Tuesday, April 28, 2015

Characteristics of high-quality wine grapes

As the starting point for the production of a quality wine, it is imperative that high-quality grapes be delivered to the cellar door. I posit that high quality grapes are a funcntion of both what is within and what is without. Further, what is within can be divided into two broad classes: objective and subjective.

The objective criteria revolve around the components of grape juice at maturity, with soluble solids (major component being sugar), acid, and pH being the primary indicators based on (i) abundance and (ii) ease of measurement.
  • Soluble solids -- 6-carbon sugars (glucose and fructose; 90 - 95% of total), non-fermentable sugars (inclusive of 5-carbon pentose sugars), pectins, acids and their salts, tannins, pigments, and dry extract.
  • Acid – primarily tartaric acid (5 - 10 g/l in grapes) but also includes malic (2 - 4 g/l), citric, and other acids.
  • pH – measure of the amount of hydrogen ions in a solution. Regarded as the acidic strength of the solution.. Increases with increases in sugar concentration. According to Wynboer, not a reliable measure on its own. Should be between 3.1 and 3.3 for white grapes and 3.3 - 3.5 for red grapes.
  Table 1. Summary of objective grape quality measures (Source: UCDavis)
Wine Type
Soluble Solids (%)
Tartaric Acid (g/L)
18 - 20
7 - 9
2.8 – 3.2
White Table
19 - 23
7 - 8
3 – 3.3
Red Table
20 - 25
6 – 7.5
3.2 – 3.4
Sweet Table
22 - 25
6.5 - 8
3.2 – 3.4
23 - 26
5 – 7.5
3.3 – 3.7

Soluble solids are reported in Brix, specific gravity, Baume, or Oeschle, depending on preferences, and are measured by refractometry (juice in the vineyard) or hydrometry (during fermentation). Anthocyanin and total phenolic levels are measured using Near-infrared and Spectrophotometry, equipment that is not readily available to most wineries. Titratable acidity (TA) is measured by acid-base titrations while pH is measured using a pH meter.

It should be noted that, depending on winemaker preferences or climatic conditions, some of the soluble solids and acidity level metrics may be over- or under-shot and is then adjusted during the winemaking process by acid/sugar addition or subtraction.

The subjective criteria for quality are as follows: color; ease of removal of berries from pedicel; texture; aroma; and flavor. These tests should be conducted by the winemaker during vineyard walk-throughs. Of the objective tests mentioned, the test for flavor is the most important. Bisson (UCDavis) sees optimal maturity as assessable only by monitoring flavorants themselves but such a task is laborious and expensive and has to be approximated through tasting.

But all of the quality elements associated with the grape are not subcutaneous. 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). According to Loureiro and Malfeito-Ferreira (Spoilage yeasts in the wine industry, International Journal of Food Microbiology 86, 2003), mature, healthy grapes harbor microbial populations at levels of 103 - 105 CFU/g (colony forming unit -- a measure used in microbiology that indicates the number of micro-organisms present in a water sample (www.legionella.com/cfu)), levels that vary based on environmental conditions (rainfall, temperature, grape variety, the application of chemicals in the vineyard).

It is the yeast element of this microflora that natural-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.

Wine-associated yeasts are identified in the table below.

©Wine -- Mise en abyme

Thursday, April 23, 2015

Penfolds and the Pinnacle of Australian Wine: A Pebble Beach Food and Wine tasting panel

I love to participate in tastings where Paolo Basso is lead because, not only is he a pure taster, he is also elegant, clear, and precise in describing the sensory characteristices of the wine "under the microscope." But I also love participating in tastings led by DLynn Proctor because he is unmatched in describing the technical characteristics of the wine and the conditions under which it was produced; a style in marked contrast to the Basso approach. DLynn recently headlined a panel at Pebble Beach Food and Wine (April 9 - 12, 2015) titled Penfolds and the Pinnacle of Australian Wine and I report on that tasting in this post.

The tasting was scheduled to be held at 3:30 pm on April 10th in the St Andrews East Room at The Inn at Spanish Bay. I had driven around in the town of Monterey for a bit after picking my car up at the San Jose Airport and, after a brief lunch, headed north on Lighthouse Avenue and then southwest on David Avenue before making a right into Congress Road and into the grounds of The Inn.

The overall setting at The Inn is one of elegance, both outside and in, and conversations seemed to be conducted in hushed tones. No drunken throngs here. I inquired after the St Andrews Room and made my way there and mingled with the other attendees awaiting entry and the start of the tasting. The room, once the doors were opened, was rather expansive and was occupied by rows of tablecloth-bedecked tables oriented towards a raised platform at the front. The platform was occupied by a table and four chairs and would be the home of the panelists for the duration of the event.

