in the bottle, winemakers are instead pursuing consistency.  Tippetts likens the viticulturist pursuing this path to a manufacturer who utilizes a set of raw materials and a well-established methodology to produce a consumer-friendly product.  "The potential greatness of the ends is neglected as a result of too much focus on the means."

Viticultural science, according to Mr. Tippetts, provides the basis for a continuing "unbalancing" of the vineyard environment; a cyclical, long-term degradation of the vineyard which almost guarantees reduced fruit quality.  This cycle was initiated when it was discovered that chemical fertilizers could improve the productivity of farmlands.  According to Mr. Tippett, fertilizers are salts and they cause the plants to take in more water, a situation which improves growth and productivity in the short term but saps the plant's energy, rendering it more susceptible to attack from parasites and other pests.  Pesticides are then applied to eradicate these pests (which they do until the pests adapt) but they also deplete the soil of its nutrients while also stressing the broader environment.

Viticulturists who are considering biodynamic viticulture want to make better wine, according to Mr. Tippets, and in order to accomplish that goal, they see the need to treat their vineyard differently. The implication here is that biodynamic viticulture is that path to better wines.

Looking at Mr. Tippetts' arguments, I give him credit for the implication throughout that wine is made in the vineyard.  It is a position that I hold.  Beyond that, however, I take issue with a number of his positions and assertions.  First, I thought that it was rather bold of Mr. Tippett to provide a blanket indictment of viticultural schools and practicing viticulturists as being co-conspirators in a plan to drive us all to banal wines.  He spent most of the article making the case against modern viticulture but was less-than-convincing in making a case for the biodynamic alternative.

Second, in some of his forays, he likened viticulturists to agriculturists, damning the latter practitioners with "faint" praise.  Third, Mr. Tippett asserts that viticulturist who want to make better wine realize that they have to treat their vineyards differently.  The implications here are that (i) only a subset of viticulturists want to make better wine and (ii) biodynamic viticulture is "the" vehicle for treating your vineyard differently (in so doing ignoring alternatives such as organic vitculture, for example).

I applaud Mr. Tippett for his advocacy of biodynamic viticulture but (i) he could have taken a more "pro"-active approach and (ii) his arguments do not necessarily point to biodynamic viticulture as the answer.


©Wine -- Mise en a byme

Grape vine nutrient requirements and acquisition

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 by the plant.  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 LGRGP.org and others

Soil is comprised of air, water, mineral particles (a mix of clay, silt, and sand), organic matter (decomposing plant material), and organisms (bacteria, algae, fungi, earthworms, insects, etc.).  Most of the solid soil matter is comprised of mineral particles while fully half of the overall content is pore space (in general a 50-50 mix of air and water).  Organic matter is: (i) critical in holding soil particles together; (ii) a reservoir of nutrients and water; and (ii) a food source for soil organisms.

Soil-based nutrients are resident either in the soil solution (water and dissolved minerals in the soil pores) or in the soil matrix (mineral particles and organic matter).  Two problems present themselves, however: (i) the concentration of nutrients in the soil solution is low and (ii) the nutrients that are resident in the soil matrix is immobile.  Plant roots have developed adaptions to allow growth into the soil matrix and capture of the nutrients needed for metabolic activity (Dr. Paul Schreiner, USDA-ARS) and we will discuss these later.

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.).

Roots have developed a number of physical and chemical adaptations to allow them access to an immobile nutrient set resident in the soil matrix (Dr. Schreiner).  The first adaptation is the root size and structure.  The vine plant deploys an always-growing, three-part root structure to meet its needs for anchoring, water- and nutrient-acquisition, nutrient storage during plant dormancy, and hormone production.  As it relates to nutrition, the plant deploys quick-growing, short-lived roots close to the surface to aid in moisture collection and primary roots for nutrient uptake (The woody roots (anchoring and transport) take up limited amounts of nutrients due to the presence of a waxy coating designed to keep ions in.).  According to UCDavis, about 60% of a vine plant's root structure is located within two feet of the surface but individual roots can grow as deep as 20 feet depending on soil permeability, water table levels, and rootstock variety.

