Zinfandel Discovery: DNA Analysis Links California, Puglia, and Croatia

The December 2001 discovery by Carole Meredith's team at UC Davis, in collaboration with Croatian scientists Ivan Pejić and Edi Maletić of the University of Zagreb, fundamentally altered understanding of Zinfandel's origins. The matching vine was found not in Italy, as many had assumed, but in the Dalmatian village of Kaštel Novi, in the vineyard of Ivica Radunić. The variety's oldest documented name, Tribidrag, appears in a Croatian record from 1444. It spread to Puglia in the 18th century, where it became Primitivo, and arrived in California likely via the Schönbrunn imperial nursery collection in Vienna, from which Long Island horticulturist George Gibbs received cuttings in the 1820s. By the early 1850s, Captain Frederick Macondray is credited with bringing cuttings from Boston to California.

• Crljenak Kaštelanski translates as 'Kaštela Red' and is also known locally as Tribidrag and Pribidrag; the name Kratošija is used in Montenegro
• Tribidrag is the earliest documented name, attested in 1444 by a priest in Vodice, Dalmatia, then part of the Venetian Republic
• The grape spread to Puglia in the 18th century, where it became known as Primitivo, a name derived from Latin for 'first to ripen'
• Crljenak Kaštelanski is a parent of Plavac Mali, Croatia's most widely planted red variety, not the other way around as was once believed

The three regions producing genetically identical wine showcase dramatically different Mediterranean-influenced climates that profoundly shape each wine's expression. Kaštela sits on the Dalmatian coast with Adriatic breezes moderating temperatures, while limestone soils and steep slopes of up to 45 degrees encourage salinity and strong tannins. Puglia's Primitivo di Manduria vineyards occupy the hot, flat Salento peninsula along the Gulf of Taranto, with ancient alberello-trained vines in calcareous clay-limestone soils. California's Zinfandel belt spans from the coastal benchlands of Dry Creek Valley in Sonoma, where limestone soils parallel Dalmatian conditions most closely, to warm inland regions such as Lodi, Paso Robles, and Amador County, each yielding markedly different expressions of the same variety.

• Kaštela, Dalmatia: limestone and marl soils, steep coastal slopes, salt-influenced by the Adriatic; Crljenak Kaštelanski is considered most comparable to Dry Creek Valley Zinfandel in character
• Puglia (Primitivo di Manduria): calcareous clay-limestone, hot and dry Mediterranean climate, ancient alberello vine training on the Salento peninsula; DOC covers Taranto and Brindisi provinces
• Dry Creek Valley, Sonoma: gravelly benchland soils, moderate Pacific influence; home to century-old Zinfandel field blends including Lytton Springs, widely regarded as a benchmark site
• Lodi and Paso Robles: alluvial and sandy soils with older vine plantings from the late 19th and early 20th centuries; Paso Robles old-vine sites such as Dusi Vineyard (planted 1923) produce deeply concentrated wines

While genetically identical, the three regional expressions diverge significantly due to terroir, climate, and winemaking tradition. Croatian Crljenak Kaštelanski, rarely bottled as a varietal before the 2001 discovery, tends toward fuller tannins, deep color, and dark berry fruit with a distinctive salinity from coastal soils. Primitivo di Manduria, which must contain at least 85 percent Primitivo, has a minimum ABV of 13.5 percent for its dry style, a threshold described as the highest minimum alcohol requirement for any dry unfortified wine appellation in the world. The sweet Dolce Naturale DOCG style requires 100 percent Primitivo and a minimum of 50 grams per liter residual sugar from natural drying on the vine. California Zinfandel spans the widest range, from elegant, structured Dry Creek field blends to rich, warm-climate expressions from Lodi and Paso Robles.

• Crljenak Kaštelanski: deep color, firm tannins, dark berry fruit, and coastal salinity; winemaking tradition was reestablished after 2001 with the variety previously having no commercial varietal bottlings
• Primitivo di Manduria DOC (since 1974): minimum 85 percent Primitivo, minimum 13.5 percent ABV for dry style; Riserva requires 24 months aging, at least 9 in wood, and minimum 14 percent ABV
• Primitivo di Manduria Dolce Naturale DOCG (since 2011): 100 percent Primitivo, grapes partially dried on the vine, minimum 50 g/L residual sugar, minimum 16 percent potential alcohol
• California Zinfandel: ranges from complex, savory field blends of century-old vines in Dry Creek and Sonoma to ripe, fruit-forward styles from Lodi; White Zinfandel, a semi-sweet blush style popularized by Sutter Home in the 1970s-80s, historically outsells red Zinfandel sixfold in the US

