If you've ever wondered what makes the chocolate in bonbons so smooth and shiny, it's a technique called tempering, which is a method of melting chocolate to a specific temperature in order for the fat and sugar molecules to collide so that when the chocolate sets, it creates an attractive sheen and toothsome snap. While it may seem like an elusive, mysterious technique that is better left to chocolatiers, it can be done at home in about two hours, as long as you have a candy thermometer and the proper chocolate. For the adventurous pastry cooks out there, here's how to temper dark chocolate, in pictures.
Use Couverture Chocolate
What makes chocolate candies so silky smooth (and expensive) is the high percentage of cocoa butter. The fat content in cocoa butter not only improves the flavor and texture of the chocolate, but also makes melting the chocolate and enrobing (or covering) items an easier process. That said, for the best and easiest experience with tempering chocolate, use couverture wafers. Guittard or TCHO are my go-tos, but experiment with different companies to find one that you love. Today, I'm using TCHO 68 percent  ($76 for a 6.6-pound bag).
Weigh Out Chocolate
Weigh two pounds of chocolate on a scale. Some bonbon and truffle recipes written for the home kitchen will call for one pound of chocolate, but my experience has been that one pound of chocolate is not enough to hold a temper. I recommend always using two pounds of chocolate, unless the recipe specifies more.
Here's why: tempering chocolate requires precise temperatures. When you only use a small amount of chocolate, it will cool and thus harden quicker than you are able to make use of it. You want the chocolate to hold its temper for as long as possible, and using more chocolate enables you to spend more time dipping and enrobing your confections and less time worrying about bringing the chocolate back up to the proper temperature.
It should be noted that any leftover tempered chocolate can be reused and retempered at another time. You can keep the tempered chocolate in the bowl and wrap it in plastic wrap. Alternatively, you can transfer it to a baking sheet with a silicone nonstick pad and allow the chocolate to harden before breaking it into pieces and storing it in a resealable plastic bag.
Divide the chocolate into two piles. Place 75 percent of the chocolate in a sturdy stainless steel bowl. It will be used for the melting chocolate. Reserve 25 percent of the chocolate, called the seeding chocolate, in a small bowl. It will be added to the melted chocolate later.
Melt With Indirect Heat
The easiest way to temper is by using a tempering machine , but most home cooks don't have one of those lying around! Chocolate needs to be melted with an indirect heat source. I prefer to use a double-boiler method, because it allows you to develop a keener eye and feel for the difference in appearance and heaviness of chocolate that is 90°F versus 120°F.
Bring a small pot of water to a boil. Turn the flame off, and place the bowl of chocolate over the pot. Allow the chocolate to melt by the steam rising to the bottom of the bowl. Use a candy thermometer to monitor the temperature; however, be sure to stick it in the chocolate without touching the bowl, which can give a false reading. Once the temperature reaches between 115°F to 120°F, quickly remove it from the stove.
Warning! Do not allow even a drop of water to touch the chocolate. Water is chocolate's worst enemy. Even one drop will turn the entire bowl into an unworkable mess. If this happens, use the chocolate for brownies or hot chocolate, but forget about tempering.
Seeding the Chocolate
Stir the chocolate a few times. At its highest temperature, the chocolate should feel thin and easy to stir.
The next step is seeding the chocolate, or adding pieces of the unmelted chocolate to lower the overall temperature of the melted chocolate. Take the seeding chocolate (the 25 percent that you reserved earlier) and add a few pieces. Stir slowly, so you do not incorporate air bubbles. Once the chocolate has melted, continue to add a few pieces at a time.
You may or may not need to incorporate all the chocolate, because factors like how much total chocolate you are using and how cold your kitchen is will affect how quickly the chocolate cools. If you find that the chocolate you are adding is not melting, stop adding the pieces and let the chocolate sit, stirring it occasionally to cool until it reaches 86°F. If there are any unmelted pieces of chocolate, remove them from the bowl before going on to the next step.
When the chocolate has reached 86°F, use a hair blow-dryer to heat the sides of the bowl in five- to 10-second increments until the temperature reads between 88°F and 90°F. This is the proper range for tempered chocolate.
Test the Temper
Check the temper by dipping a spoon in the chocolate and letting it sit out for around five minutes. It should dry and look shiny and hard, as pictured on the left. If it passes the tempering test, then start dipping your caramels, cookies, or fruit. Keep monitoring the temperature, and if the chocolate cools, use the hair dryer to zap the chocolate for a few seconds to bring it back to the right temperature.
If it looks oily on top, has streaks, or develops a bloom (the fats rise to the surface, giving the chocolate a chalky, white appearance, as pictured on the right), then the chocolate is not tempered, and you will need to start over!
Use the Chocolate in These Recipes
Now that your chocolate is tempered, use it to enrobe (a fancy word for "dipping") a variety of confections as well as making other candies:
- Saltine cracker toffee 
- Chocolate bark 
- Pretzel, caramel, and chocolate clusters 
- Caramel candy 
- Vanilla marshmallows 
If you have any leftover chocolate after you've done your dipping, simply pour it out on a baking pan with a silpat  or parchment paper and allow it to dry. After it hardens, you can chop it up and temper it again next time.