Source: bccs.bristol.ac.uk

The second adaptation is the formation of symbiotic relationships with arbuscular mycorrhizal fungi (AMF), a non-specific fungi which extends its apparatus beyond the plant's zone of influence in order to retrieve minerals such as Phosphorous and Zinc and, in return, utilizes plant-derived carbon for its growth and reproduction.  Both the plant and fungi benefit from this relationship.

A third adaptation is the ability to secrete protons, organic acids, and enzymes and release these into the surrounding soil in order to increase the solubility -- and absorbability -- of certain ions.

In order to effect nutrient transfer, the roots of the plant has to be in direct contact with the soil matrix and the nutrients have to be delivered to the root surface.  Nutrients reach the root surface in a combination of three ways: interception, bulk flow, and diffusion.

Source: baileybio.com

Only a small fraction of the plant's nutrient needs are met by interception.  In this case, as the root grows into new areas, it displaces nutrients resident in the soil matrix.  Once on the root surface, the nutrients transit through the root's plasma membrane using available ion-selective channels.  The transfer is effected as the ions flow from areas of high concentration to areas of low concentration.

Bulk flow is the movement of nutrients towards the root as a result of transpiration water uptake.  Water enters a vineyard through precipitation or irrigation and that water either runs off, flows to levels beyond which it can be accessed by the vine plant, or remains in the rooting zone where it is available for the plant's use.  The plant uses water as an internal distribution vehicle (in addition to other functions) and facilitates this by expelling water through pores (stomata) in the leaves.  As water is transpired from the leaves, replacement water is drawn in at the roots.  This replacement water moves undiluted nutrients to the root surface but also carries dissolved nutrients into the roots as a part of its transit. Nitrogen is the nutrient most frequently acquired by the roots in this manner.

Source: talktalk.co.uk

Diffusion is the mechanism whereby nutrients move toward the roots as a result of agitation caused by the concentration gradient that develops near the root surface as a result of nutrient uptake.  Phosphorous and Calcium are the nutrients most susceptible to this type of capture.

In addition to the above mechanisms, as mentioned previously, the plant can utilize AMF to reach beyond its depletion zone in order to bring Phosphorous to the root interface.

While the above treats "naturally" occurring nutrients, the viticulturist will fertilize if he/she determines that a nutrient deficiency exists.  The nutrients added to the soil will make their way into the plant in exactly the same manner.


©Wine -- Mise en abyme

Macro-climates and their modifying agents

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.  That is not to say that these varieties cannot be grown outside of these environments; that is to say, however, that varietal typicity is compromised when these varieties are grown outside of their "zones."  In this post I will examine macro-climatic effects in greater detail and describe the agents which affect their impacts.

Macro-climate refers to climatic effects over large (hundreds to thousands of miles) geographic areas.  The table below shows a climate classification scheme based on the governing temperatures during the berry-growing season and examples of wine-growing regions that fall within the various climate bands.

Climate can also be described in terms of its "continentality", as shown in the table below.

Maritime climates 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.  This effect is not only limited to maritime areas, however, as regions that adjoin lakes and rivers will also be subject to similar effects. Franciacorta, for example, is moderated by winds blowing in off Lakes Iseo and Garde which protect the region from the autumnal and hibernial fogs that threaten from the Brescian Plains. Further, in the case of rivers, the water flow promotes air movement.  The downside associated with proximity to bodies of water is increased humidity levels and the risk of fungal diseases.

Offshore ocean currents can also have a moderating effect on a climate.  For example, the cool air blowing in from the Pacific Ocean mixes with the warmer air blowing in from the San Joaquin Valley creating an early morning fog in Napa's Oakville AVA.  This fog blows off by the middle of the day, allowing the grapes to gain the ripening benefit of the afternoon sun.  At the peak of the afternoon temperature, cooler air is once again funneled into the region from San Pablo Bay.  The Humboldt current off the coast of Chile serves much the same purpose for its regions, allowing grape growing in areas that would be otherwise too hot.

