Vol.18, No. 3 May - June, 2003
Bruce W. Zoecklein
Department of Food Science and Technology
VPI & SU - 0418
Blacksburg, VA 24061
E-mail: bzoeckle@vt.edu
Web site: http://www.vtwines.info/

I. Tour of Loire River Valley

I recently completed a tour of the Loire River Valley with Pascal Durand from the University of Burgundy, Leslie Weston from Cornell University, and a few additional colleagues. The purpose of the trip was to review viticultural and enological practices and philosophies, in preparation for a Virginia grape/wine industry study tour in March 2004. This will be similar to the study tour we conducted in Southeastern France and the Rhone Valley in December 2003 (full details of this trip, including notes from each vineyard and winery visit, are posted on-line at www.vtwines.info).

For 8 days, we toured along the Loire River, the longest in France (more than 1,000 km). The river ranges from the Central Massif Mountains, the heart of France, to the Atlantic Ocean, with its countless, majestic chateaux. The wine region covers 125,000 acres, half the size of that of Bordeaux, and equivalent to the Rhone’s.

The top variety is the versatile Chenin, also called Pineau of Loire, with wines ranging from light dry to dessert wines, and even fortified products. Two main regions for Chenin include Montlouis and Vouvray in Touraine, and along the river Layon in Anjou. The region of Touraine also grows Gamay à jus noir, which can compete with Beaujolais Nouveau, Grelleau, and an interesting variety called Pinot d'Ancenis.

Cabernet Franc is an important variety of the region. It provides single-variety wines, often lighter than in the Bordelais, but usually elegant. We visited the most well known regions for Cabernet Franc in the Loire around Saumur: Bourgueil, Champigny, and Chinon.

Sauvignon Blanc is also extensively planted and occupies a special position in Northern Loire, where soil and climate allow for the production of very flavorful wines. We visited the main regions, Pouilly Fumé and Sancerre.

We also traveled to the region of Nantes, where two other interesting varieties are grown: Muscadet and Gros Plant. Muscadet, or Melon de Bourgogne, a frost-resistant white variety, generally gives somewhat neutral wines. The winemaking practice, sur lie, gives the wines a touch more complexity.

The Cabernet Franc (or Beton as it is called locally) regions of Touraine, Chinon, Bourgueil, St. Nicholas-de-Bourgueil, and Saumur-Champigny were of particular interest, due to our regional success with this variety. They are in the western end of the region, where the Vienne river flows into the Loire. The two largest and most important are the Bourgueil on the northern bank of the Loire, and Chinon on either bank of the Vienne. Adjacent to the Bourgueil is Saint Nicolas de Bourgueil.

Chinon’s red wines are fresh and light, and resemble those of Bourgueil across the river, although the geology is different. The chalky soils of Chinon are seasoned with sand, and the silicaceous component is said to give the reds their distinctive character and body.

The climate of the Loire is fairly mild year round, a principal reason why kings and nobles can build their magnificent châteaux. Relatively high temperatures from mid-June to mid-August coincide with low rain fall. For the central part of the Loire (tours) the average daily mean temperature for September and October is 16.4 and 11.9, respectively. The average monthly highest maximum temperature for the two months is 29.2 and 23.1 degrees C.

Vines are frequently moisture-stressed in the last stage of ripening. Surprisingly, the average total sunshine hours are about 1900 hours/year, about the same as Champagne.

Some Points Discussed During this Trip:

The importance of organic farming with regard to wine quality. Almost all of the producers stated that they practiced organic farming (no herbicides, only copper sulfate and sulfur spraying). Claude Papin, of Ch. Pierre Bise at Beaulieu sur Layon, stated that with herbicides, the soil becomes death to the world. Some stated that they farmed organically, when they can. Alfonse Mellot, of Domaine de la Moussiere, Sancerre, said that organic farming allowed for approximately 1.0 g/L increase in TA, mainly as a result of an increase in the tartaric acid concentration. The increase in TA is associated with a reduction in pH, and an increase in wine longevity, an important quality component for most French vignerons. He also sprays his vines with tartaric acid, which he believes is taken up by the leaves, and results in an increase in fruit acidity.

Most clean cultivate, and all expressed the relationships between soil aeration, root penetration, and organic farming. There was a stong concensus that the avoidance of herbicides, along with soil aeration, allows roots to penetrate deeply into the soil, rather than laterally. This was reported to slow vine growth, that is, had a disinvigorating impact. Alfonse Mellot stated that organically-grown Cabernet Franc is more concentrated. Organic wines, although more difficult to produce, were reported to command as much as 30% more in the marketplace, according to Michel Delanoue of Domaine de la Nouraraie-Bourgueil.