After some additional socializing within the room, the meeting was called to order and DLynn introduced the panel members. In addition to himself, they were:
  • Greg Harrington MS, Founder and Winemaker, Gramercy Cellars
  • Ray Isle, Executive Wine Editor, Food & Wine
  • Kim Beto, Vice President of Key Accounts, Southern Wine and Spirits of Northern California.

Once the introductions were out of the way, DLynn gave a brief overview of the history of Penfolds. My notes regarding this particular discourse was "He understands and disseminates the story of Penfolds like no other ..." A little bit of that Penfolds history (with a Grange bent) can be found here.

The tasting was divided into non-Grange and Grange flights, the former consisting of six bottles and the latter of five. The non-Grange labels, drawn from the Penfolds Collection, were RWT, Magill Estate, and St. Henri. Of the three, I had only previously tasted the RWT. The defining characteristics of the three non-Grange labels are presented below. Similar data for Grange can be found here.

Initial Vintage
Fruit Source(s)
Barossa Valley, South Australia
Stainless Steel (SS) tanks with wax-lined wooden header boards; finished in barrels
12 – 15 months in 50 – 70% new French oak hogsheads (300L)
Magill Estate Shiraz
Magill Estate, Adelaide. Single-vineyard blocks to include Blocks 1, 2, and 3
Wax-lined, open concrete fermenters with wooden header boards; after basket pressing, components complete fermentation in barrels
12 – 15 months in 65% new French and 35% new American oak hogsheads
St Henri
1953 – 1956 experimental; commercial in 1957
Cabernet Sauvignon; Shiraz
CS from Coonawarra and Barossa Valley; Shiraz from Barossa Valley, Eden Valley, Clare Valley, McLaren Vale, Langhorne Creek, Robe, and Bordertown
Stainless Steel (SS) tanks with wax-lined wooden header boards; finished in barrels; somer componenets vinified at Magill Estate
18 months in large (1400L), old oak vats

The first tastings within the non-Grange flight were of the 1998 and 2009 St. Henris. According to DLynn, St. Henri predates Grange and was actually purchased by Penfolds in the 1940s. During the 1950s and 1960s, the label rivaled Grange.

According to DLynn, these wines were double-decanted 1 hour before the tasting. The 1998 exhibited notes of spice, leather, tobacco, smoked meat, burnt toffee, chocolate, and mint. On the palate a savoriness and surprising youth. Intense, bright, some salinity, spiciness, and slightly grippy tannins. Long, spicy finish. According to DLynn, 2.4% Cabernet Sauvignon included. The nose on the 2009 was unyielding. Slight vegetality. Weighty on the palate with a great core of fruit. Intense. Eucalyptus notes. It is not as structured as the 1998 but a beautiful wine nonetheless.

The 1997 RWT had a layered complexity with a perfumed nose and accompanying notes of eucalyptus, mint, earth, spice, and dried tree bark. Delivers on the palate but not on the promise of the nose. Rich and powerful with blackberry, cedar, and truffles dominant. Long, drying finish. The 2012 RWT had a core of blackberry fruit supporting notes of dark chocolate, soy, and mahagony. Concentrated fruit on the palate along with a saline character. Balanced by appropriate tannin structure and acidity. Lengthy finish.

Magill Estate is a 5.1 ha property and is, according to DLynn, the spiritual home of Penfolds. The wine is 100% Shiraz and the 2004 exhibited notes of green bark, coconut, petrol, smoke, charcoal, and toffee along with a hint of phenolics. On the palate elegant and balanced with a drying finish. The 2012 was more "in your face" than was the 2004. Same nose as for the 2004 but with more intensity. Dark fruits and brightness on the palate.

The Grange flight consisted of wines from the 1986, 1989, 1998, 2008, and 2010 vintages. I had tasted the 1986 as a part of our Five Decades of Penfolds Grange tasting and had described it as having aromas of dill, bay leaf, thyme, phenolics and a little greenness. I had also described it as balanced and savory and having integrated tannins and a long finish. Similar characteristics exhibited at this tasting except for a hint of portiness taht I had not evidenced previously.

The 1989 wine had also been tasted earlier and in that case I described it as having ripe fruit, molasses, savoriness, beef broth with dark fruit and molasses on the palate. The notes for this tasting aligned somewhat in that I evidenced an aromatic high tone along with pyrazine, sugar cane, and molasses on the nose to go along with dark fruit, pyrazine, and molasses on the palate.

