Anyone who has uncorked a carefully stored 20-year-old Dominus or 30-year-old Ridge Monte Bello knows that California wine can age well. The bouquet is fascinating and evolved, the palate retains some freshness, and the mouthfeel has turned silky\u2014just what\u2019s supposed to happen as a great wine matures.\r\n\r\nLast year, Liv-ex, the global marketplace for the wine trade, introduced its California 50 Index, and sales of the top collectibles have surged at Sotheby\u2019s in New York City, Hart Davis Hart Wine Co. in Chicago and on the San Francisco-based Vinfolio trading and cellar-management platform. This means that now is an ideal time to collect the cr\u00e8me de la cr\u00e8me of California wines, those with proven ability to improve over time in both enjoyment and worth.\r\n\r\nWith that in mind, we gathered secondary market data on dozens of wines to calculate the most collectible California bottlings today. We considered wines whose first vintage was at least 15 years ago, those widely regarded to hold or improve in quality with time, ones traded most frequently in the U.S. and abroad, and bottlings with high price appreciation, calculated by comparing release prices and future resale figures compiled by Liv-ex.\r\n\r\nRead on to discover the state\u2019s top 10 blue-chip bottles, ranked by the average rate of their six-year appreciation.\r\n\r\n\r\n1.\u00a0 Screaming Eagle Cabernet Sauvignon\r\nAppellation: Oakville\r\nFirst Vintage: 1992\r\nCurrent Release: 2016, $2,500, 780 cases\r\nCurrent Winemaker: Nick Gislason\r\nAverage Recent Market Prices: 2010 - $3,510; 2005 - $3,310; 1995 - $3,750\r\nAverage Six-Year Appreciation: 103%\r\n\r\nScreaming Eagle is the most collectible California wine, based on its secondary market value and average price appreciation. The story of its beginning has been told many times. Real estate agent Jean Phillips bought a vineyard along the eastern edge of Napa Valley\u2019s Oakville appellation in 1986. It turned out to have a small block of exceptional Cabernet Sauvignon. She later hired Heidi Barrett as her first winemaker, and the wine was launched with a memorable name and striking bottle. Since then, new owners have come in, vineyards have expanded and production has increased from around 200 cases to as many as 800 cases per year, and yet the glow of this silky, polished and beautifully concentrated wine has never diminished.\r\n2. Dominus\r\nAppellation: Napa Valley\r\nFirst Vintage: 1983\r\nCurrent Release: 2016, $299, 5,500 cases\r\nCurrent Winemaker: Tod Mostero\r\nAverage Recent Market Prices: 2010 - $295; 2005 - $200; 1995 - $185\r\nAverage Six-Year Appreciation: 93%\r\n\r\nChristian Moueix belongs to a Bordeaux wine merchant family whose assets long included Ch\u00e2teau P\u00e9trus in Pomerol. He first fell in love with Napa Valley as a grad student studying enology at the University of California, Davis, during the 1960s. Dominus Estate, a minimalist stone winery in the historic Napanook vineyard in Yountville, is his monument to that moment. The brand has consistently released one of the most long-lived and classically styled wines in California, mostly from Cabernet Sauvignon grapes. Collectors have invested in Dominus for a generation, but it\u2019s recently appreciated in value almost as fast as Screaming Eagle.\r\n3. Scarecrow Cabernet Sauvignon\r\nAppellation: Rutherford\r\nFirst Vintage: 2003\r\nCurrent Release: 2016, $400, 2,000 cases\r\nCurrent Winemaker: Celia Welch\r\nAverage Recent Market Prices: 2010 - $605; 2005 - $650\r\nAverage Six-Year Appreciation: 80%\r\n\r\nIn the early 2000s, photographer Brett Lopez acquired a home and vineyard property adjacent to Inglenook on the west side of the famed Rutherford appellation of Napa Valley. Planted to Cabernet Sauvignon in 1945, it had belonged to his grandfather, J.J. Cohn, who, as the chief of production for MGM, had been instrumental in making The Wizard of Oz. When Lopez began to make wine from these vines stretching toward the mountains in 2003, he borrowed the name of one of the bravest characters from his grandfather\u2019s classic. Previously, the Scarecrow estate supplied grapes for classic Cabernet Sauvignons from Inglenook, Niebaum-Coppola, Opus One and Joseph Phelps Insignia.