UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION BERKELEY, CALIFORNIA CIRCULAR 356 August, 1943 GRAPE VARIETIES FOR WINE PRODUCTION 1 M. A. AMERINE 2 and A. J. WINKLER 3 Although California Wineries have utilized a considerable tonnage of raisin and table grapes since repeal of Prohibition, their preferred material is wine grapes. In this state there are now only 170,000 acres of such grapes, pro- ducing about 600,000 tons per year. The average annual winery crush (1937 to 1941) has exceeded 900,000 tons, but the annual crush of wine grapes has not exceeded 450,000 ; hence wine grapes have constituted approximately only 50 per cent of the total crush. 4 Should normal winery demands continue, the acreage of wine grapes could probably be expanded with profit. The grower is interested in planting varieties that produce well, but the consumer is con- cerned with securing a product of good quality. Interest in wine-grape adaptation to the climatic regions of California has extended from the time of Agoston Haraszthy in 1860 to the present. From 1880 until Prohibition, the California Agricultural Experiment Station con- ducted detailed studies, first under Dean E. W. Hilgard, later under Professor F. T. Bioletti. Since Prohibition repeal the studies have been continued, and the present circular summarizes the best information available. Table wines may be either sweet or dry. They contain less than 14.0 per cent of alcohol, and the dry types should have over 0.6 per cent acid. The sweet types contain 0.5 to 5.0 per cent sugar and appear balanced with only about 0.5 per cent acid. The best grapes for the standard dry types should not exceed 24° Balling nor have a must aciditj^ of less than 0.65 per cent. The natural sweet types of table wines will require musts with a Balling degree of 24 to 28, because it is necessary to maintain residual sugar in them; yet their acidity should be about 0.60 per cent. Dessert wines also may be either sweet or dry. They contain over 18.0 per cent alcohol. Since this concentration is not easily obtained by natural 1 This publication summarizes the recommendations of the Hilgardia article, Composition and Quality of Wines and Musts of California Grapes, by M. A. Amerine and A. J. Winkler (in press). Those interested in more complete information on the merits and defects of specific varieties should write to the Division of Viticulture at Davis stating the varieties, the proposed region of planting, and the type and quality of wine desired. 2 Assistant Professor of Enology and Assistant Enologist in the Experiment Station. 3 Professor of Viticulture and Viticulturist in the Experiment Station. 4 For more complete data see Bulletin 651, Commercial Production of Dessert Wines, by M. A. Joslyn and M. A. Amerine. The percentage of wine grapes in the crush increased in 1942 because of the almost complete diversion of raisin grapes to drying. [1] 2 University of California — Experiment Station fermentation, grape spirits must be added during or after the fermentation to give the required amount of alcohol. The more alcohol produced by fer- mentation, the smaller the amount required to arrest the fermentation. Musts of high Balling readings (over 24) are therefore preferable for making des- sert wines. Such musts also yield wines with a higher extract content. The grapes should not, however, remain on the vines until they have become rais- ined and have lost their fruitiness. Since a sweet-sour taste is undesirable, the acid concentration should be only moderate — from 0.4 to 0.6 per cent in the finished wine is considered desirable. If the acidity is below 0.4 per cent, the wine is likely to taste flat and be unpalatable. Fig. 1. — Vineyard on low coastal hills, region I. Note the redwood stumps. (Courtesy of the Wine Institute.) The term "high-quality" as used here will describe wines whose character and composition favor the maturation of the wine in the wood or the bottle. A "standard" product is a sound wine that lacks the flavor, the composition, or both, to develop much character by aging. This is no condemnation of standard young wines, which have a very definite place in the industry. Dry white wines in particular can be sold early. INFLUENCE OF ENVIRONMENTAL CONDITIONS Regional Environment. — The environmental-varietal interrelation is com- plicated but important. Under cool conditions ripening proceeds slowly ; the mature grapes retain a higher degree of acidity, have a lower pH ; and red grapes possess much more coloring matter than those grown under warm con- ditions. These conditions favor