Zinfandel is a variety of red grape planted

Zinfandel is a variety of red grape planted in over 10 percent of California vineyards. DNA fingerprinting revealed that it is genetically equivalent to the Croatian grape Crljenak Kaštelanski, and also the Primitivo variety traditionally grown in the "heel" of Italy, where it was introduced in the 1700s. The grape found its way to the United States in the mid-19th century, and became known by variations of the name "Zinfandel", a name of uncertain origin.

The grapes typically produce a robust red wine, although a semi-sweet rosé (blush-style) wine called White Zinfandel has six times the sales of the red wine in the United States. The grape's high sugar content can be fermented into levels of alcohol exceeding 15 percent.

The taste of the red wine depends on the ripeness of the grapes from which it is made. Red berry fruits like raspberry predominate in wines from cooler areas, whereas blackberry, anise and pepper notes are more common in wines made in warmer areas and in wines made from the earlier-ripening Primitivo clone.

History

Europe (6000 BCE – 1870)

Archaeological evidence indicates that domestication of Vitis vinifera occurred in the Caucasus region around 6000 BCE, and winemaking was discovered shortly after. Cultivation of the vine subsequently spread to the Mediterranean and surrounding regions. Croatia once had several indigenous varieties related to Zinfandel, which formed the basis of its wine industry in the 1800s. This diversity suggests that the grapes existed in Croatia longer than anywhere else. However, these varieties were almost entirely wiped out by the phylloxera epidemic of the late 19th century, reducing Zinfandel to just nine vines of locally-known "Crljenak Kaštelanski" discovered in 2001 on the Dalmatian coast of Croatia.

The first documented use of the term Primitivo appears in Italian governmental publications of the 1870s. The name derives from the terms primativus or primaticcio, which refer to the grape's tendency to ripen earlier than other varieties. This name's appearance 40 years after the first documented use of the term Zinfandel was previously thought to suggest that Primitivo was introduced to Italy from across the Atlantic; however, this hypothesis became unlikely since the discovery of the vine's Croatian origin.

Primitivo is now thought to have been introduced as a distinct clone into the Apulia region of Italy in the 1700s. Don Francesco Filippo Indellicati, the priest of the church at Gioia del Colle near Bari, selected an early ("primo") ripening plant of the Zagarese variety (the name possibly derived from "Zagreb") and planted it in Liponti. This clone ripened at the end of August and became widespread throughout northern Puglia. Cuttings came to the other great Primitivo DOC (denominazione di origine controllata or "controlled denomination of origin") as part of the dowry of the Countess Sabini of Altamura when she married Don Tommaso Schiavoni-Tafuri of Manduria in the late 1800s.
United States east coast (1829 – 1850)

The arrival of Zinfandel in the United States may have been via the Imperial Nursery in Vienna, Austria, which likely obtained the vines during the Habsburg Monarchy's rule over Croatia, after Dalmatia was absorbed when the Venetian Empire fell in 1797. George Gibbs, a horticulturist on Long Island, received shipments of grapes from Schönbrunn and elsewhere in Europe between 1820 and 1829. Sullivan suggests that the "Black Zinfardel of Hungary" mentioned by William Robert Prince in A Treatise on the Vine (1830) may have referred to one of Gibbs' 1829 acquisitions. Webster suggests that the name is a corruption of tzinifándli (czirifandli), a Hungarian word derived from the German Zierfandler, a white grape (Gruener Sylvaner) from Austria's Thermenregion.

Gibbs visited Boston in 1830, and Samuel Perkins of that city began selling "Zenfendal" soon afterward. In 1830, Gibbs also supplied Prince with "Black St. Peters", a similar variety may have come from England, where many vines have "St. Peters" in their names. Little is known about this vine, except that the Black St. Peters that arrived in California in the 1850s was the same as what became known as Zinfandel by the 1870s.
Bottles of Californian Zinfandel and Primitivo di Manduria.

By 1835 Charles M. Hovey, Boston’s leading nurseryman, was recommending "Zinfindal" as a table grape, and it was soon widely grown in heated greenhouses for the production of table grapes as early as June. The first reference to making wine from "Zinfindal" appears in John Fisk Allen's Practical Treatise in the Culture and Treatment of the Grape Vine (1847). Meanwhile the fad of hothouse cultivation faded in the 1850s as attention turned to the Concord and other grape varieties that could be grown outdoors in Boston.
[California (1850 – 1933)

Prince and other nurserymen such as Frederick W. Macondray joined the California Gold Rush in the 1850s, and took Zinfandel with them. Prince's notebook records that the grape dried "perfectly to Raisin" and that he believed his Zinfandel was the same as the "Black Sonora" he found in California. When the vine known as "Black St. Peters" arrived in California, it was initially regarded as a distinct variety, but by the 1870s it was recognized as the same grape as Zinfandel.

