[1] DNA analysis has revealed that it is genetically equivalent to the Croatian grapes Crljenak Kaštelanski and Tribidrag, as well as to the Primitivo variety traditionally grown in Apulia, Italy, where it was introduced in the 18th century, and Kratošija in Montenegro and Macedonia .

These varieties were almost entirely wiped out, however, by the phylloxera epidemic of the late 19th century, eventually reducing Zinfandel to just nine vines of locally-known "Crljenak Kaštelanski" discovered in 2001 on the Dalmatian coast of Croatia.

[8] 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 has become unlikely since the discovery of the vine's Croatian origin.

[10] The arrival of Zinfandel in the United States may have been via the Imperial Nursery in Vienna, Austria, which probably obtained the vines during the Habsburg monarchy's control over the Dalmatian territories of the former Republic of Venice.

[11] 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's 1829 acquisitions.

Webster suggests that the name is a modification of the Hungarian tzinifándli (czirifandli), which derives from the German Zierfandler,[13] a white grape (Grüner Sylvaner) from Austria's Thermenregion.

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.

[11] Prince and other nurseryman, such as Frederick W. Macondray (future son-in-law of Faxon Atherton), 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.

Smith listed "Black St. Peter's" among the 24 grape varieties he was propagating in a sales catalog in 1856 and he exhibited "Zeinfindall" at the state fair in 1858.

[14][15] Joseph W. Osborne planted Zinfandel from Macondray at his Oak Knoll vineyard just north of Napa, and his wine was much praised in 1857.

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.

[20] Many vineyards that survived by supplying the home market were located in California's Central Valley, a non-optimal environment for growing quality Zinfandel.

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.

[23] In 1972, Bob Trinchero of the Sutter Home Winery decided to try draining some juice from the vats to impart more tannins and color to his Deaver Vineyard Zinfandel.

[24] The Bureau of Alcohol, Tobacco and Firearms insisted on an English translation, so he added "White Zinfandel" to the name, and sold 220 cases.

[24] Just as Mateus Rosé had become a huge success in Europe after World War II, this medium sweet White Zinfandel became immensely popular.

[16] With this support, UCD professor Carole Meredith went to Croatia and collected over 150 samples of Plavac Mali[33] throughout Dalmatia, in collaboration with the University of Zagreb.

[33] 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.

After years of research and DNA testing of vines from vineyards across the globe, a single 90-year-old grapevine from the garden of an elderly lady in Split, Croatia provided the evidence to show that Zinfandel was a Croatian grape that had been known as Tribidrag since at least the 15th century.

[41] Italian winemakers have taken advantage of these rules and shipped Primitivo wines to the United States labeled as Zinfandels,[16] with the approval of the Alcohol and Tobacco Tax and Trade Bureau (TTB).

The quality and character of American Zinfandel wines largely depend on the climate, location, and age of the vineyard in which they are grown, as well as 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.

[1] 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.

[45] Red Zinfandel wines have been criticized for being too "hot" (too alcoholic),[4] 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.