the production of musts that are well suited for table wines. Under relatively warm ripening conditions, high sugar and moderate acidity are secured. Musts of such grapes are best suited for dessert wines. With some varieties the composition and flavor in certain regions is so superior that typical wines of high quality have been developed. California has a wide range of climatic conditions. Utilizing the differences Cm. 356] Grape Varieties for Wine Production 3 in the temperature or more specifically the summation of heat as degree-days 5 above 50° F for the period April 1 to October 31, the grape-producing area of the state may be conveniently divided into five climatic regions. These regions, together with representative localities, are : Region I (less than 2,500 degree-days) : Napa and Oakville in Napa County; Hollister and San Juan in San Benito County; Woodside in San Mateo County; Mission San Jose and Saratoga in Santa Clara County; Bonny Doon and Vinehill in Santa Cruz County; and Guerneville, Santa Rosa, and Sonoma in Sonoma County. Figure 1 shows a typical vineyard.) Vineyard on hillside in region II. (Courtesy of the Wine Institute.) Region II (2,501 to 3,000 degree-days) : Soledad in Monterey County; Rutherford, St. Helena, and Spring Mountain in Napa County ; Santa Barbara in Santa Barbara County ; Almaden, Evergreen, Guadalupe, and Los Gatos in Santa Clara County; and Glen Ellen in Sonoma County (fig. 2). Region III (3,001 to 3,500 degree-days) : Livermore and Pleasanton in Alameda County ; Calpella, Ukiah, and Hopland in Mendo- cino County ; Calistoga in Napa County ; Alpine in San Diego County ; Templeton in San Luis Obispo County ; Loma Prieta in Santa Clara County ; and Alexander Valley, Asti, and Cloverdale in Sonoma County (fig. 3). Region IV (3,501 to 4,000 degree-days) : Guasti in San Bernardino County; Escondido in San Diego County; Acampo, Escalon, Lockeford, Lodi, and Manteca in San Joaquin County; Cordelia in Solano County; Ceres, Hughson, and Vernalis in Stanislaus County; Ojai in Ventura County; and Davis in Yolo County (fig. 4). Region V (4,001 or more degree-days) : Fresno and Sanger in Fresno County; Madera in Madera County; Arena and Livingston in Merced County; and Trocha in Tulare County (fig. 4). 5 For example, if the mean temperature for a period of 5 days was 70° F, the summation would be (70°-50°) x 5 = 100 degree-days; and, if the mean temperature for June was 65°, the summation would be (65°-50°) x 30 = 450 degree-days. University of California — Experiment Station ... l ■:...?,- r-y?. ";.;/': Fig. 3. — Vineyard in the Livermore Valley, region III. Note the very coarse, gravelly texture of the soil. (Courtesy of the Wine Institute.) ■ , - '" .■"■■■■ '. - - * " &■ ; — -••*• u ^Sllilll . 4 **,«- W<> ^ ^ * * i :2i ;; : •# BEEfe • > , * ^ \ ,"';«*■ • n: Fig. 4. — A typical midsummer scene in a vineyard in regions IV and V. (Courtesy of the Wine Institute.) Regions I and II should produce the best table wines ; IV and V, the best dessert wines. When mature, only a few varieties will retain enough acidity to produce good table wines in regions IV and V, while only in a very hot season or in an exposed vineyard with an early variety will regions I and II produce grapes ideally suited for dessert wines. Cm. 356] Grape Varieties for Wine Production 5 Seasonal Conditions. — Although grapes reach maturity practically every year in most parts of California, their composition is not always the same. In a warm season the color content and titratable acidity are lower, and the pH is higher, than in a cool season. Such are the differences between certain years that a moderately acid variety, normally best suited for table wine, may sometimes become better adapted for dessert wine. This is particularly true in the regions of intermediate temperature ; namely II, III, and IV. CHOICE OF VARIETY Whereas a few varieties can produce high-quality wine, many others be- cause of unfavorable composition, neutral flavor, or susceptibility to rot or disease can never produce a fine wine. Fortunately there is a large demand for ordinary wines of sound character and low cost. If the grower chooses to produce this latter type, varieties that produce heavy crops should be planted. On the other hand, there is a limited but definite and growing demand for fine wines. Unfortunately, the varieties capable of producing such wine are only poor to moderate producers. The regional conditions suitable for fine wines also put a definite upper limit on the amount of crop that can be matured normally. Thus, planting heavy-producing