Mountains play a variety of roles in modifying a region's climate.  In the case of Alscae, the Vosges Mountains blocks the wine growing regions from the prevailing westerly winds but also provides a rain shadow effect which keeps most of the rainfall to the west side of the mountain and away from the vineyards. In the case of Oregon's Willamette Valley, climate is moderated by three openings in the Coast Range which provide gateways for the transit of cool air between the Pacific Ocean and the valley. The opening between Lincoln City on the coast and Salem in the valley is named Van Duzer Corridor. The remaining two (un-named) corridors run from Newport to Corvalis and Florence to Eugene, respectively.  Finally, temperature decreases by 33.08°F (0.6°C) every 328 feet (100 meters), thus allowing vineyards to be planted on mountain sides in areas where conditions would otherwise be uncooperative.

Forests can be the bane of vineyards in that they harbor birds but, as in the case of Bordeaux's Medoc, the forest to the west of the region serve as a barrier to the winds blowing in off the Bay of Biscay.

Vineyard selection and management practices can also work to blunt the effects of climate.  For example, by being on an appropriately sited slope, the vineyard can gain access to the sun's rays earlier and for longer periods of time thus aiding the ripening process in cooler climes.  A vineyard on a slope can also benefit from cold air moving downhill and being replaced by warmer air.  That zone of warmth can be hospitable for vine growth and berry ripening. 

Canopy management and trellising techniques could 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.

As it relates to the wine regions of the world, the ideal macro-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.  Grapes are, however, grown in a variety of areas which do not fit this profile, a situation made possible by a mix of natural events/edifices and human ingenuity.

©Wine -- Mise en abyme

Indigenous- versus inoculated-yeast fermentation: The pros and the cons

There is an ongoing battle between natural-wine proponents and pragmatists as to the types of yeast strains that provide the "best" results in the alcoholic fermentation of wine grapes, a battle, according to Isak Pretorius (The Power of Yeast, TONG #12) that is far from new.  According to Pretorius, once Louis Pasteur was able to show that some wild yeasts could spoil wine, the debate began as to whether pasteurization or the addition of sulphur dioxide should be utilized to kill off the spoilage agents or whether inoculated ferments should should be used in lieu of indigenous ferments.  This post looks at both sides of this continuing argument.

As described in a previous post, wine is the result of applying yeasts to grape berries/must/juice in an anerobic environment in order to convert the resident sugars into alcohol.  The yeast that receives most of the credit -- and does most of the work -- is a species called Saccharomyces cerevisiae (SC) which is "specialized in metabolizing media with high sugar content and small quantities of nitrogenous compounds" (Suárez-Lepe and A. Marota, New trends in yeast selection for winemaking, Trends in Food Science and Technology 23 (2012), 39-50.).  According to Fugelsang (Overview of yeast selection and malolactic fermentation on aroma, flavor and phenols), the yeasts (i) extract compounds from the solids in the must/juice in order to form the "characteristic metabolites of fermentation (alcohols, esters, fatty acids, carbonyls, etc.) and (ii) cleave cysteine-containing precursors such that volatile thiols (aroma component of several varieties) can be released.  SC is the yeast species which completes the alcoholic fermentation process in both inoculated and spontaneous ferments.

Grapes in a vineyard are hosts to what Gourrand (Using non-Saccharomyces yeasts during alcoholic fermentations: taking advantage of yeast biodiversity) calls native microflora -- molds, lactic bacteria, acetic bacteria, Saccharomyces spp, and non-Saccharomyces yeasts (Pichia, Metchnikowia, Kloeckera, Kluyveromyces, Candida, Zygosaccharomyces, Torulaspora, Cryptoccus, Brettanomyces, and Hanseniaspora) -- and it is the yeast element of this microflora that the feral-yeast winemaking adherents seek to exploit.  Wild yeasts accumulate on the grapes from flowering through harvest with the presence of SC being pegged at 1 in 1000 grapes (Robert Mortimer, Vineyard Theory of Wild Yeast, UC Berkeley).  At harvest, SC is the least prevalent of the grape-resident yeast strains.

