For many diners, the arrival of a chocolate dessert is a cue to push aside the goblet of pinot noir. And, unless you are an aficionado of sweet wines or fortified wines like port, the options seem limited to liqueurs, coffee or water.

But when I began looking into the flavor components of wine vs. chocolate, I discovered that several affinities exist - and some of them are quite delicious. It has to do with the biochemical profiles of each, and how they interact on the palate.

For example, think of the flavors we do perceive in wine: berries, pears, cherries, plums and vanilla, among others. And what gives them vibrancy and structure? Acid and astringency (or tannin).

It is somewhat the same with chocolate, even more apparent as artisanal producers craft less-sweet and more varied creations. It's not uncommon today for a chocolatier to blend beans from several different countries, in the manner of winemakers blending grapes from different vineyards.

So if you are pondering what to drink when that Gibraltar of flourless chocolate cake arrives at the table - or if you opt to lie back at home with carry-in pizza and a floorboard-size plank of Lindt semisweet, here is a primer.

First, consider the type of chocolate, which is classified according to its percentage of chocolate "liquor," a term that refers to the sludgelike mass left after grinding treated cocoa beans. Major categories are:

Unsweetened: Also known as "bitter" or "baking" chocolate, this is pure liquor and is confined to cooking.

Bittersweet: The FDA requires this to be 35 percent pure liquor, although most bars found in stores contain at least 50 percent. The sugar content varies. It typically has a sharp and peppery edge that is offset by a relatively small dose of sugar.

Semisweet or dark chocolate: A bar of this can contain 30 percent liquor or more, and is blended with sugar, cocoa butter, vanilla and an emulsifier. The bitterness is less pronounced owing to the high sugar level. Most commonly, this is what people secrete in their work cubicles when they should be eating an apple.

Milk chocolate: Most valentine hearts are sculpted from this. About 10 percent liquor, it is fleshed out with condensed milk or dry milk solids, and butterfat, which gives it a waxy appearance. No bitterness.

White chocolate: Devoid of chocolate liquor. Devoid of flavor, too, other than sugar. It's essentially cocoa butter and milk solids. Nevertheless, it is in demand.

The first person I turned to for guidance on the chocolate and wine question was John Scharffenberger, cofounder of the artisanal chocolate company Scharffen Berger, in Berkeley, Calif. (now owned by the Hershey Co.), and previously a West Coast winemaker.

"There's a huge amount in common between wine and chocolate," he said. "In fact, you can learn a lot about wine by studying the fruit essences and acids and tannins. And it's a lot of fun."

Scharffenberger conducts wine and chocolate seminars around the country and has produced a video on the subject (see www.AllChocolate.com).

As a rule, the more bitter the chocolate, the fruitier and softer the wine (and the lower the tannins) to accompany it. Bitter chocolate and harsh tannic wines "do not make good cellmates," notes Mark Cochard, who teaches wine and chocolate classes at Chaddsford Winery in the Brandywine Valley. "If two similar sensations like that clash, it's unpleasant on the palate."

Cochard will be conducting wine and chocolate classes with Christopher Curtin, owner of Éclat Chocolates in West Chester, for the rest of the month.

Bittersweet chocolate, whether consumed in bar form or in a dessert, allows the widest range of wine pairings because it strikes a pleasing balance between astringency and sugar.

Juicy red wines like syrah (called shiraz in Australia) profit from a kick of sharp cocoa, too. Similarly, consider low-tannin zinfandels, pinot noirs and merlots. Supple Burgundian reds are custom-made, as are plump barbarescos from Italy. Then there is the plethora of simple, easy-drinking reds gushing north from the so-called New World. (I will address sweet and fortified wines later).

Semisweet, or dark, chocolate presents another diverting challenge. Because its astringency is somewhat masked by sugar, a complementary wine should contribute structure.

That translates to slightly tannic wines. Two that come immediately to mind are young French-style cabernet sauvignons and reds from the Rioja and Navarra regions of Spain. Riojas, in particular, can be marvelous, as they are generous with essences of vanilla, toasty oak, leather, and, yes, dark chocolate. Young Italian Barolos and some Australian cabernet sauvignons can be added to the barrel. Also worth exploring are certain frisky young California zinfandels (3 to 6 years).

Dark chocolate, naturally, requires a sturdy wooden crutch. Many of the wines recommended above can work well here. Again, stick with recent vintages in which the tannin is still in play. To this list you could add, from France, cabernet sauvignons, and the spicy and high-alcohol petite verdots from Bordeaux. Lightly oaked reds from the Pacific Northwest have the goods as well.

When we consider milk chocolate, the going gets slippery. Since we can't go further down the tannin highway without chewing on the barrels, we have two other areas of exploration. Several experts promoted dry reds, others dry whites like muscadet and sauvignon blanc.

"In Switzerland," explained Albert A. Lauber V, chocolatier at Neuchatel Chocolates, based in Oxford, Pa., "when we had a very sweet dessert, sometimes a dry white wine held a nice contrast."

Virtually every connoisseur interviewed passionately maintained that the best match with any type of chocolate, bitter to sweet, is port.

"Americans don't drink a lot of port, but it is so warm and woody and complex - it's perfect," gushed wine-and-chocolate maker Scharffenberger.

Port, a sweet, barrel-aged fortified wine from Portugal, comes in many guises and price ranges, with rare vintages fetching hundreds of dollars. For about $30 you can find good tawny port (named for its color) from well-known houses (Sandeman, Cockburn, Dow's, and Fonseca). Madeira, from the Portuguese islands of the same name, is excellent as well.

Similarly, dessert wines can be fetching dates with all types of chocolates. It's really a matter of your affinities.

Does your heart race in the presence of a ripe apricot? Try a Malvasia di Lipari from the Italian island of the same name. For a marvelous distillation of honey and raisins, ask your wine merchant about late-harvest whites or reds - the term connotes grapes left on the vine to shrivel and intensify.

So, if you are fortunate enough to receive a box of quality chocolates - or any chocolates, I suppose, if romance is the objective - keep in mind Forrest Gump's dictum: You never know what lies ahead, so keep an open mind.