varieties on poor soils of cool areas will not yield grapes capable of producing high-quality wines. Likewise, the planting of poor-producing varieties on fertile soil in warm regions is not a proper utilization of the land. Composition of Musts. — As already indicated, varieties for table wines should attain a normal maturity and yet retain an acidity of at least 0.65 per cent or higher, whereas dessert-wine varieties should have at least 24° Balling and only a moderate acidity. The pH of grapes for table wines should, if pos- sible, be below 3.3, while that of dessert wines may be as high as 4.0. The higher the pH, however, the greater the care necessary during fermentation to pre- vent spoilage by bacteria. The best red-wine grapes contain sufficient color and acidity, though when grown in too warm a region or season even those whose skins normally have sufficient coloring matter will produce poorly colored wines. The amount of color is particularly important for port varieties. The grapes recommended should of course mature without undue rotting, sunburning, or raisining. The clusters should not be too tight, nor subject to shattering. For standard-quality wines, in order to reduce picking costs, large clusters are preferred. The skins should be thick enough to reach the winery in good condition. The stems and berries should be easily separated by a mechanical stemmer. Although ordinary wines can be prepared from varieties with a large berry, the better-flavored wines require a smaller berry size because of the more favorable surface-volume relation for extracting flavor and color from the skins. Time of Maturation. — Early-ripening varieties are at a disadvantage in California : they mature in the warmest part of the growing season ; and the ripening changes proceed too rapidly, so that low acid, excessive sugar, and sunburning ordinarily result. Varieties that mature in midseason are also considered better from the wine maker's point of view, since he can then crush them when fermentation temperatures are lower. Although late-ripening va- rieties have the advantage of lengthening the season, they run the risk of being spoiled by early rains. University of California — Experiment Station RECOMMENDED VARIETIES Only varieties that yield the best product for their type — whether standard, quality red or white table, or red or white dessert wines — are listed in table 1. Varieties that cannot be unqualifiedly recommended are listed later. Varieties for Region I. — Region I contains few fertile soils that are, or may well be, planted to vines. As a rule only hillside slopes of very moderate fertil- ity are available for grapes. Heavy-bearing varieties should not be planted, since the region cannot produce them in competition with warmer and more fertile districts. In general, white varieties should be preferred to red. Recom- mended white varieties for high-quality dry table wines are White Riesling, Chardonnay, and Sauvignon blanc, the first two being the most desirable. Red Traminer, though useful, should be planted only in the very coolest locations for producing an aromatic wine, and is not ordinarily recommended. Sylvaner is not suited to this region, being oversusceptible to mildew in foggy locations. Varieties such as Burger and Folle blanche should be avoided because they will not ripen. Recommended red varieties for high-quality table wines are Cabernet Sauvignon and Pinot noir ; for standard table wines, Gamay Beau- jolais and Grenache. Varieties for Region II. — Region II contains both valley-floor and hillside vineyards. The former should produce most of the standard red and white table wines of California. The less productive hillside vineyards, though unable to compete for a standard product, can yield fine wines. Recommended white varieties for high-quality dry table wines are Chardonnay, Pinot blanc, White Riesling, and Sauvignon blanc (the last-mentioned usually for natural sweet wine). Recommended white varieties for standard or for blended dry table wines are Semillon (for dry or natural sweet wine), Sylvaner, and Folle blanche. Red Veltliner, though useful, is less desirable and is not ordinarily recommended. The recommended red variety for high-quality table wines is Cabernet Sauvignon; for standard wines, Grenache, Petite Sirah, or Refosco. Also of possible utility for standard wines, but less desirable, are Mondeuse and Tannat. Varieties for Region III. — The warm conditions bf region III favor grapes of higher sugar content, without too much sunburning and too little acidity. Although most of the vineyards