Centuries ago, Madeira’s location on trade routes to the New World helped introduce its fortified wines to new markets, including colonial America. (Madeira Wine Co.)

America once had a love affair with Madeira. Our Founding Fathers hoisted glasses of this fortified wine to toast the signing of the Declaration of Independence, and it was a favorite tipple at dinner tables throughout the young nation.

“About 75 percent of all wine consumed in the colonies in the 18th century was Madeira,” says Chris Blandy, 36, seventh-generation chief executive of the wine company that carries his family’s name. “Today, Madeira unfortunately has the image of cooking wine.”

There’s nothing wrong with filet mignon in a Madeira sauce, of course. But over the past decade or so, Madeira sales in the United States have grown steadily, up to about 12,000 cases a year, Blandy says. That’s still a niche wine, but as U.S. consumers explore wines from around the world, they have discovered Madeira again.

Blandy was in back in Washington recently to introduce new releases of vintage Blandy’s dating to the 1960s. He lived here from 2003 to 2007, working at the Willard InterContinental hotel before joining the family firm that was established in 1811.

Chris Blandy, 36, is the seventh-generation chief executive of his family firm, established in 1811. (Madeira Wine Co.)

The Portuguese island of Madeira boasts picturesque vineyard views. (Madeira Wine Co.)

Madeira is in some respects similar to port; in others, more like sherry. It hails from the Portuguese island of Madeira, about 500 miles off the coast of North Africa. The island’s location on trade routes to the New World fueled its early popularity here. Large casks of it were used as ballast on trade ships, and the wines actually tasted better after their ocean voyage.

Here’s a three-point primer on Madeira:

■ There are four main styles, named for the grapes used to make the wines and ranging from dry to sweet: sercial, verdelho, boal (or bual) and malmsey (an old British word for malvasia). Sercial can be searingly dry, with an appealing saline character and a flavor of toasted almonds: Think of a fino sherry on steroids. Even the sweeter boal and malmsey wines are not cloying, their sugar balanced by acidity. Don’t limit these to dessert; their rich umami character makes them ideal for hearty, savory soups or stews.

■ Within these four styles there are grades of quality: Five-year-old, 10-year-old, colheita and vintage. The first two are multi-vintage blends averaging those ages. Colheitas are vintage dated, from a single year, and aged less than 20 years in large oak casks. Vintage Madeiras have aged in cask at least 20 years, often much longer, before bottling.

As examples, the new Blandy’s releases — a 1979 verdelho, a 1977 terrantez (the most exotic of the lot, made with a grape that unfortunately is vanishing from Madeira’s vineyards), a 1975 sercial and a 1966 bual — were bottled this past November.

■ What accounts for the difference in quality? Time. Each year the wines spend in cask, a little volume is lost to evaporation, intensifying the flavors and aromas. And unlike any other type of wine, Madeira is indestructible: Once opened, it will stay delicious indefinitely, even without refrigeration. (I’ve never succeeded in verifying that, to be honest. Once opened in my house, Madeira evaporates rather quickly.)

“Up to the 10-year-olds, be as wild as you want with food pairings,” Blandy says. “The older, vintage-dated Madeiras have enough complexity that you should drink them by themselves. These are wines of reflection.”

At Plume, the luxury restaurant in Washington’s Jefferson Hotel, diners often contemplate the history held in their glass, says Jennifer Knowles, the hotel’s beverage director. Knowles inherited and has expanded one of the strongest Madeira selections in the country.

Sipping a vintage Madeira from the 19th century, “people will pull out their phones and look up what was happening that year and have their minds blown,” Knowles says.

Indicating the new Blandy’s releases from the 1960s and 1970s, she adds: “These wines are contemporaries. They’re anniversary or birth-year wines. People have their own stories to tell.”