The 2001 discovery catalyzed a revival of Crljenak Kaštelanski in Croatia, with family wineries in Kaštela, including Bedalov, Vuina, Krolo, and Radunić, among the first to produce it as a varietal wine. Croatian-American winemaker Mike Grgich of Grgich Hills Estate in Napa Valley, who had long suspected a connection between Croatian and California vines, became a prominent advocate for the variety's heritage. In Italy, the Consorzio di Tutela del Primitivo di Manduria, founded in 1998, supports producers across the DOC and DOCG zones. California's benchmark Zinfandel producers include Ridge Vineyards, which has produced its Lytton Springs Zinfandel from Dry Creek Valley's century-old vines continuously since 1972, and Turley Wine Cellars, founded in 1993 by Larry Turley, which now makes over 50 wines from more than 50 old-vine vineyards across California.

• Kaštela producers (Croatia): Bedalov, Vuina, Krolo, and Radunić produce Crljenak Kaštelanski from the original Kaštela area; Rizman, Stina, and Mimica among broader Dalmatian producers
• Grgich Hills Estate (Napa): Croatian-American Mike Grgich championed the Crljenak connection and has been a leading ambassador for the variety's shared heritage with California Zinfandel
• Ridge Vineyards (Dry Creek Valley): Lytton Springs first bottled in 1972 from vines planted at the turn of the 20th century; vineyard purchased outright in 1990-1991; the 2022 vintage marked the 50th consecutive bottling
• Turley Wine Cellars (founded 1993): makes 50 separate wines from over 50 vineyards across California, primarily old-vine Zinfandel and Petite Syrah, all farmed organically with native yeast fermentations

The DNA discovery underpinned formal legal and institutional recognition of Crljenak Kaštelanski as an authentic Croatian indigenous variety. In Italy, Primitivo di Manduria has carried DOC status since 1974 and requires a minimum of 85 percent Primitivo with a dry-style minimum alcohol of 13.5 percent, described as the highest floor for any unfortified dry wine appellation globally. The sweet Primitivo di Manduria Dolce Naturale became Puglia's first DOCG in 2011, requiring 100 percent Primitivo and at least 50 grams per liter of residual sugar from on-vine drying. California Zinfandel carries no equivalent legal minimum varietal content beyond the standard US requirement of 75 percent for a varietal label, though US regulations require Zinfandel and Primitivo to be labeled separately.

• Croatia: Tribidrag/Crljenak Kaštelanski recognized as an authenticated indigenous Croatian variety; cultivated primarily in Dalmatia including Kaštela, Hvar, Brač, Pelješac, and Omiš
• Italy: Primitivo di Manduria DOC (since 1974) mandates minimum 85 percent Primitivo, 13.5 percent ABV minimum for dry style, 24 months aging for Riserva (9 months in wood, 14 percent ABV minimum)
• Italy: Primitivo di Manduria Dolce Naturale DOCG (since 2011) requires 100 percent Primitivo, on-vine drying, minimum 50 g/L residual sugar and 16 percent potential alcohol
• USA: Federal regulations require Zinfandel and Primitivo to be labeled separately; minimum 75 percent varietal content applies for AVA-designated Zinfandel labels; no legally defined 'Old Vine' standard exists at the federal level

The discovery transformed Kaštela into a wine heritage destination, linking the village's viticultural history to Split's nearby UNESCO-listed Diocletian's Palace. Visitors can taste Crljenak Kaštelanski from family cellars such as Bedalov and Radunić, which sit on the sites where the last surviving vines were found. Broader Dalmatian wine tourism connects Kaštela to producing islands including Hvar, Brač, and the Pelješac peninsula. In California, Dry Creek Valley's old-vine Zinfandel heritage is accessible through tasting rooms along Lytton Springs Road, while Lodi's Wine and Visitor Center documents the region's pre-Prohibition vine heritage. In Puglia, the town of Manduria anchors the Primitivo wine route, where ancient alberello vineyards and local cuisine provide a rich backdrop for tasting.

• Kaštela, Croatia: family cellars in Kaštel Novi and surrounding villages offer Crljenak Kaštelanski tastings near the sites where the original nine surviving vines were discovered in 2001
• Dalmatia wine routes: connect Kaštela with producing islands Hvar, Brač, and the Pelješac peninsula, where over two dozen wineries now produce Crljenak Kaštelanski or Tribidrag
• California: Dry Creek Valley offers direct access to Lytton Springs and Geyserville old-vine sites; Lodi's heritage vineyards, some with vines planted in the 1880s, are accessible through the Lodi Wine and Visitor Center
• Puglia: Manduria and surrounding Salento towns host harvest festivals each autumn centered on Primitivo, with ancient alberello vineyards alongside olive groves and pairings with local orecchiette, aged Apulian pecorino, and horse meat stews