Temperatures vary with different chocolates. Call the manufacturer or check the package for proper temperature. Always use the best-quality couverture chocolate. Do not let water droplets get in the bowl, and to avoid an inaccurate reading, do not allow the thermometer to touch the bottom of the bowl. Using a serrated knife, chop chocolate into 1/4-inch pieces; place 12 ounces chopped chocolate in a dry metal bowl or the top of a double boiler. In a medium saucepan, bring 1 to 2 inches of water to a simmer; turn off heat. Set bowl of chocolate over pan. Stir gently with a rubber spatula until melted chocolate reaches 118 degrees on a chocolate thermometer. Remove bowl from pan; add remaining 4 ounces chocolate. Stir with rubber spatula until chocolate cools to between 82 degrees and 84 degrees; remove any unmelted pieces. Place bowl over pan; stir until thermometer reaches 88 degrees to 91 degrees. Use immediately.
Martha Stewart Weddings, Fall 2001