Joseph W. Osborne may have made the first wine from Zinfandel in California. He planted Zinfandel from Macondray at his Oak Knoll vineyard just north of Napa, and his wine was much praised in 1857. Planting of Zinfandel boomed soon after, and by the end of the 19th century it was the most widespread variety in California.

These Zinfandel old vines are now treasured for the production of premium red wine, but many were ripped up in the 1920s, during the Prohibition years (1920–1933), but not for the obvious reason. Even during the Prohibition, home winemaking remained effectively legal, and some vineyards embraced the sale of grapes for making wine at home. While Zinfandel grapes proved popular among home winemakers living near the vineyards, it was vulnerable to rot on the long journey to East Coast markets. The thick-skinned Alicante Bouschet was less susceptible to rot, so this and similar varieties were widely planted for the home winemaking market. Three thousand cars (about 38000 t) of Zinfandel grapes were shipped in 1931, compared to 6000 cars of Alicante Bouschet.
[Rediscovery after Prohibition (1933 – present)

By 1930, the wine industry had weakened due to the Great Depression and Prohibition. Many vineyards that survived by supplying the home market were located in California's Central Valley, a non-optimal environment for growing quality Zinfandel. Thus, the end of Prohibition left a shortage of quality wine grapes, and Zinfandel sank into obscurity as most was blended into undistinguished fortified wines. However, some producers remained interested in making single varietal red wines.

By the middle of the 20th century the origins of California Zinfandel had been forgotten. In 1972, one British wine writer wrote, "there is a fascinating Californian grape, the zinfandel, said to have come from Hungary, but apparently a cépage now unknown there." In 1974 and 1981, American wine writers described it as "a California original, grown nowhere else" and "California's own red grape".

In 1972, Bob Trinchero of the Sutter Home Winery decided to try draining some juice from the vats in order to impart more tannins and color to his Deaver Vineyard Zinfandel. He vinified this juice as a dry wine, and tried to sell it under the name of Oeil de Perdrix, a French wine made by this saignée method. The Bureau of Alcohol, Tobacco and Firearms insisted on an English translation, so he added "White Zinfandel" to the name, and sold 220 cases. At the time, demand for white wine exceeeded the availability of white wine grapes, encouraging other California producers to make "white" wine from red grapes, with minimal skin contact. However, in 1975, Trinchero's wine experienced a stuck fermentation, a problem in which the yeast dies off before all the sugar is converted to alcohol. He put the wine aside for two weeks, then tasted it and decided to sell this pinker, sugary wine. Just as Mateus Rosé had become a huge success in Europe after World War II, this medium sweet White Zinfandel became immensely popular. White Zinfandel still accounts for 9.9% of U.S. wine sales by volume (6.3% by value), six times the sales of red Zinfandel. Most white Zinfandel is made from grapes grown for that purpose in California's Central Valley.

Wine critics considered white Zinfandel to be insipid and uninteresting in the 1970s and 1980s, although modern white Zinfandels have more fruit and less cloying sweetness. Nevertheless, the success of this blush wine saved many old vines in premium areas, which came into their own at the end of the 20th century as red Zinfandel wines came back into fashion. Although the two wines taste dramatically different, both are made from the same (red) grapes, processed in a different way.
[Relationship to Primitivo and Crljenak Kaštelanski
A vine of Crljenak Kaštelanski, in the vineyard where it was discovered. The metal tag from the University of Zagreb indicates that this vine is reserved for genetic research.

Zinfandel was long considered "America's vine and wine", but when University of California, Davis (UCD) professor Austin Goheen visited Italy in 1967, he noticed how wine made from Primitivo reminded him of Zinfandel. Others also made the connection about that time. Primitivo was brought to California in 1968, and ampelographers declared it identical to Zinfandel in 1972. The first wine made from these California vines in 1975 also seemed identical to Zinfandel. In 1975, PhD student Wade Wolfe showed that the two varieties had identical isozyme fingerprints.

Dr. Lamberti of Bari had suggested to Goheen in 1976 that Primitivo might be the Croatian variety Plavac Mali. By 1982 Goheen had confirmed that they were similar but not identical, probably by isozyme analysis. Some Croatians, however, became convinced that Plavac Mali was the same as Zinfandel, among them Croatian-born winemaker Mike Grgich. In 1991 Grgich and other producers came together as the Zinfandel Advocates and Producers (ZAP) with the objectives of promoting the varietal and wine, and supporting scientific research on Zinfandel. With this support, UCD professor Carole Meredith went to Croatia and collected over 150 samples of Plavac Mali throughout Dalmatia, in collaboration with the University of Zagreb.

