As borders come down and international travel is made easier, so, too, do Americans benefit from expanded import/export trade.

Wines from heretofore unknown grapegrowing regions of the world are turning up on retail shelves daily, some even finding their way into chain supermarkets.

While Spain’s best known wine exports are its outstanding reds and fruity cavas, there are several outstanding whites getting deserved attention these days as well.

One of them is a delightful aromatic wine from Rueda, a region northwest of Madrid and just to the south of the Duero River.

Verdejo is one of Spain’s exceptional white wines, a soft, racy mouthful that is as good a quaffer as it is accompaniment to everything from briny oysters to Kung Pao chicken. As equally full-bodied as its regional sister, albariño, verdejo has aromatics reminiscent of sauvignon blanc grown in warmer climes. 

It’s believed that the verdejo grape originated in North Africa, and was spread to Rueda about the 11th century, possibly by Mozarabs, descendants of the ancient Hispano-Romano-Gothic Christians who became Arabic speakers under Islamic rule.

For centuries, verdejo was generally used to make a strongly oxidized, sherry-like wine. In the 1970s, the winemaking company Marqués de Riscal began to develop a fresher style of white wine based on verdejo with the help of French enologist Émile Peynaud, credited with revolutionizing French winemaking in the latter half of the 20th century.

As a consequence, in 1980 white wines from the Rueda region were recognized by a Denominación de Origen (D.O.). Wines labeled “Rueda” must contain 50 percent verdejo; the remainder is typically sauvignon blanc or viura (known as macabeo in Catalunya). Wines designated “Rueda Verdejo” must contain 85 percent verdejo, but more often than not are 100 percent verdejo.

Named for the unprepossessing town that straddles the main road from Madrid to León, Rueda produces very little amounts of red, rosé and sparkling wines as well. In addition to verdejo, sauvignon blanc is also produced by some cellars, after being introduced to the region in the 1980s by Marqués de Riscal. Some top-flight sauvignon blancs have been produced, including one from the Lurton family of Bordeaux.

But verdejo is king here, accounting for as much as 95 percent of the region’s annual production, according to Cristina Manzano González, foreign trade specialist with the Rueda D.O. organization.

Several producers, along with representatives of the Rueda trade group, set up a special tasting recently at the acclaimed Catalan restaurant, B44, in San Francisco. Here are our impressions of some of the dozen or so sampled:

Sitios de Bodega Con Class Verdejo 2008: A fresh herbal nose with grassy and grapefruit notes, this is a blend of verdejo, viura and sauvignon blanc. It’s a light-bodied white, delicate really, with pronounced citrus on the tongue and a bright finish. Should go well with cheese and, believe it or not, asparagus.

Sitios de Bodega Con Class Rueda Verdejo 2008: It has both the color and aroma of hay, with lemon and grapefruit vying for attention on the tongue. It has a wonderfully refreshing lemon finish, and should do well with triple cream cheese.

Marqués de Irún Verdejo 2008: A crisp grapefruity wine that has quite an herbal/hay nose, this one is certainly ideal for a pile of freshly shucked oysters. Because a squirt of lemon coats the palate,  it might do well for a briny paella chock full of shellfish.

Viñedos de Nieva Blanco Nieva Rueda Verdejo 2008: A blend of new and old verdejo vines (70/30, respectively), this is an exceptional wine. An elegant white with aromas of citrus, thyme and tarragon, it’s a balanced mouthful of lemon with a spritz of key lime on the finish. A wonderful lively, fresh wine that could be served with just about anything.

Viñedos de Nieva Pie Franco Rueda Verdejo 2008: The jewel of the house, made from 100-year-old vines. This enterprising, relatively new winery (launched but 20 years ago) shows it knows how to make outstanding wine, with both verdejo and sauvignon blanc entries. Here is an inviting citrus and tarragon nose with a well-balanced follow-through of lemon and sage, a little mineral and lemon curd on the long finish.

Viñedos de Nieva Blanco Nieva Sauvignon 2008: Pleasant grassy nose introduces this well-balanced, very tasty Spanish interpretation — lots of citrus with a slightly sweet tropical finish. A well balanced wine that should pair with any number of dishes.

All of the wines tasted were in the $10 to $18 range, offering a lot of bang for the buck. Verdejo isn’t that easy to come by in the Napa Valley. Check with Dan Dawson at Back Room Wines in Napa as he’ll  be able to point you in the right direction. While he doesn’t have any of the aforementioned wines, he does have a Valdelainos Verdejo 2008 ($14), which he says has “intense zing, with green apple, grapefruit and citrus zest flavors.”

Tired of cookie cutter chardonnays? Then think Spain, and pop the cork on a refreshing verdejo.

If you happen to be in San Francisco, try K&L Wine Merchants at 638 Fourth St., or their store in Redwood City. You might want to check online or give a call if you’re making a special trip. From this taster’s perspective, however, a special trip will be worth your while.