The 1998 had rich, dark, ripe fruit along with baking spices and pepper on the nose. Palate-filling. Rich and concentrated with a long creamy finish. Hint of port.

The 2008 was perfumed on the nose with baby talcum powder, sawdust, chocolate dust, and cocoa dust. Elegant on the palate with sweet ripe fruit and a hint of green. Toffee, coffee, chocolate, and a long smooth finish.

The 2010 also exhibited an elegant nose. On the palate thick, rich dark fruit. As Yogi Berra would say, "Its future ahead of it."

All in all this was a fun tasting. Dlynn and Greg made stellar contributions to the affair with DLynn being "always on" and Greg having taken the necessary steps to be prepared for the event. I wish that the audience member who sucked up most of the oxygen had been a little more knowledgeable.

©Wine -- Mise en abyme

Thursday, April 9, 2015

The Châteauneuf-du-Pape AOC

The Châteauneuf-du-Pape AOC is known for "rich red wines redolent of the heat and herbs of the south" and "full aromatic white wines with a crisp freshness," with both styles complexed by blending; up to 13 varieties for the reds and five for the whites. I was pleased to be invited by the Fédération des Syndicats de Producteurs Châteauneuf-du-Pape to explore the region and its wines as part of a 2014 Digital Wine Communications Conference pre-conference Press Trip. The trip itinerary is presented below.

Meals and Tastings
Terroir of Chateauneuf-du-Pape with geologist Georges Truc (treated previously)
Lunch at La Mère Germaine with a tasting of CdP whites
Domaine La Barroche
Dinner at La Table de Sorgue and tasting of older CdP vintages
Domaine de Nalys

Chateau Fortier

Ogier – Clos de l’Oratoire

It is from this visit, plus subsequent secondary research, that I have crafted this description of the Châteauneuf-du-Pape AOC.

The Châteauneuf-du-Pape AOC, the largest and most important of the Southern Rhone AOCs, is located in the westernmost portion of the Vauclause region, 19 km north of Avignon and 10 km south of Orange. Its 3200 ha of vineyards renders it the largest appellation in the Southern Rhone (and almost equal to the size of the entire Northern Rhone, which comes in at 3264 ha) and its annual production surpasses the total of all of the Northern Rhone appellations.

The appellation is distributed over five communes and 134 lieux-dits.

Size (ha)
# of Lieux-dits
Percent of Lieux-dits

The appellation's climate is Mediterranean with approximately 2800 hours of sunshine and 650 mm of rain annually. The mistral, a strong, cold, dry wind from the north or mortheast, is a striking feature of the environment. It blows annually for approximately 120 days per year, primarily in the spring and winter. It is advantageous, viticulturally speaking, in that it (i) prevents fungus growth in the vineyards, (ii) rapidly dissipates water from grapes after rainfall, and (iii) protects against late spring frosts. However, it also dries out the soils and can do physical damage to young, unprotected vines.

There is a growing trend in Châteauneuf-du-Pape away from traditional viticulture and towards more sustainable approaches. Many of the vineyards are either organic or biodynamic, or are in the process of converting to one or the other. Syrah vines are trained Guyot while all other varieties are either gobelet or bilateral cordon de royat. Vineyard plantings of the various varieties are as shown below.

Size (ha)
Grenache Noir








Terret Noir

Red Total
Grenache Blanc




Clairette Rosé

Picpoul Blanc


Grenache Gris

White Total
Source: Karis, The Chateauneuf-du-Pape Wine Book

The generalized Chateauneuf-du-Pape winemaking process for red wines is illustrated below.

©Wine -- Mise en abyme

Thursday, April 2, 2015

Landscape formation and the soils of Chateauneuf-du-Pape

The iconic view of Chateauneuf-du-Pape (CdP) is of gnarled vines rising out of a landscape comprised of smooth, rounded stones; stones, we are told, that aid in the ripening of grapes by capturing heat during the day and releasing it back into the environment at night.

I have always wanted to hold some of these stones in my hand and got the opportunity back in October of 2014 when I was honored to be among a group of bloggers invited by the Fédération des Syndicats de Producteurs Chateauneuf-du-Pape et Tavel to visit the region as part of a DWCC 2014 pre-Conference trip. The trip included one day in Tavel and one day in Chateauneuf-du-Pape and one of the highlights was the two hours spent in the CdP vineyards with geologist Georges Truc.

Today's post presents my understanding of the landscape formation and current soil conditions in Cdp and is based on the presentation of M. Truc as well as research conducted subsequent to the visit.