In 1993, Meredith used a DNA fingerprinting technique to confirm that Primitivo and Zinfandel are clones of the same variety. Comparative field trials have found that "Primitivo selections were generally superior to those of Zinfandel, having earlier fruit maturity, similar or higher yield, and similar or lower bunch rot susceptibility." This is consistent with the theory that Primitivo was selected as an early-ripening clone of a Croatian grape.

By 1998, Meredith's team realized that Plavac Mali was not Zinfandel but rather that one was the parent of the other. In 2000 they discovered that Primitivo/Zinfandel was one parent of Plavac Mali. The other parent of Plavac Mali was determined by Ivan Pejić and Edi Maletić (University of Zagreb) to be Dobričić, an ancient variety from the Adriatic island of Šolta.

This discovery narrowed down the search to the central Dalmatian coastal strip and its offshore islands. Eventually a matching DNA fingerprint was found among the samples. The match came from a vine sampled in 2001 in the vineyard of Ivica Radunić in Kaštel Novi. This Crljenak Kaštelanski ("Kaštela Red") appears to represent Primitivo/Zinfandel in its original home, although some genetic divergence may have occurred since their separation. Meredith now refers to the variety as "ZPC" - Zinfandel / Primitivo / Crljenak Kaštelanski.

This Croatian vineyard contained just nine Crljenak Kaštelanski vines mixed with thousands of other vines. In 2002, additional vines known locally as Pribidrag were found in the Dalmatian coastal town of Omiš. Both clones are being propagated in California under the aegis of Ridge Vineyards, although virus infections have delayed their release. The first Croatian ZPC wine was made by Edi Maletić in 2005. Meanwhile, plantings of Primitivo have increased in California, where it seems to grow somewhat less vigorously than its sibling. Its wines are reputed to have more blackberry and spice flavors.
[Legal issues

Local wine-labeling regulations are slowly catching up with the DNA evidence, a process that has been slowed by trade disputes. The European Union recognized Zinfandel as a synonym for Primitivo in January 1999, meaning that Italian Primitivos can be labelled as Zinfandel in the United States and any other country that recognises EU labelling laws. Italian winemakers have taken advantage of these rules and shipped Primitivo wines to the United States labelled as Zinfandels, with the approval of the Alcohol and Tobacco Tax and Trade Bureau (TTB).

As of December 2007, the TTB lists both Zinfandel and Primitivo as approved grape varieties for American wines, but they are not listed as synonyms. U.S. producers, therefore, must label a wine according to whether it is Zinfandel or Primitivo. The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) proposed in 2002 that they be recognised as synonyms, but no decision on this proposal (RIN 1513–AA32, formerly RIN 1512-AC65) has been made.
[Distribution and wines
[United States

Zinfandel is most widely known in the California wine industry, but the grape is also grown in Arizona, Colorado, Illinois, Indiana, Iowa, Massachusetts, Nevada, New Mexico, New York, North Carolina, Ohio, Oregon, Tennessee, Texas and Washington. U.S. producers make wine in styles that range from late harvest dessert wines, rosés (White Zinfandel) and Beaujolais-style light reds to big hearty reds and fortified wine in the style of port. The quality and character of American Zinfandel wines largely depend on the climate and location in which they are grown, the age of the vineyard in which they are grown, and the technology employed by the winemaker.

Historically, California Zinfandel vines were planted as a field blend interspersed with Durif (Petite Sirah), Carignan, Grenache, Mourvèdre, Mission and Muscat. While most vineyards are now fully segregated, California winemakers continue to use other grapes (particularly Petite Sirah) in their Zinfandel wines. Zinfandel is grown on approximately 11% of California's vineyard land area. Around 400,000 short tons (350,000 tonnes) are crushed each year, depending on the harvest, placing Zinfandel third behind Chardonnay and Cabernet Sauvignon and just ahead of Merlot.
[California regions

In California, 20% of the Zinfandel-growing counties hold 80% of the Zinfandel growing area; however, major producing areas such as San Joaquin County, Stanislaus County, and Madera County produce Zinfandel primarily for blends or jug wine.

Certain California regions are regarded as "exceptional" for Zinfandel, each with identifiable flavor characteristics.