\r\n\r\n\r\n4. Opus One\r\nAppellation: Napa Valley\r\nFirst Vintage: 1979\r\nCurrent Release: 2016, $365, 21,900 cases\r\nCurrent Winemaker: Michael Silacci\r\nAverage Recent Market Prices: 2010 - $475; 2005 - $500; 1995 - $450\r\nAverage Six-Year Appreciation: 71%\r\n\r\nNapa Valley producer Opus One is a French-American wine estate located in Oakville. It was founded by two larger-than-life figures in 20th-century winemaking, local icon Robert Mondavi and Baron Philippe de Rothschild of Bordeaux, who came together in pursuit of a classic, ageworthy red wine from Napa grapes through traditional French techniques. While Rothschild owned the first-growth Ch\u00e2teau Mouton-Rothschild and brought instant celebrity to the venture, the wine wouldn\u2019t have become such a success if it didn\u2019t live up to that hype. The duo built a monumental winery, and, within only a few years, their enologists perfected the wine\u2019s layered, sculpted style. Eventually, Opus One became the first American wine sold through n\u00e9gociants on La Place de Bordeaux alongside the elite classified growths.\r\n5. Ridge Monte Bello\r\nAppellation: Santa Cruz Mountains\r\nFirst Vintage: 1962\r\nCurrent Release: 2016, $225, 5,150 cases\r\nCurrent Winemaker: Eric Baugher\r\nAverage Recent Market Prices: 2010 - $195; 2005 - $265; 1995 - $350\r\nAverage Six-Year Appreciation: 67%\r\n\r\nRidge Monte Bello has the longest track record of California\u2019s top collectibles, and it\u2019s the only one made outside Napa Valley. The firmly structured, intricate and famously long-aging wine grows on Ridge Vineyard\u2019s home property situated between 1,300 and 2,700 feet above sea level, where it sits above the high-tech campuses of Silicon Valley and catches cool breezes from the Pacific. The 2016 was made from 72% Cabernet Sauvignon blended with Merlot, Petit Verdot and Cabernet Franc. After a period of lower recognition, Monte Bello\u2019s value has begun to appreciate quickly. Meanwhile, bottlings at peak maturity and those from fascinating vintages from the 1980s and 1990s remain available at lower prices than new releases.\r\n6. Harlan Estate\r\nAppellation: Napa Valley\r\nFirst Vintage: 1990\r\nCurrent Release: 2015, $1,500, 1,800 cases\r\nCurrent Winemaker: Cory Empting\r\nAverage Recent Market Prices: 2010 - $1,000; 2005 - $750; 1995 - $850\r\nAverage Six-Year Appreciation: 64%\r\n\r\nWilliam Harlan, a former real-estate developer, built Harlan Estate from the ground up. He envisioned a classic estate winery that could grow and produce wines on the same site, one with the potential to last for many generations. In 1984, he chose a beautiful hilly location in Napa Valley\u2019s Oakville district that overlooked famous properties like Martha\u2019s Vineyard and To Kalon, and, having previously been an owner of Merryvale Vineyards, tapped former employee Bob Levy to be his founding winemaker. Harlan Estate\u2019s signature red became a classic from its first vintage in 1990, with its bold Cabernet Sauvignon flavors, massive structure and slow aging curve keeping it near the top of today\u2019s collectors\u2019 wish lists. Note that older, drinkable vintages can be about half\u00a0 the price of new ones.\r\n\r\n\r\n7. Colgin IX Estate Red Wine\r\nAppellation: Napa Valley\r\nFirst Vintage: 2002\r\nCurrent Release: 2016, $650, 1,800 cases\r\nCurrent Winemaker: Allison Tauziet\r\nAverage Recent Market Prices: 2010 - $550; 2005 - $400\r\nAverage Six-Year Appreciation: 63%\r\n\r\nArt collector and philanthropist Ann Colgin and her then-husband, Fred Schrader, made their first vintage from the Herb Lamb Vineyard in 1992. Offerings from the small winery, of which luxury goods group LVMH purchased a 60% stake in 2017, have evolved over time. Today\u2019s most collectible item is the IX Estate Red Wine, an inviting and richly textured blend of Cabernet Sauvignon, Merlot, Cabernet Franc and Petit Verdot that debuted for the 2002 vintage. The grapes are grown in the Pritchard Hill area at elevations ranging from 1,150\u20131,350 feet, in rugged terrain along the eastern rim of Napa Valley. Colgin\u2019s Cariad red wine, which launched in 1999, is a close runner-up in collectability.\r\n8. Joseph Phelps Insignia\r\nAppellation: Napa Valley\r\nFirst Vintage: 1974\r\nCurrent Release: 2016, $300, 13,400 cases\r\nCurrent Winemaker: Ashley Hepworth\r\nAverage Recent Market Prices: 2010 - $215; 2005 - $225; 1995 - $215\r\nAverage Six-Year Appreciation: 53%\r\n\r\nJoseph Phelps Insignia was the first of many high-end red wines in the modern era to carry a proprietary name rather than a varietal label. Though the initial idea was to allow for flexibility to make the wine from any varietal, founder Joseph Phelps and then-winemaker Walter Schug would soon focus Insignia on a blend made from Bordeaux varieties. Eventually, the grapes came mostly from Phelps\u2019 own vineyards, especially those from the cooler parts of Napa Valley, like the Stags Leap District, Oak Knoll and the south of the valley. Recent vintages stress Cabernet Sauvignon and show vivid fruit character complemented by generous oak spices. Insignia ages well, and its price stays near the low end of Napa collectibles, due in part to its relatively large production.