Chocolate has been called the food of the Gods, and as Karl Petzke and Sara Slavin note in Chocolate, A Sweet Indulgence (Chronicle Books, 1997) "The craving for chocolate is physical, arising out of the desire for its uniquely dark, slightly bitter, rich taste. But the craving is also emotional for chocolate symbolizes, as does no other food, luxury, comfort, sensuality, gratification and love."
Although chocolate may not actually be a true aphrodisiac it does contain theobromine, a mild relative of caffeine and magnesium, a component found in some tranquilizers, so it has the unique ability to simultaneously both pick you up and calm you down. In addition, it's said eating chocolate releases a chemical in your body similar to that which is produced when you're in love.
Despite the fact we've been consuming chocolate in copious quantities since the nineteenth century (although the Aztec emperor Montezuma was drinking it -- about 50 goblets a day -- centuries earlier) Americans don't win the prize for highest world wide chocolate consumption. No that distinction goes to the Swiss whose per capita consumption is a whopping 19 pounds a year. The Swiss are followed by the citizens of Norway, the United Kingdom, Belgium/Luxembourg, the Netherlands, Germany, Austria, Ireland, Denmark, Sweden -- and then the U.S.A. where every man, woman and child is said to munch down 9 pounds a year.
Chocolate is the most popular dessert flavoring around. But as you'll discover it's a long way from cocoa bean to chocolate bar. Detailing the process chocolate expert Elaine Gonzalez writes in The Art of Chocolate (Chronicle Books, 1998) "Chocolate is made from beans that grow inside the pods of the cacao trees, which flourish in hot, rainy climates within 20 degrees of the equator. Cocoa beans, as they are known in the United States, don't develop their distinctive chocolate color, flavor and aroma until they have been fermented, dried and carefully roasted to precise temperatures. The roasted beans are then shelled and cracked into small pieces called nibs. The nibs are then ground, producing a thick, semi-fluid mixture called chocolate liquor, the primary ingredient in all forms of chocolate, except white chocolate."
Because chocolate is so delicate to work with many cooks often find they have a problem melting it properly. Keep in mind that chocolate naturally melts just below body temperature, so applying direct heat, say atop a stove is apt to scotch it. Instead utilize a double boiler and melt it slowly in a heatproof bowl or pot set above a pan of simmering water, being careful both to stir frequently and make sure none of the water below or the condensation from the steam created leaches into the chocolate. You can also use a microwave oven to melt chocolate with good results, just be sure you stop it frequently to stir it. Generally when the chocolate appears melted about two-thirds of the way through, remove it from the microwave oven and continue to stir it until smooth. The residual heat contained in the melted chocolate will work to help melt the rest.
Unsweetened Chocolate is pure chocolate liquor, also known as bitter or baking chocolate. It's unadulterated chocolate: ground roasted chocolate beans with no other added ingredients imparts a strong, deep chocolate flavor in all the sweets you add it to. With the addition of sugar however it's used as the base for American style layer cakes, brownies, frostings and cookies.
Couverture or Coating Chocolate is a term used for cocoa butter rich chocolates of the highest quality. Popular brands of couverture used by professional pastry chefs and often sold in gourmet and specialty food stores include: Valrhona, Callabaut, Lindt, and Schraffen-Berger. These chocolates contain a high percentage of chocolate liquor (sometimes more than 70 percent) as well as cocoa butter, at least 32-39%, are very fluid when melted and have an excellent flavor. In fact, chocolate of this quality is often compared to tasting fine wine because subtleties in taste are often apparent, especially when you taste a variety of semisweet and bittersweet couvertures with different percentages of sugar and chocolate liquor.
Bittersweet Chocolate is chocolate liquor (or unsweetened chocolate) to which sugar, more cocoa butter, lecithin, and vanilla has been added. It has less sugar and more liquor than semisweet chocolate but the two are interchangeable in baking. The best quality bittersweet and semisweet chocolate is produced as couverture and many brands now print the percentage of chocolate liquor it contains on the package. The rule is the higher the percentage of liquor the more bittersweet the chocolate will be. Generally Europeans favor bittersweet chocolate and Americans opt for semisweet chocolate which has more sugar than bittersweet chocolate.
Sweet Chocolate is not as common today as it once was years ago. Developed by the American chocolate manufacturer, Baker's Chocolate, it is called for in a few recipes and can be found in most supermarkets.
White Chocolate isn't really considered chocolate at all due to the absence of chocolate liquor. Quality white chocolate however always contains cocoa butter. Be wary if you find white chocolate made with vegetable shortening and/or labeled "confectioners' coating" which pales in comparison -- taste wise -- to real white chocolate. And be especially careful when melting white chocolate which is particularly fragile.
Cocoa Powder, there are two types of unsweetened baking cocoa available: natural cocoa (like the sort produced by Hershey's and Nestle) and Dutch-process cocoa (such as the Hershey's European Style Cocoa and the Droste brand). Both are made by pulverizing, partially defatted chocolate liquor (unsweetened chocolate) removing nearly all their cocoa butter. Natural cocoa is light in color and somewhat acidic with a strong chocolate flavor. In baking use natural cocoa in recipes which call for baking soda (because it's an alkali). Combining the two creates a leavening action that allows the batter to rise during baking. Dutch-process cocoa has been processed with alkali to neutralize it's natural acidity so it's darker often with a reddish cast. Dutch cocoa is slightly milder in taste and deeper in color than natural cocoa. Use Dutch cocoa in recipes that call for baking powder as it's leavener. I also prefer to use Dutch process in recipes like truffles and tiramisu where the taste of the unsweetened cocoa powder plays an important role.
Sources: Chocolate facts and tips excerpted from article by Laurann Claridge, Chef and Food Talk Columnist of the Houston Chronicle, Houston, Texas USA. Chocolate Time Line excerpted from Chocolate, A Sweet Indulgence by Karl Petzke and Sara Slavin (Chronicle Books, 1997)