When you think about it, chocolate is a miracle. Not just in the magical way it ends arguments, soothes woes and wins love (as well as puts on pounds), but chemically.
That hard, shiny shell on a piece of chocolate candy doesn't come easily. It is the result of some pretty tricky manipulation. As in some New Age phenomenon, the crystals all need to be lined up.
If you don't believe it, try melting some chocolate and dipping something into it. More than likely, you'll end up with something pretty darned ugly.
That's because the chocolate is out of temper.
Tempering chocolate is something best left to pastry chefs, candy makers and the truly obsessed.
The problem is that a bar of hard chocolate gets its crisp structure and glossy shine from having the cocoa fat crystals aligned in a particular formation. When the crystals melt, the formation is lost. The chocolate forms crystals and solidifies again when it cools. But it's unlikely that it will go back to that perfect arrangement.
There are four primary crystalline arrangements for fat, and only one (called beta-prime, if you really care) is the correct crystal for tempered chocolate.
In fact, it is true of almost all fats. That's one reason melted butter that solidifies never looks as smooth and waxy as it did when it came out of the package. (The other reason is that the water and milk solids have fallen out of emulsion, but that's another story.) Carefully developed beta-prime crystals are also the secret behind shortening's glossy, smooth appearance.
Fortunately, chocolate makers have learned how to realign the melted crystals. The process is called tempering. Traditionally, it's done by what is called the tablier method: Chocolate is melted to 88 degrees to 90 degrees and then two-thirds of it is poured out on a cold table. It is worked back and forth with a spatula until it reaches a temperature of about 81 degrees (this encourages the creation of those darned beta-prime crystals).
At this point, the cooled part is added back to the rest of the melted chocolate and the whole is mixed until all the chocolate cools in lock step with the beta-prime crystals.
Obviously, this is a process that poses problems for the home cook, who not only doesn't have a cold table but also probably doesn't have a thermometer that will measure accurately in those temperature ranges. Even home medical thermometers go down only to 94 degrees.
Really dedicated chocolatiers use a special chocolate thermometer that is accurate at that temperature range (the truly obsessed can buy a home tempering machine like the Sinsation Chocolate Maker, which replicates the tablier process mechanically. It's $299, plus shipping and tax at http://www.iic.com).
From time to time, people have offered alternatives. Jacques Torres, pastry chef at Le Cirque in New York and author of the recently published "Dessert Circus at Home" (William Morrow, $28), suggests melting the chocolate in a microwave for 30 seconds on high, then whipping it with an immersion blender. He also says you can "seed" chocolate with beta-prime crystals by adding small pieces of unmelted chocolate to melted chocolate (about 1/4 of the total weight) and beating it with an immersion blender.
Sounds simple. Unfortunately, we could get neither method to work in the Times test kitchen.
In her food-science column in this month's Fine Cooking magazine, Shirley Corriher points out that the beta-prime crystals melt at a slightly higher temperature than the other fats in chocolate. She suggests that if you merely melt two-thirds of the chocolate to between 89 degrees and 91 degrees, you can stir the rest back in. As long as the whole doesn't exceed 92 degrees, your chocolate should be fine. She suggests using a laboratory thermometer. Most home cooks don't have one of those, either.
The best advice? Forget tempering. In the first place, it is necessary only for pure chocolate that will be used as a coating or decoration. It's not necessary for chocolate that is cooked with other ingredients.
It's also easy to disguise untempered chocolate, to hide its physical imperfections. This is the approach San Francisco Bay Area chocolate queen Alice Medrich takes (quite emphatically, in fact) in her book "Cocolat" (Warner Books, 1990, $35).
"The No. 1 mystique that surrounds chocolate has to do with tempering," she writes. "Everyone wants to temper! Many do not quite understand what tempering is, or why they want to do it, but do it they must. From the dessert-maker's point of view, I take a radical position: I do not think it is necessary or practical to temper."
If your heart is set on serving truffles for dinner, go ahead and dip them in melted chocolate, but then just dust them with cocoa powder.
It may lack the magic of perfectly arranged beta-prime crystals, but at least you'll have your sanity.