Geologist George Truc with KelleyMcAuliffe in background

In attempting to build a view of the formative influences on CdP, I have previously posted on the geology of the Rhone Valley as well as the landscape of the Northern Rhone sub-region. The Southern Rhone can itself be divided into two geologic spaces comprised of the Cotes-du-Rhone appellations and the communal appellations. While focused on CdP, a lot of the geologic effects are similar for areas such as Lirac and Tavel, for example, and can stretch as far east as Gigondas.

At the beginning of the Miocene (about 24 million years ago), the area that now constitutes the AOCs of CdP, Tavel, and Lirac were a part of the Urgonian limestone peaks of which modern-day Plateau du bois de Saint Victor, and the series of limestone buttes that are visible as you approach CdP, are a part. The portions of the limestone peaks between Lirrac-Tavel and Gigondas were submerged by the Miocene and Pliocene seas and overlain by sandy molasse and sand as a result (Fanet, Great Wine Terroirs).

The uplifting of the Alps displaced a lot of material which the Rhone carried down into the areas identified in the foregoing. Successive glacial periods resulted in the Rhone down-cutting into the existing landscape leaving stony terraces at different heights, with each terrace being named after the glacial period in which it was formed. The major CdP landscape-formative occurrences are tabulated below.

Early Tertiary Period
(66 - 37 My)
  • Limestone rock peaks emerged from the vast plain
  • Saint-Genies Mountain and Lampourdier Hill, remains of the coral reef that bordered Vocotian Sea
Miocene and Pliocene
(24 - 2 My)
  • Mediterranean Sea floods the Rhone Valley on two occasions
  • At max height covers all land masses except Saint-Genies Mountain
  • Thick layers of marl and sand laid down on sea floor
(5 - 2 My)
  • Considerable erosion in Alps
  • Rhone and tributaries carry vast amounts of fine and coarse gravel down stream
  • As river varies its course from west to east, a thick layer of gravel and stone covers the Miocene sands
Early Quaternary
(2 - 1 My)
Temperature drop in the glacial Riss stage
  • Seawater transformed into glaciers
  • Sea levels drop, encouraging the down-cutting of the Rhone through the Miocene sands
Late Quatenary
(1 - 0 My)
Glacial phase in two stages
  • Excavation due to cooling
  • Aggradations of large rounded pebbles due to warming
  • Limestone massifs prevent clearing of downstream deposits
Present Day
Fine alluvial soil deposited on the riverbed and surrounding plain

MY = Millions of years. Data sourced from Karis, The Chateauneuf du Pape Wine Book.

In his discussion about the soils, M. Truc indicated that there were three principal soil types in CdP and we drove to each of these in order to observe and be provided with the appropriate background. The first soil type that we drove to was on the east side of CdP and was described by  M. Truc as calcaire (limestone), that had been laid down in the Cretaceous period (145 - 66 million yeras ago). The limestone here is eroded and is the same age as the limestone encountered in Tavel. This soil is, according to M. Truc, best suited for whites as it imparts a salinity and minerality. It is not as well suited for reds as the tannins are not that evident and they do not realize the same power as the other terroirs.

The vines try to grow through cracks in the limestone, some of which (the cracks, that is) are filled with clay minerals. There are clay-based soils below the limestone. Clay is a very important part of any winemaking soil in France as it is key to provision of mineral to the vines

In describing the soils of the high terraces, M. Truc indicated that they were made from quartzite and had been deposited by the Rhone around 1.8 million years ago during the Quaternary period. Below the stones there are a variety of soils. Granite and gneiss were the original deposits in the Rhone region but extreme weathering dissolved the limestone and destroyed the granite leaving only quartz. Silica and feldspar was liberated from the quartz and formed clay. In the upper layers it manifests as brown soil. If you go further, it becomes red soil, and, even further, black mica.

The stones drain water and extends the heat of the day into the night. Powerful wines are produced from vines grown on these stony soils. Here vines are planted at between 2500 and 4000 vines per ha.

Most of the limestone in CdP has been covered by sand or clay with the most sandy region being to the east and being a product of the Miocene era. According to M. Truc, a lot of the sand is as a result of deposition of erosion from the Alps. Sandy soils had not been considered a good winemaking terroir untill recently but is now home to some of the finest, most elegant wines as, according to M. Truc, evidenced by the wines of Chateau Rayas and Clos du Caillou.

The map shown above has been modified to align the descriptors with the soils map shown earlier.

A description of the CdP wine region will be presented in a later post.

©Wine -- Mise en abyme