In the case of indigenous (indigenous, wild, feral, and spontaneous used interchangeably throughout this post) yeast fermentation, the process is kick-started and dominated initially by the "weakly fermentative" -- but numerically dominant -- non-Saccharomyces Kloeckera.  This initiation can take up to a week to begin due to the relatively small amount of wild yeasts present at startup (relative to the amount of yeast used to begin the process in the case of inoculated ferments).  For the first few days of fermentation, the weakly fermentative non-SC population dominates but is then replaced by more adaptive non-SC strains.  As the alcohol level continues to rise, the more alcohol-tolerant SC increases in number at a rapid rate such that at the end of the fermentation it is the only species left standing.

Natural wine adherents assert that the progression from non-SC to SC fermentation in the vessel is an integral part of non-interventionist winemaking and adds complexity to the finished wine (Mortimer; Pretorius).  Critics of the approach see it as akin to Russian roulette because of the inherent risks (Ross; Pretorius): (i) the irregularity of natural fermentation and the associated risk of a stuck fermentation; (ii) in the event of rains around harvest time, the wild yeasts could be washed off the grapes; (iii) spoilage yeasts are often present in grape-derived yeasts; (iv) spontaneous ferments take longer to begin and longer to complete; and (v) while the positive characteristics of natural yeasts are not detectable after 6 or so months of aging, the negative characteristics tend to persist much longer.

For inoculated ferments, a large dose of SC is added to the juice/must in order to initiate fermentation.  The yeast strains utilized have traditionally been selected on the basis of the ability to start the fermentation quickly, the toleration of increasing alcohol levels, low acetic acid production, and resistance to sulfur dioxide (Ross; Suárez-Lepe and A. Marota).

As both Ross and Pretorius point out, the needs of large- and small-production wineries may lead to different emphasis in yeast-strain selection.  For the large producer, effective, efficient production and maintenance of quality is key and a strain that meets that need will be selected.  The smaller producer, on the other hand, is more likely to take advantage of varying yeast strains and temperature regimes as a means of enhancing the wine's aromatic and flavor characteristics.

To gain the benefits associated with both spontaneous and inoculated ferments, some winemakers are employing cocktails of strains hoping to get the "complexity of flavors ... without running the risk of contamination of spoilage yeasts" that comes along with the spontaneity.

According to Fugelsang, the first commercial yeast strain was introduced in 1965 by Red Star Yeast and, since that time, over 100 cultures have been commercially produced.  And winemakers continue to take advantage of these commercial strains in order to improve the capabilities of their wines. According to Suárez-Lepe and A. Marota and Pretorius, winemakers are continually on the lookout for yeast strains that can improve the technological and sensorial properties of their wines.

The advantages that are perceived by "inoculants" are clear: (i) quick, effective, efficient fermentations: (ii) flexibility; (iii) lower risk production process; (iv) the ability to tailor the fermentation; and (v) the ability to take advantage of future advancements in commercially produced strains.  The disadvantage of the use of inoculation is, as perceived by the "naturalists," even more power placed into the hands of the winemaker to manipulate the dickens out of the wine; and the customer loses as a result.

In a future post I will treat the topic of trends in yeast selection.

©Wine -- Mise en abyme

Oregon wine regions: The Willamette Valley AVA

My immediately preceding post provided an overview of winemaking in Oregon.  This post, the first of a series that will cover the individual winegrowing regions within the state, provides insight into one of its most important wine regions, the Willamette Valley.

The Willamette Valley AVA is the largest of the Oregon AVAs, covering, as it does, 5200 square miles to include an area from the Columbia River in the north to the Calapooya Mountains just south of Eugene and bordered on the west and east by the Coast and Cascade Ranges, respectively.  Named for the river that bisects its 60-mile width for most of its 150 mile length, the valley is home to two-thirds of the state's wineries.

Willamette Valley has a maritime climate -- cool, wet winters and warm, dry summers -- a climate pattern which, according to willamettevalleyagriculture.com, allows for a longer growing season.  The valley is protected by the Coast range to its west and a series of hill chains to the north.  According to oregonvineyardland.com, valley climate is moderated by three openings in the Coast Range which provide gateways for the transit of cool air between the Pacific Ocean and the valley.  The opening between Lincoln City on the coast and Salem in the valley is named Van Duzer Corridor.  The remaining two (un-named) corridors run from Newport to Corvalis and Florence to Eugene, respectively.