The rate of fruit maturation was an important topic of discussion. Some of the research we have conducted in Virginia suggests that this may be an important quality feature. Specifically, we have found an inverse correlation between the length of the growing season and wine quality. It appears that the longer the growing season, the lower is the grape glycoside concentration. Grape glycosides are colored anthocyanins and, in part, aroma/flavor precursors. One important reason for the strict AOC yields in France is to make sure that crop loads are not so high as to delay the rate of fruit maturity.

This was particularly evident at Domaine des Rogelins-Varrains Chace. Cabernet Franc parcels of less than a 2-3 acres were surrounded by 7- to 9-foot-high rock walls, not for their fine aesthetic value, but because the increased heat retained advanced the season by an average of 10 days.

Claude Papin, of Ch. Pierre Bise at Beaulieu sur Layon, talked with us about his perceptions of two distinctively different wine styles produced: varietal wines and terroir wines. Varietal wines are those that possess the expression of the grape variety, but are simple products. These wines are from fruit grown in climates and soils that are not optimal. Terroir wines, on the other hand, are more complex, with the full incorporation of the elements which make up fine wine, the soil, the sun, the wind, etc.

He used this as an example as to why he does not grow Sauvignon Blanc in his region. “It would mature three weeks later than in Sancerre, resulting in increased herbaceousness--a simple varietal wine.” Alfonse Mellot, of Domaine de la Moussiere, had a similar comment in a discussion about ‘wine makeup’--too much winemaker intrusion, which hides the true character of the soil and climate.

Not every producer we met was completely Old World in approach. For example, Domaine Henri Bourgeois-Sancerre is a state of the art, gravity flow facility with conveyer belts, computerized system controls, and an elaborate HACCP plan. Christopher Daviau, of Domaine de Bablut at Brissac, uses post-fermentation, and pre- and post-dejuicing microoxygenation on his Cabernet Franc, for more gentle extraction, color stablization, and phenolic polymerization.

Domaine Henri Bourgeois uses a procedure that we have reported, thermal vinification before dejuicing of reds. In our research with Virginia-grown Cabernet Sauvignon, we have heated must to 42 degrees C, post-fermentation, for several hours, cooled down to 15 - 2 degree C and pressed. The result is the increased extraction of skin-derived aroma/flavor precursors (18%) and anthocyanins (12%). Additionally, our research demonstrated an increased association of anthocyanins with non-colored phenols. In one study, we reported an increase of 41% and 208% in the formation of small and large polymeric pigments, respectively. This results in increased spectral color, color stability and palate intergration. Color and color stability were the primary concerns for the Domaine Henri Bourgeois Pinot noir.

I intend to conduct a Winemaker Roundtable meeting to further discuss Cabenet Franc grape/wine production and to taste wines from the trip.

II. Up Coming Meetings

Winemaker Technical Roundtable. July 15. Location TBA. Dominique Delteil will be our guest. Dominique is the director of research and development for the Interprofessionalle Cooperaty du Vin in Montpelhen, France. Dominique has conducted research on yeast selection, and aroma/flavor and mouthfeel. He and I will lead a discussion of phenol management and yeast selection. Details to follow.

Wine Microbiology Workshop July 21, 2003. Location TBA. This day-long program will feature my colleague, Lisa Van de Water, The Wine Lab and Pacific Rim Oenology Service, and will cover practical issues with regard to wine microbiology. I will also cover the subject, Managing Sulfur-Containing Compounds. This will include factors influencing organic and inorganic sulfur compound production, and steps to lower the impact on wine quality. More information to follow. Mark your calendars!

Norton Roundtable. The third annual Norton Roundtable meeting will be conducted at Chrysalis Vineyards, beginning at 1:00 p.m. on July 28, 2003. This meeting is for current Norton grape growers and winemakers. RSVP required. If you are interested in attending, send me an e-mail message at bzoeckle@vt.edu.

Wine Closure Symposium and annual meeting of the American Society for Enology and Viticulture, Eastern Section July 8-11, 2003, Corning, New York. The Closure Symposium (July 9-10) will feature a number of international speakers on practical and relevant subjects including: progress toward elimination of TCA, an overview of cork alternatives, cork QC, screw caps and other wine bottle closures, etc., including sensory analysis. Additional information is available through my office, posted on my website, and posted on the website of the ASEV-ES at www.nysaes.cornell.edu/fst/asev.

If you would like to have your name added or removed from our list serve for future Enology Notes, please send a blank e-mail to bzoeckle@vt.edu with the word "Add" or "Remove" in the subject line.