The Exploratorium

...Chocolate       Activity

A Question of Temperature

Tempering is a method of melting and cooling chocolate. It gives chocolate a shiny luster and that great "snap" you hear when you break the candy into bite-sized pieces.

Tempering chocolate not only produces some delicious results, it's also an opportunity to learn a little science. Temperature plays an important role in the candy-making process. Different fat groups in chocolate have different melting points. The tempering process stabilizes the cocoa butter (fat) crystals found in chocolate so that they become more uniform in size.

There a several ways to temper chocolate at home. We've selected one of the easier methods. Angela Arzave, Pastry Chef of EOS restaurant in San Francisco, showed us a simple method and some great ways of making chocolate candies and treats.

  sauce pan and bowl
  candy forks

Essential Ingredients & Tools

  • Couverture -- (12 oz or more) A special type of chocolate used in patisserie and confectionery (it means "to cover" or "to coat"). Couverture, which you may be able to find in a gourmet food store, flows more readily than chocolate found in candy bars. If unavailable, use a good-quality semisweet or bittersweet chocolate with a high cocoa butter content.
  • Saucepan
  • Metal bowl -- The metal bowl needs to fit on top of the saucepan
  • Cooking thermometer -- Angela recommends an "insta-read" or a chocolate thermometer.
  • Rubber spatula
  • Fork or candy forks -- Candy forks, available at gourmet cooking shops, work best, but a regular fork will do
  • A cookie sheet lined with parchment paper or foil (if you use foil, make sure to keep it smooth). The pros use a marble slab; if you have one, use it.


Optional Ingredients & Tools

  • Fruit -- Strawberries and bananas work great, but you can also use slices of apples or pears.
  • Balloons -- Small balloons can be used to create "chocolate cups"; you'll also need a hat pin to let the air of the balloon.

To Do and Notice
Before you begin, see the sidebars on the next page to decide what type of candy you'd like to make. You'll have to prepare the ingredients before you start tempering the chocolate.

Important Note:
Make sure your ingredients, tools, and work environment are completely dry during the entire process! Even a small amount of water will turn your smooth liquid chocolate into a sticky, lumpy mess. Also be sure that your kitchen is not too hot. The room's temperature should be 70 degrees or lower. Now you're ready to begin.




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