Oakville AVA, the heart of the broader Napa Valley AVA

Oakville, one of Napa Valley's renowned AVAs, is located in the heart of Napa between Rutherford AVA to the north and Yountville AVA to its south.  Named after the dense grove of dark-green canyon oaks that are synonymous with the area, Oakville was launched as a wine-growing region with the 1868 purchase of a 240-acre plot by one Henry Walker Crabb who immediately planted said plot to vine.  The resulting vineyard was called To Kalon, Greek for "the call of beauty."  The AVA -- status granted in 1993 -- runs north to south between Rutherford and Yountville and up 600 feet in the Vaca Mountains to the east and Mayacamas Mountains to the west.

The Oakville climate is Mediterranean-like thanks to the interaction of the cool air blowing in off the San Francisco Bay and the warmer air from the San Joaquin Valley.  Oakville is located such that it receives daily doses of early morning fog from San Pablo Bay to its south.  This morning fog blows off by the middle of the day allowing the grapes to gain the ripening benefit of the Napa afternoon sun.  At the peak of the afternoon temperature, cooler air is once again funneled into the region from the San Pablo Bay.  The afternoon sun promotes full grape ripening while the cooler air in the mornings and late afternoon preserves the acidity which is critical for wine balance.

Rainfall in Oakville amounts to 35 inches per year, falling mostly in the winter and early spring.

The soil in Oakville is comprised, for the most part, of decomposed rock that has been carried downhill from the mountains and has been intermixed with the sand, clay, and gravel deposits of the Napa River flood plain.  This soil has excellent water drainage capability and rooting depths in excess of 100 feet.

To the west, a collection of rock types known as the Franciscan formation underlie two large alluvial fans comprised of clay and bale loams.  A slope of 2 degrees from the foothills to the Napa River plain allows excess rainfall to flow downslope into the river.  On the eastern side of the valley there are some instances of Franciscan formations and smaller alluvial fans but the dominant influence is that of the volcanic composition of the Vaca Mountains as exhibited in exposed volcanic tuff and evidence of lava and pyroclastic flows.

There are 5000 acres of vineyard in Oakville planted to varieties such as Cabernet Sauvignon, Merlot, Cabernet Franc, Zinfandel, Chardonnay, and Sauvignon Blanc. Seventy-five percent of the grapes grown in Oakville is Cabernet Sauvignon which, along with Merlot, Zinfandel, and Cabernet Franc, thrive on the geological formation known as the Western Bench (above the floor of the valley at the base of the Mayacamas Mountains).  Chardonnay and Sauvignon Blanc do well on the clay and sandy loans of the valley floor.

The wines of the Oakville AVA are deep and richly flavored with the Cabernet Sauvignon being especially opulent.  The wines have a better balance of sugar and acidity than neighboring AVAs because the grapes ripen at a more controlled pace.  Cabernet Sauvignon grown in the Benchland portion of the AVA is thought to be less herbaceous and minty than its non-Bench counterparts as well as being fuller-bodied and longer-lived.

Notable producers in this AVA include Opus One, Robert Mondavi, Heitz Cellars, Groth, Silver Oak, Turnbull, Screaming Eagle, Dalle Valle, Far Niente, Harlan, and PlumpJack.


© Wine -- Mise en abyme

The science of viticulture: Soils and vineyard site selection

The vineyard site is a key variable in the production of high-quality grapes, which is, itself, a key requirement for the production of high-quality wine.  In the absence of an existing vineyard, the viticulturist has to seek out a site on which the wine grapes will be planted.  I have detailed the climatological and topographic requirements for such a vineyard in recent posts and will devote this instance to soils, the final -- and second only to climate -- site-selection requirement.

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 -- Dictionary.com) 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.

Adequate amounts of the appropriate nutrients are required to support proper growth of the vine, fruit development, and fruit maturity.  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

The key factors in nutrient availability are soil type, soil composition, and root structure.  Soil type dictates the quality of nutrients present and the adequacy of water drainage.  The soil-type page shows the different types of soil that are of interest to the viticulturist.  The optimal soil type 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.).  Soil composition affects root growth and development and the availability of nutrients for soil uptake.  The roots of the vine plant, among other things, absorb water and nutrients and store the nutrients that nourish the plant during dormancy.  The principal roots of the plant are tasked with nutrient delivery and storage.