are on fairly flat land, some of the soils are rocky and of low productiveness. The better-quality natural sweet wines come from the latter soils. It is a mistake to hope to produce dry wines of the finest quality every year in this region, even on the less fertile soils, since the sum- mation of heat is usually too great. Excellent natural sweet wines should, however, be secured ; and, on the more fertile soils, good standard whites and reds. Trousseau, though not recommended because of the production cost, will produce very good red dessert wines. Recommended white varieties for natural sweet wines are Semillon, Sauvignon blanc, and Muscat Canelli (by itself) ; for standard wines, Pinot blanc, and French Colombard (Winkler, Wests Prolific) . Also of possible utility for standard wines, but not ordinarily recommended, are Folle blanche and Peverella. Recommended red varieties G The varieties listed are as grown under these names in the variety collection of the Uni- versity Farm at Davis. Since not all have been identified with certainty, some of the names may be changed later. The current identification can be obtained from later publications of this station or from the Division of Viticulture, Davis. 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Its clusters are large, compact, and very subject to handling injuries and to damage by rain. The fruit lacks acid ; and its wines, used straight, are deficient in flavor and character. Their neutrality and plainness has given them recognition for blending to reduce excesses in other wines. In the cooler regions the Burger is surpassed even for blending by Servant, which is like- wise neutral, but which possesses a more favorable acidity. Neither variety is adapted to the interior valleys; here the French Colombard may merit con- sideration. The Muscat of Alexandria is pre-eminently a raisin grape. Because it tends to raisin on the vines, and because its flavor is not pronounced until the fruit is fully ripe, it does not readily produce quality wines in many areas. With great care in harvesting, good dessert wines may be obtained. The flavor is not equal to that of several of the muscat varieties recommended previously. Of the other white varieties with a limited recommendation, the Aligote, Red Traminer, and Red Veltliner are deficient in acid for producing quality wines in most areas. In localities where their musts are well balanced they will merit planting. The Peverella and Vernaccia Sarda are fairly well sup- plied with acid and yield mildly distinctive wines, but they have been insuffi- ciently tested. The Gray Riesling, Inzolia bianca, and Verdelho are deficient in acid for dry table wines, and not productive enough to compete with the highly productive dessert-wine varieties, except under special conditions. The Chenin blanc and Muscadelle show more than average promise for sweet table wines. Bed Varieties. — Most of the varieties listed here are suitable for red table wines in one or more regions. All, however, have one or more defects that limit their usefulness. Included are Aramon, Beclan, Bolgnino, Charbono, Fresia, Grignolino, Gros Manzenc, Lagrain, Mammolo Toscano, Meunier, Mondeuse, Nebbiolo, Negrera Gattinara, Raboso Piave, Saint Macaire, Tinta Cao, Val- depenas, and Zinfandel. Also listed is a variety that produces blending wines, Alicante Ganzin ; two dessert- wine varieties, Black Malvoisie and Tinta Cao ; and a muscat-flavored variety, Muscat Hamburg. Though the Aramon has never produced a quality wine, its wines in the cooler regions are distinctly fruity, mature rapidly, and are markedly free of vinification difficulties. Except for pink wines the variety is deficient in color. It is a tremendous producer. The Black Malvoisie produces only standard-quality red dessert wines but may be used, in addition, as a table grape. Its clusters and berries are very large and attractive. It will not produce dry table wines. The Grignolino is a moderate producer. Its clusters are large and handle well. Its wine has a distinctly varietal aroma and flavor, appealing strongly to those who like it, but not meeting with general favor. It is high in tannin but only light orange-red in color. The Gros Manzenc is a moderate producer with long spur pruning. Its medium-sized clusters handle well. Its wines are distinctive, fresh to tart, wel] balanced, and well colored. Perhaps it should displace some of the Carignane. Zinfandel, or Petite Sirah in certain localities of regions III and IV. 14 University of California — Experiment Station The Mondeuse, a heavy producer, tends to