* Amador has a reputation for big, full-bodied Zinfandel. These extra-ripe wines have been called jammy, briary, and brambly, having aromas of sweet berries.
* Although the Santa Cruz Mountains AVA in Santa Clara Valley produces Zinfandel from just 9 acres (3.64 hectares), the Zinfandel from that region is known for its complexity and depth.
* Sonoma county has a Zinfandel-producing land area second only to that of San Joaquin County. The county contains the warm Dry Creek Valley AVA, known for its juicy Zinfandel with bright fruit, balanced acidity and notes of blackberry, anise and pepper. Dry Creek Valley produces Zinfandel in a variety of styles ranging from the high-alcohol Amador style to balanced, spicy wines.
* San Luis Obispo, particularly the Paso Robles AVA with its hot days and cool maritime evenings, produces Zinfandel known for being soft and round.
* While the Napa Valley AVA is known primarily for its Cabernet Sauvignon, Merlot, and Syrah, Napa also produces Zinfandel wines described as plummy and intense, tasting of red berry fruits with cedar and vanilla. Zinfandel in Napa tends to be made in a claret style like red Bordeaux.
* The Russian River Valley generally produces well during warm vintages. Otherwise, the grapes do not fully ripen, leaving the wines with excessive acidity. The area has mostly "old vine" Zinfandel, characterized as spicy and somewhat lower in alcohol than Zinfandel from other regions.
* Mendocino County Zinfandel wines have been considered high quality, but they are less known because they are not heavily marketed.
* Lodi has some of the oldest Zinfandel vines in California. While often used for White Zinfandel production, in the red style, Lodi Zinfandels have a reputation for being juicy and approachable.

[Italy

Most Primitivo is grown in Puglia (Apulia), the "heel" of Italy, and it is estimated to be the country's 12th most widely planted grape variety. The main three DOC areas are Primitivo di Manduria, Gioia del Colle Primitivo (Riserva) and Falerno del Massico Primitivo (Riserva o Vecchio). The Manduria DOC covers still red wine as well as sweet (Dolce Naturale) and fortified (Liquoroso Dolce Naturale, Liquoroso Secco) wine. Falerno requires a minimum of 85% Primitivo; the others are 100% Primitivo. Gioia del Colle Rosso and Rosato contain 50-60% Primitivo, and Cilento Rosso/Rosato contains around 15%.

Historically, the grape was fermented and shipped north to Tuscany and Piedmont where it was used as a blending grape to enhance the body of thin red wines produced in those areas. When the link between Primitivo and Zinfandel began to emerge, plantings in the region and production of non-blended varietal increased. Today most Italian Primitivo is made as a rustic, highly alcoholic red wine with up to 16% alcohol by volume (ABV). Some Italian winemakers age the wines in new American oak to imitate American-style Zinfandel.
[Other locations

The Croatian form Crljenak Kaštelanski was not bottled in Croatia as a varietal in its own right before the link to Zinfandel was revealed. UCD has since sent clones of both Zinfandel and Primitivo to Professor Maletić in Croatia, which he planted on the island of Hvar. He made his first ZPC wines in Croatia in 2005. There is high demand for red grapes in the country, and the government has been supportive of ongoing research. Figures from the department of viticulture and enology at the University of Zagreb claim that from only 22 vines of Crljenak Kaštelanski in Croatia in 2001, there were about 2,000 vines in 2008.

Old vine Zinfandel plantings dating from the 1930s have been found in Baja California, Mexico. There are also small Zinfandel plantings in South Africa, Western Australia and the McLaren Vale area of South Australia.
[Viticulture and winemaking
Zinfandel wine fermenting in barrels.

Zinfandel vines are quite vigorous and grow best in climates that are warm but not too hot, because grapes may shrivel in hot weather. Zinfandel's thin-skinned grapes grow in large, tight bunches that are sometimes prone to bunch rot. The fruit ripen fairly early and produce juice with high sugar levels. If weather conditions permit, the grapes may be late-harvested to make dessert wine. Zinfandel is often praised for its ability to reflect both its terroir and its winemaker's style and skill.

The grapes are known for their uneven pattern of ripening: a single bunch may contain both raisin-like, over-ripe grapes and green, unripened grapes. Some winemakers choose to vinify the bunches with these varying levels of ripeness, while others hand-harvest the bunches, even by single berries, through multiple passes through the vineyards over several weeks. This extensively laborious practice is one component in the high cost of some Zinfandels.

Red Zinfandel wines have been criticized for being too "hot" (too alcoholic), although modern winemaking techniques have helped make them more approachable. On the other hand, Zinfandel producers such as Joel Peterson of Ravenswood believe that alcohol-removing technologies, such as reverse osmosis and spinning cones, remove a sense of terroir from the wine. If a wine has the tannins and other components to balance 15% alcohol, Peterson argues, it should be accepted on its own terms.

When grapes are harvested, the length of fermentation, the length of the maceration period with skin contact and the level of oak aging affect the wine's taste. The degrees Brix at which the grapes are harvested dramatically affect the wine's flavor as well. White Zinfandel is normally harvested early at 20°Bx when the grapes have yet to develop much varietal character, though some examples can develop hints of tobacco and apple skin. At 23°Bx (the degree that most red wine is considered "ripe"), strawberry flavors develop. Cherry flavors appear at 24°Bx followed by blackberry notes at 25°Bx.