A brief glance at Hachette's French wine guide reveals that, with rare exceptions, the vignerons of Bordeaux and Burgundy receive visitors only sur rendez-vous—by appointment. Even if you're lucky enough to secure a 15-minute slot, the way you'll be treated and the wines you'll taste can vary widely. The surest way to have a great experience is to employ a well-connected local guide. That's true in wine regions around the world, where the best guides open doors that might otherwise be closed. Here, six guides who hold the keys.
Guide Carla Giomi, who has been sommelier for three European princes.
Company ABC Tours, based in San Gimignano.
Tours Customized trips for up to six people to top Chianti and Brunello di Montalcino estates.
Winery Highlights Smaller Brunello di Montalcino producers like La Fornace, a tiny, buzzworthy estate run by 32-year-old Fabio Giannetti, as well as big name estates like Ornellaia, Castello di Ama and Isole e Olena.
Unforgettable Moment Visiting Chianti butcher Antica Macellerie Falorni and Montalcino cheesemaker Fattoria dei Barbi to taste the timeless connection between Tuscan wine and food.
Hotel Highlight The three-bedroom apartment above the cellars at La Velona, which has a fireplace and a gorgeous view of the Orcia Valley.
Details $700 for four people per day includes tastings, but not meals or accommodations. 011-39-347-905-24-47 or abcwine.it.
Guide Guillermo Donnerstag, the winemaker at Mendoza's up-and-coming Familia Marguery.
Company Limitless Argentina, based in Buenos Aires.
Tours Itineraries for up to eight people in the Mendoza region, known for the Malbec grape.
Winery Highlights Bodega Catena Zapata, where owner Nicolás Catena makes some of Mendoza's finest wine; Ruca Malen, a winery producing sensational Malbec; Monteviejo, where star French consultant Michel Rolland crafts Clos de los Siete.
Unforgettable Moment A stop at Dominio del Plata, where talented winemaker Susana Balbo explains her high-flying wines.
Hotel Highlight The extraordinary new Cavas Wine Lodge, a sleek spa-hotel in the Andes foothills.
Details $450 for two people per day includes tastings and lunch, but not accommodations. 202-536-5812 or limitlessargentina.com.
Guide Sommelier Lauriann Greene-Sollin, who devoted herself to French wine after meeting Jean-Pierre Sollin—another top guide, now her husband.
Company French Wine Explorers, based in Coconut Creek, Florida.
Tours Visits to producers in the Côte d'Or, including grand cru estates in the Côte de Beaune.
Winery Highlights Domaine Bertagna, a small estate in the medieval walled vineyard of Clos de Vougeot; Clos de Tart, the 18-acre grand cru in Morey-Saint-Denis.
Unforgettable Moment Stopping at the Beaune merchant Camille Giroud, co-owned by Ann Colgin of the cult California vineyard Colgin, for an illuminating tasting comparing young Pommard and Gevrey-Chambertin to much older vintages.
Hotel Highlight Hôtel Le Cep, in Beaune, a luxuriously restored 14th-century inn with antique-filled rooms.
Details $4,395 per person for five days includes tastings, most meals and accommodations. 877-261-1500 or wine-tours-france.com.
Guide James Lawther, a British-born Bordeaux resident, wine writer for Decanter magazine and Master of Wine.
Company In Touch Travel, based in Seattle.
Tours Custom itineraries in the Médoc, Graves, St-Émilion, Pomerol and Sauternes.
Winery Highlights Grand cru estates such as Cheval Blanc, L'Angélus, Latour, Margaux, Leoville Las-Cases and tiny cult favorites such as Valandraud and Le Pin. These châteaus have little incentive to accept visitors, which makes Lawther's services especially valuable.
Unforgettable Moment Tasting great wines next to a 12th-century chapel, at Château Ausone, one of the top two estates in St-Émilion.
Hotel Highlight Château Cordeillan-Bages, in Pauillac, a 17th-century monastery converted into a Relais & Châteaux hotel with a Michelin two-star restaurant.
Details $1,000 per group of up to four people per day includes tastings and lunch but not transportation or accommodations. 866-396-5102 or intouchtravel.com.
Guide Wayne Donaldson, who has been leading wine tours around the Western Cape for 10 years.
Company Ocean & Vine Tours, based in Cape Town.
Tours Customized tours of the Cape's many wine regions, including Stellenbosch, Paarl, Constantia, Robertson, Walker Bay, Tulbagh and the Riebeek Valley.
Winery Highlights High-profile Stellenbosch wineries like Rustenberg, Thelema and Ernie Els (the eponymous venture from the local golf hero); lesser-known estates such as Pulpit Rock in the Riebeek Valley and rising star Groote Post in Darling Hills.
Unforgettable Moments Tasting Pinot Noir at Hamilton Russell, Africa's southernmost winery, then driving to the coast for whale-watching.
Hotel Highlight Rijk's in Tulbagh, a lakeside winery and hotel where some rooms have views of vineyards and the Witzenberg mountains.
Details $130 per person per day for groups of two includes tastings, but not meals or accommodations. 011-27-82-900-6999 or prowinetours.co.za.
Guide Mary Anne Kennedy, an Adelaide native, has been leading wine tours for 16 years.
Company A Taste of South Australia, based in Adelaide.
Tours Personalized itineraries through South Australia's wine regions, including Barossa Valley, Clare Valley, Adelaide Hills, McLaren Vale and Coonawarra, with "Icon" tours of each area's most sought-after wines.
Winery Highlights Up-and-comer Clarendon Hills in Blewitt Springs; d'Arenberg in McLaren Vale, famous for "The Dead Arm" Shiraz; Wendouree in Clare Valley, a winery with a cult following for its Shiraz; Henschke, in the Barossa, producer of the celebrated Hill of Grace Shiraz.
Unforgettable Moments Tasting the 1998 vintage of Penfolds Grange, Australia's most legendary Shiraz; flying in a prop plane to a remote corner of Coonawarra to taste barrel samples of Wynns John Riddoch Cabernet Sauvignon, one of the region's most famous wines.
Hotel Highlight Thorn Park Country House in Clare Valley, a secluded, antique-filled, iron-roofed 1850s homestead whose owners are wonderful hosts.
Details From $750 per person per day includes tastings, lunch and accommodations. 011-61-8-8371-3553 or tastesa.com.au.
Robert Joseph's latest book is The Wine Travel Guide to the World.