mature its fruit poorly. Though of average acid content and distinct aroma, its wines have been only of stand- ard quality in the coastal areas. They have tended to be somewhat coarse and lacking in finish, better suited for blending than for aging straight. The Saint Macaire is only moderately productive. Its fruit is not covered sufficiently to prevent sunburning in warm seasons. The wines are heavy and full-bodied, with intense color. They require long aging. For blending, in regions IV and V, their acid, color, tannin, and body may have value. The vines of Sangioveto are vigorous, but only moderately productive. The wines are well balanced as regards acidity, body, tannin, and color, and are distinctive in aroma and flavor. This variety should replace some of the bulk sorts in certain localities in regions III and IV. The Tannat is vigorous and moderately productive, with medium-large clusters that handle well. In the coolest areas its wines have considerable character, are delicate and balanced. Under somewhat warmer conditions, however, they tend to be coarse and tannic, and to require too much time to mature in the wood. The Valdepenas is both vigorous and productive. Its clusters are large and resist handling injuries. Its musts have regularly been too low in acid to pro- duce balanced dry table wines. In the cooler areas where the acidity of the fruit is higher, the variety is subject to mildew and bunch rot. Its dessert wines are generally better balanced, but they tend to be astringent. The Zinf andel is very widely planted in California. It ships fairly well, and its distinct varietal aroma and flavor are passed on to the wine. When sound, uniformly well-matured fruit is used, the Zinf andel produces a well-balanced, fruity, distinctive wine of average quality. In region IV it has also yielded standard red dessert wines. The variety possesses, however, the defect of ripening its fruit unevenly; some berries may be raisining before others are more than changing from pink to red. Because of its compact clusters it is also very subject to bunch rot during humid periods or after rains. Of the other red varieties of limited recommendation, Beclan and Charbono can justify places for themselves only in the cooler areas where their resistance to mildew offsets their lack of vigor or their other defects. Bolgnino, Fresia, Nebbiolo, Mammolo Toscano, Negrera Gattinara, and Raboso Piave produce well-balanced wine of greater or less distinctive aroma and flavor and above- average quality ; but they are deficient in productivity or in some property of the wine, such as color and finish. In the interior the Lagrain may have some value because of its intense and stable color, and in coastal counties the early-maturing Limberger might be used to lengthen the harvesting season. Muscat Hamburg shows promise for sweet table wines. Although Tinta Cao is only moderately productive, its fruit withstands unfavorable weather con- ditions much better than the other red dessert-wine varieties. In quality its wines are standard or better. VARIETIES NOT RECOMMENDED Many varieties are so devoid of merit that they cannot be recommended any- where in California under present conditions. The wine grapes listed below fail for various reasons to qualify as varieties recommended for planting. The most common objections are lack of sufficient sugar, acid, or both, low Cir. 356] Grape Varieties for Wine Production 15 production, and susceptibility to rot or diseases. Some varieties listed here have flavor, but in quality or production are so inferior to other closely related varieties that they need not be considered. White varieties not recommended include Bombino bianca, Clairette blanche, Feher Szagos, Green Hungarian, Hibron, Hungarian Millenium, Kleinberger, Malmsey, Marsanne, Mathiasz y-ne, Mourisco branco, Muscat Pantellana, Muscat Saint Laurent, Nasa Veltliner, Nicolas Horthy, Palaverga, Pavai, Roussette, Saint Emilion, Sauvignon vert, Selection Carriere, Steinschiller, Terret, Vermentino Favorita, and Vernaccia bianca. Red varieties not recommended include Alicante Bouschet, Antibo, Aspiran noir, Black Hamburg, Black Prince (Rose of Peru), Blaue Elbe, Bonarda, Chauche noir, Chenin noir, Coristano, Criolla Mesa, Criolla Vino, Croetto Moretto, Dolcetto, Early Burgundy, Grand noir, Grec rouge, Grosse blaue, Kadarka, Koptcha, Lambrusche Langhre, Lenoir, Macaroli, Marzemino, Mataro, Meunier, Negro Amaro, Neiretta, Pagadebito, Petit Bouschet, Petite Verdot, Pf effer, Picpouie noir, Pinot Pernand, Pinot Saint George, and Tinta amarella. 20m-9,'43(6623)