Rainfall averages 40-45 inches/year with 50% of the precipitation occurring between December and February and very little occurring during the summer.

As shown in the figure below, the Willamette Valley soil profile was established over a very long time horizon beginning with the hardening of ancient lava flows over 50 million years ago and continuing to the most recent layers deposited within the last 15,000 years.

Source: Pinot Camp 2012 document

According to the Oregon Pinot Camp 2012 documentation, ",,, great Willamette Valley Pinot Noir grows on rocky hillsides facing south or southeast, at least 200 feet above sea level and avoiding cooler hilltop microclimates over 800 feet."  The document goes on to assert that these conditions generally occur on volcanic, marine sedimentary, or windblown (loess) soils.

When it was initially designated in 1984, the Willamette Valley AVA extended over 3.3 million acres.  Over the intervening years, the valley's viticulturists have been able to discern and communicate the existence of six unique terroirs within the broader AVA and these six have all been designated as AVAs.  The characteristics of these AVAs are highlighted in the table  and figure below.

Source: Compiled from oregonwines.com

There are a total of 610 vineyards on the 15,120 planted acres in the Willamette Valley AVA and these vineyards produced 29,425 tons of grapes in 2011 (USDA NASS, Oregon Field Office, nassusda.gov).  Yield per harvested acre in 2011 was 2.18, indicating additional upside production potential without harm to the quality of the region's wines.  Of the 2011 wine grape production, 75.7% was Pinot Noir, 18.5% Pinot Gris and 5% Chardonnay.  Negligible amounts of Cabernet Sauvignon, Merlot, Syrah, and White Riesling are also planted.

Based on the numbers, Pinot Noir is king in the Willamette Valley. But there is no ubiquitous Pinot Noir profile.  According to Oregon Pinot Camp 2012, depending on the soil type, a different profile will emerge: on volcanic soils, Willamette Valley Pinot Noir will accentuate "high-toned aromatics, red/blue fruits, baking spices, and soft, succulent tannins;"  on sedimentary soils, "blue/black fruit, earth tones, and ... heavier tannins;" and on loess, "mixed berry fruits, exotic spices, licorice, cedar" along with briary components and round tannins.

With all of the assets listed above, Willamette Valley AVA would not have been as successful as it has become without the people.  From the pioneers, to the ones who followed, to the viticulturists and owners plying the trade today, the valley has been characterized by a cooperative, learning, working relationship which should serve as a model to every up-and-coming wine region.


©Wine -- Mise en abyme

Oregon wine industry: Current state and futures

Wine production in Oregon owes its existence to a band of hardy pioneers (Richard Sommer, David Lett, Charles Coury, Dick Erath) who ignored the conventional wisdom which held that the state was too wet and too cold to produce the quality of grapes required to make fine wine.  After over 40 years of grape growing and producing quality wines, the pathfinders, and those who followed closely behind, have conclusively refuted the arguments of the "soothsayers" and Oregon is now recognized as one of the world's leading cool-climate wine regions.  In this post I will examine the characteristics of Oregon as a winemaking region. The information provided is based on a telephone interview with Dr. Patricia Skinkis -- Viticulture Extension Specialist and Assistant Professor at Oregon State University (OSU) and member of the school's Oregon Wine Research Institute (OWRI) -- as well as a variety of secondary sources.

According to the USDA National Agricultural Statistics Service, Oregon 2011 wine grape production was 41,500 tons, a 33% increase over 2010 levels.  Production was distributed over a large number of grape varieties but Pinot Noir (23,726 tons) and Pinot Gris (6,046 tons) were by far the largest contributors.  The next leading varieties, contrastingly, were Chardonnay (1,923 tons), White Riesling (1,899 tons), and Syrah (1,319 tons).  Planted acreage in 2011 was 20,400 and, with average yield of 2.37 tons/acre, only Merlot, Muller-Thurgau, Sauvignon Blanc, Viognier, and White Riesling produce above the great-wine benchmark of 3 tons/acre.