By this time the viticulturist will have been exposed to enough information to select a vineyard site which will have a better than even chance of producing high-quality grapes.  All of the pertinent questions about climate, aspect, slope, elevation, and soils have been raised and a path to high quality has been carved out.  The next task will be setting up the vineyard on the selected site.

© Wine -- Mise en abyme

Summer of Riesling comes to Florida

You would think that Riesling (forgetting its complexity for the moment, and the fact that it is the Master Sommelier's drink of choice) would be perfect for Florida: light and refreshing (at the less-sweet end of the spectrum) and the ability to pair well with the diverse cuisines that are characteristic of the state.  But that is not the case.  Riesling does not do very well here.

The distributors in the state want to turn that around and have banded together (a feat in and of itself) to change the perception and acceptability of Riesling and are using the Summer of Riesling campaign as a vehicle for this awareness-raising effort.  The Summer of Riesling is the brainchild of New York Sommelier ( and self-proclaimed acid hound) Paul Grieco and is intended to "showcase the German grape in all its geographic and stylistic diversity."

The Summer of Riesling efforts in New York have both a retailer and a consumer component.  The Florida initial effort is aimed at retailers, hoping that by influencing their actions more Riesling will make its way into the hands of the consumer.  The Florida effort is being kicked off with a promotion titled Summer of Riesling Roadshow which has a number of distributors showing their Riesling wares to wine buyers/owners of restaurants, wine bars, and wine shops.  It is hoped that these establishments will commit to pouring three Rieslings by the glass for the entire 94 days of summer.  The incentive? T-shirts, buttons, stickers, etc.

The Roadshow was kicked off with a tasting yesterday at Citrus Restaurant in Orlando.  Distributors at the event included Stacole Fine Wines, Selected Brands, Tout Petit Vin, Premier Beverage, VineCraft, Domaine Select, SWS, and Loosen Bros USA.  The event was well attended as a steady stream of visitors flowed through in the scheduled three-hour tasting.  In my conversations with them, the distributors seemed very earnest about the endeavor.  The individuals manning the tables were all enthusiastic boosters of Riesling and expressed the hope that this would be the launch of a resurgence of Riesling sales in the state.

The Roadshow will continue with tastings in Tampa today and then in West Palm Beach and Miami next week. Wishing them the best.

© Wine -- Mise en abyme

A wine-dinner at Chatham's: Guest post by Ron Siegel

A group of seven wine friends decided to get together at the last minute for an impromptu dinner at Chatham’s Place ( a Gayot-described “longtime neighborhood ‘it’ spot serving continental fare” and “a delightful detour from the glitz of nearby Restaurant Row”) last Thursday night.  This is a place that I used to frequent but had forgotten about and so had not graced its doors for a number of years.  The food was well prepared and the  wine service was outstanding. The restaurant was quite busy for a Thursday night and more than met the expectations set by the recommendations from @winORL and @thewinebarns.

We had recently experienced a lackluster wine performance at the Chef’s Table at Victoria and Albert’s and so were anxious to get back into the “wine saddle.”  The wines were scintillating (with one exception) and wiped the V&A experience from our mind as quickly as a hole-in-one causes a bad golfer to forget the triple bogey he/she had on the prior hole.

We started with a very nice Champagne -- Mailly Gabriel Simon Cuvée Montesquieu Grand Cru NV -- which had a slight oxidative note (a characteristic that I love in Champagne) along with some citrus, toasted bread, a nice acidity and a medium finish.  I made a note to buy some of this wine thinking that it would be a nice grower Champagne to own but saw that it retails for over $100.

The whites on offer were a 2005 Meyret-Gachet Chateau-Grillet (100% Viogner monopole) and a 1999 Raveneau Butteaux.  We opted to taste these wines simultaneously for comparison purposes.  Unfortunately the Raveneau was corked (Bummer in that it was my offering).  The Chateau Grillet exhibited floral and citrus notes with stones, seashell, and Beeswax on the palette. 

Next up was another one of my offerings, 1947 Pierre André Chambolle-Musigny.  Wow! Massive red fruits, very sweet, ripe with great acidity. A touch of tomato and protein. @wineORL thought this was all about the acid. This wine showed much younger than its age.