\r\n\r\n\r\n9. Paul Hobbs Beckstoffer Dr. Crane Vineyard Cabernet Sauvignon\r\nAppellation: Napa Valley\r\nFirst Vintage: 2003\r\nCurrent Release: 2015, $285, 815 cases\r\nCurrent Winemaker: Paul Hobbs\r\nAverage Recent Market Prices: 2010 - $350; 2005 - $345\r\nAverage Six-Year Appreciation: 50%\r\n\r\nSonoma County-based winemaker Paul Hobbs is adept at both Russian River Valley Chardonnay and Argentine Malbec. But it\u2019s his Napa Valley-grown Cabernet Sauvignon from a St. Helena vineyard first planted in 1858 that\u2019s become his most collectible wine. The warm, flat site known as Dr. Crane Vineyard has been owned and managed by Beckstoffer Vineyards since 1997, and it features deep, gravelly loam soil well-suited to the four clones of Cabernet that grow there. Hobbs touts the wine\u2019s powerful aromatics, while others remark on its silky tannins. Collectors have shown their intense interest, as average prices have surged 50% since 2013.\r\n10. Robert Mondavi To Kalon Reserve Cabernet Sauvignon\r\nAppellation: Oakville\r\nFirst Vintage: 1971\r\nCurrent Release: 2016, $175, 8,829 cases\r\nCurrent Winemaker: Genevi\u00e8ve Janssens\r\nAverage Recent Market Prices: 2010 - $135; 2005 - $125; 1995 - $85\r\nAverage Six-Year Appreciation: 50%\r\n\r\nWith the least expensive release price on this most-collectible list, the Robert Mondavi Reserve Cabernet is an ideal starting place for a wine collection. Mondavi began to make Cabernet in the winery\u2019s inaugural vintage of 1966, and the \u201cReserve\u201d term was started with the 1971 vintage. Grapes from the famed and subdivided To Kalon property, on which the winery was built, have been included from the beginning. However, it\u2019s only been called out on the label since 2011. While it\u2019s aged in all-new French barrels each year, the winery has refrained from crafting the wine with too much ripeness, and it retains a distinctive sage and currant character that sets it apart. Some beautifully mature older vintages can be had for half the price of new releases.\r\n\r\n\r\nFive Musts for Successful Cellaring\r\nWhether you choose to enjoy or resell, collectible wine is an investment. To protect that investment, it\u2019s necessary to store your wine under the best conditions. These are the five conditions to ensure proper cellaring.\r\n\r\n1. Keep it cool. Storage at or near 55\u02daF is optimal to ensure slow, patient maturation of the wine.\r\n\r\n2. Mind the moisture. If the space is too humid, the labels can mildew. Too dry? Air space in the bottles (called \u201cullage\u201d) will increase too fast over time.\r\n\r\n3. Go dark. Light can penetrate clear glass wine bottles and affect the wine.\r\n\r\n4. Do not disturb. Don\u2019t store bottles where strong vibrations or frequent changes of position will stir the wine inside.\r\n\r\n5. Take note. Keep accurate records of your purchases to show good provenance for eventual resale, or simply to remind yourself just how well you planned.\r\nWhere to Score Old Beauties\r\nThe best way to buy new vintages of the top collectibles is to sign up for direct purchases via winery websites. Be warned, however, that this can involve spending years on a waiting list.\r\n\r\nMore immediate gratification can be had by bidding on older vintages at the U.S. auction houses of Sotheby\u2019s, Zachys, Christie\u2019s and Acker Merrall & Condit in New York City; Hart Davis Hart in Chicago; and Heritage, Bonhams, Spectrum and Zachys in California. Virtual bidding is another option, and WineBid and Heritage Auctions conduct online auctions.\r\n\r\nCollectors buy, store and sell wines through Vinfolio, while Liv-ex is a unique resource for the global wine trade that allows them to price, source and sell wine . And Wine-Searcher gives instant, specific retail prices on virtually any wine, as well as links to the stores that sell it.\r\n\r\nFor past vintages of top collectibles, Wine.com often has a few in stock. Finally, most major U.S. cities have at least one or two fine wine shops that carry California collectibles, so it\u2019s smart to meet your local retailers, too.