With the exception of the regions shared with Washington and Idaho, the Oregon wine growing regions are concentrated in the valleys that lie between the Coast and the Casacade Ranges.  By functioning as a barrier to the warm, moist air flowing in from the Pacific Ocean, the Cascade divides the state into western (third of the state; heavy precipitation; moderate temperatures) and eastern (two-thirds of the state; low precipitation; more extreme temperatures) climatic zones.   

Source: Erath Winery

According to Dr. Skinkis, the climate in Oregon, while challenging in regards to grape growing, also has its benefits. The challenges include precipitation, limited days of sunshine placing the region at the edge of berry-ripening days, cooler temperatures, regular frosts in autumn, and large variation in weather from year to year rendering vineyard management tricky. The benefits include the moderating effect of the Pacific Ocean, clear definition of grape varieties that can be grown in each area, a good mix of cool-climate (in the north) and moderate-climate (in the south) varieties, long growing seasons, and full, but gradual, ripening of varieties.

According to Dr. Skinkis, the wine industry in Oregon is small (840 growers and 419 wineries) with the average grower working 20 acres of land.  Most of the businesses are family-owned, many as second careers.  In the cooler climate of the north, Pinot Noir, Pinot Gris, Riesling, and Chardonnay are the varieties of choice while the warmer southern climes gravitate to Cabernet Sauvignon, Merlot, and Syrah.  Pinot Noir (12,560 acres), Pinot Gris (2,590 acres), and Chardonnay (950 acres) represent the largest share of plantings in the state.  Overall, 63.6% of the grapes grown in the state are red varieties.

Dr. Skinkis sees a lot of interest in the industry in biodynamics but not many of the growers are Demeter-certified.  Instead a number can be classified as sustainable with LIVE as the most common certification and a large number of organic practictioners (The related panel at the Portland Wine Bloggers Conference lumped these viniviticultural practices together under a "sustainable" umbrella in that, according to the panel, they all focus on safety; safety of the workers in the vineyards, safety of the consumer, or safety of the environment.  The panel saw sustainable as poorly defined and the lowest standard as it allows the viticulturist to "ebb and flow" according to conditions.  Organic was more rigid but the certification of the grape versus the wine was viewed as very complex. Biodynamic was described as a self-nurturing universe.  Natural winemaking calls for a conscious decision to intervene as little as possible during the process. (See here for my post on natural wine.) LIVE (Low Input Viticulture and Enology) is wine-grape-specifc and, according to the panel, is more rigorous in looking at the system than either organic or biodynamic.  According to LIVE, 275 vineyards and 35 wineries in oregon are LIVE-certified.).

The industry works closely with OSUs OWRI (a Working Group of individuals who focus on wine-related issues) to address issues of concern.  The industry's focus today is on increasing fruit quality and improving yield, according to Dr. Skinkis, and she assists this effort by (i) providing new information and research and (ii) integrating applied research and Extension outreach for the benefit of winemakers, growers, and owners.  The areas of viticultural research that are currently being pursued are (Dr. Skinkis):

• Economic -- understanding the economic impact of different vineyard management practices
• Sustainability -- the economics and environmental effects of this approach and the role of cover crops in this area
• Yield management -- what level of fruit is the vine to ripen (Yield has become a measure of quality)?

Enological research is being pursued in the areas of microbial spoilage, color stabilization, and flavor and aroma compounds.

For the future, Dr. Skinkis envisions the research needs of the industry  pivoting to the following areas:

• Increasing the efficiency and effectiveness of managing grapes in a cold environment and the roles of nutrients and canopy management in that process
• How to better manage for vine balance (versus today's focus on yield management)
• New ways to manage troubled fermentations (Two potential paths are new yeast strains or a better understanding of native yeast strains.).

The work of a band of pioneers and the cooperative efforts of a second wave have served to lift the Oregon wine industry from a pooh-poohed concept to a strong, well-regarded presence on the world wine stage.  Using Burgundy as its north star, the industry has selected an industry structure and a variety mix that works perfectly for its geographic location as well as the persona of its practitioners.  The region's future remains ahead of it.

In future posts I will examine the Oregon AVAs in detail.


©Wine -- Mise en abyme