The 1996 Rinaldi Brunate Lecoste Barolo showed red fruits and cotton candy.  It was very floral with dusty tannins. It will become an even finer Barolo with more time in the cellar.

The Berardenga Rancia Reserva Chianti 1995 was poured from a 3-liter bottle.  Nose of cherry, licorice, tobacco and spice. My only complaint was that the finish seemed light and lacked complexity. Maybe it needed more time to open up.

The 1999 Chapoutier L'Ermite and 1990 Les Cailloux Cuvée Centenaire  were opened and tasted together.  The Chapoutier had a nose of blueberry, roasted nuts, pepper, and herbs.  Meaty with a shoe polish finish. These wines will age effortlessly for 50 + years.  I had high hopes for the Les Cailloux (another one of my contributions) based on its Parker score (100) and it delivered. Very sweet and opulent Kirsch fruit. Almost burgundian but more rustic with soy, balsamic, iron, and beef blood in the mouth. I love CdP and this was a great one!

Gruaud Larose 1990 and Gruaud Larose 1982 tasted comparatively.  The 1990 exhibited camphor, gun powder,graphite, smoke and some earth. I liked this but it could not compete with the 1982 tonight. It still needs time and may have benefitted with a decant.  The 1982 showed sweet black fruits with spice, cigar box.  Great aromatics with some barnyard and earth. This wine was reminiscient of the smell and taste of the 1966 La Mission Haut-Brion but was fresher. I feel this is the best vintage of Larose since the 61 and would love to do these side by side.

The Chateau Margaux 1983 bottle looked brand new with a very high fill. This was the best 1983 Margaux that I have had in some time as it was much cleaner and showed less damp earth than my most recent three. Nose of black fruits with camphor, vanilla, truffle and floral notes. Very silky tannins and long finish.  A more masculine vintage for Margaux.

The Pichon Lalande 1986  had a nose of black fruits, cedar,lead pencil, steely.   Classic Pauillac with firm tannins and good acid.

The 1995 Lynch Bages was still very young and tight as are most 95's.  I love Lynch but this just wasn't showing a lot tonight.

Dana Estates Helms Vineyard 2007 was next up.  This was another one of my contributions. Dana was the highest-priced barrel ($70,000 for a 5-case lot) at the recently concluded Premier  Raspberry nose with toasted oak, rich, ripe fruits.  Nice balance between the fruit and tannins. Very opulent and rich. No one would confuse this with an old world wine.

We finished with a 1975 Sauterne that everyone seemed to enjoy.

All in all a great night of food and wine with good friends.  Unfortunately, getting home after 2:30 am on a Friday morning was no fun with my alarm going off at 6:45 am later that day.

© Wine -- Mise en abyme

The science of viticulture: Topography and site selection

Selecting the "right" site for a new vineyard is a key requirement for the eventual delivery of high-quality wine grapes to the winemaker.  The climatic requirements for this vineyard (discussed previously) 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.
The physical characteristics of a potential site can serve to enhance/retard climate effects while also serving, in their own right, to meet specific needs of the grapevine.  These physical characteristics -- often referred to as topography -- are elevation, slope, and aspect.  Each will be discussed in turn in this post.

Elevation

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 would allow 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

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.

As shown below, the effects of slope can be ameliorated by terracing, an expensive proposition both in terms of establishment and maintenance.

Aspect

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.  At Quinto do Vesuvio in the Douro, for example, the slopes are primarily north-facing, allowing the grapes, according to company President Paul Symington, to benefit from the luminosity of the sun without having to deal with the long, direct sunlight (in Douro heat) associated with south-facing slopes.

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.

These, then, are the topographical issues that the viticulturist has to consider when selecting a site for a new vineyard.  We will address the soil issues in site selection in the next post.

© Wine -- Mise en abyme

You are here: A roadmap for a wine-quality journey

Sometime in January of this year I wrote a post on balance as a measure of wine quality and, upon its completion, I realized that I had not previously defined wine quality, a situation which I sought to address with two subsequent posts.  Since that time the wine quality posts have taken on a life of their own and I have brought you, the reader, along on the ride.  You may be reassured to know that I do have a map (several, to be candid) and so I wanted to take the opportunity to show you from whence we came and where this trip will be going.  I did begin writing about quality before I had developed a proposed quality framework but we will make-believe that that was not the case and that the framework preceded any writing on the topic.  The framework that I proposed is shown below.

