Once you decide to make hot chocolate from scratch, you have to select a chocolate from a dizzying array of options--unsweetened, bittersweet, semisweet, sweet dark, dark and milk.

The categories are labeled according to the proportion of cocoa liquor (or mass, as they say in Britain) to sugar. Unsweetened chocolate is 100 percent cocoa mass (and no sugar); bittersweet chocolates hover around 70 percent; semisweet is slightly sweeter; and milk chocolate is about 50 percent cocoa mass.

Most hot chocolate recipes call for either bittersweet or semisweet chocolate, which are largely interchangeable. We tested the following bittersweet and semisweet chocolates, all available locally, in the same hot chocolate recipe for taste, texture and appearance.

Although we enjoy many of these chocolate bars for nibbling and baking, their ability to hold up in hot chocolate was far from equal. They are listed in order of preference; prices are approximate.

Whole Foods Certified Organic Dark Chocolate (50 percent cocoa mass; $1.99 for 3.5 ounces) made exactly what you would expect in a mug of hot chocolate. Sweet but not too sweet, this was very drinkable. The mellow flavor was undoubtedly due to the low percentage of cocoa solids, similar to that of milk chocolate but not generally labeled as "dark."

Valrhona Dark Bittersweet Chocolate (71 percent cocoa mass; $4.75 for 3.5 ounces) made a very velvety, adult hot chocolate. This would appeal to European hot chocolate drinkers with its bitter overtones, which were too pronounced for the milk chocolate lovers but grew on us with each sip.

Scharffen Berger Pure Dark Chocolate (70 percent cocoa mass; about $4.25 for 3 ounces) was a little too dark and too grainy for our tastes, with bitter overtones.

Nestle Semi-Sweet Chocolate Chips ($2.50 for 12 ounces) would work when it's the only chocolate you have in the pantry. But be prepared for very rich, slightly goopy results with a grainy texture.

Ghiradelli Semi-Sweet Chocolate ($2.55 for 4 ounces) had an overwhelmingly artificial, not chocolate, flavor.

Lindt Excellence Dark Chocolate (70 percent cocoa mass; $2.75 for 3.5 ounces) made us reflect on the fact that chocolate is said to be comprised of more than 500 flavors; this chocolate, when used in hot chocolate, was stuck on one not very pleasant note.