The broader conceptual quality arguments have been addressed in two posts to date:

• A framework for the assessment of wine quality: Defining the space
• Development of a framework for the assessment of wine quality

At the elemental level of the framework I have begun working on the intrinsic (in-the-glass) quality factors:

Palate

• Wine balance as a quality measure
• The role of acidity in wine balance
• The role of alcohol in wine balance
• Ameliorating alcohol-induced wine imbalance
• The role of tannins in wine balance
• Available mechanisms for ameliorating tannin-associated wine imbalance

Appearance

• Appearance as an indicator of wine quality

Nose

• Flavornet: A comprehensive source of wine odor descriptors
• Odor as an indicator of wine quality: Mapping the sources

In order to determine the role of odor in wine quality, I decided that I needed to track down each and every source of the odors that end up in a wine glass in order to understand each source's contribution.  The map of the sources is represented in the graphic below and is another layer of detail beneath the original wine quality framework. You know. Mise en abyme.

I decided to begin with the aroma contributors that were specific to the grape and this yielded yet another framework -- the elements of viticultural science -- which is itself reproduced below.

One post has been written to date against this framework:

• The science of viticulture: Climate and site selection

So you see.  You are here.  I will complete the elements of viticultural science, then the odor sources, and then get back to the completing our discourse on intrinsic wine quality.

Good luck.

© Wine -- Mise en abyme

The science of viticulture: Climate and site selection

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 winery.  The quality of wine grapes produced in a specific harvest is not only a function of that year's harvest conditions.  Rather, it is the result of a combination of factors which, together, represent the full scope of viticultural science.  I will cover most of the inherent elements of viticultural science in a series of posts as a part of my investigation of the source of grape-derived odors.

There are three major areas of concern for the viticulturist as he/she sets about the task of delivering quality grapes to the winery door: (i) selecting the site which will best ensure goal attainment; (ii) setting up the vineyard with the appropriate elements such that cost-effective goal-attainment is promoted; and (iii) implementing a cost-effective, repeatable vineyard management regime which is reflective of the operating conditions.  Within these major considerations there are a number of sub-elements where the rubber really meets the road and I will focus our coverage of the topic on these areas beginning with today's writeup on climatic considerations in site selection.

The site selected for a new vineyard will determine the amount and quality of fruit produced, the resources required to manage the vineyard, and, ultimately, the profitability of the vineyard.  Selecting a site for a new vineyard is generally a compromise between a number of factors.  For example, most of the exceptional vineyard sites in the world have been under vine for many a year, leaving less-than-perfect options available for the aspiring vineyard owner.  Second, most prospective vineyard owners are drawn to sites that are readily accessible to them and this limiting facor comes with a given climate.  And so on.  Site selection is thus the process of making an optimal choice within the bounds provided bythe needs of the wine grapes, the available site options, and associated limiting factors. 

Source: Compiled from arcserver2.iagt.org

The key site-selection factors for consideration are climate and site physical characteristics.  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.  For example, Syrah appears to flourish in warm climates while Riesling does best in cold.  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."

As it relates to the wine regions of the world, the ideal climates for vitis vinifera are Mediterranean and marine west-coast climates which are both 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.

Source:www.buywineonline.co.uk

In viticulture, three separate aspects of climate are normally considered: macro-climate, meso-climate, and micro-climate.  Macro-climate refers to climatic effects over large (hundreds to thousands of miles) geographic areas and are either continental or the aforementioned maritime.  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.

Meso-climate covers a much smaller area than does macro-climate and is generally the scale at which site decisions are made.  It is at this level that that the physical aspects of the surroundings -- elevation, slope, aspect -- can temper broader macro-climatic effects.  The climatic effects of these physical elements will be covered when they are discussed individually.

Micro-climate are the conditions that exist in the vineyard from the soil upward into the vine canopy and, as such, is more relevant when the land is under vine than in the site-selection phase.

One of the key grape needs is adequate sunlight and heat to allow both the fruit and the vegetative aspects of the plant to mature.  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 the site-selection dialogue.

Source: Compiled from oregonviticulture.net

These then are the broader climatic considerations for the viticulturist in selecting a site for a new vineyard for the production of quality wine grapes.  The physical characteristics that should be evaluated will be covered in the next post on viticultural science.


© Wine -- Mise en abyme