Honeycomb Candy - Cooking with CO2

    Kids, honeycomb candy is easy to make and has an interesting texture that is caused by carbon dioxide bubbles trapped inside it. The carbon dioxide is produced when baking soda (sodium bicarbonate) is added to a hot simple syrup. The bubbles in the candy make it light and give it a honeycomb appearance.

    Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.


    • 3/4 cup sugar 
    • 2 tablespoons honey 
    • 2 tablespoons water 
    • 1-1/2 teaspoons baking soda 
    • a candy thermometer



    • Grease a cookie sheet using oil, butter, or non-stick cooking spray. 
    • Add the sugar, honey, and water to a saucepan. 
    • Have an adult partner cook the ingredients over high heat, without stirring, until the mixture reaches 300°F. The sugar will melt, small bubbles will form, the bubbles will become larger, and then the sugar will start to carmelize to an amber color. 
    • When the temperature reaches 300°F, ask your adult partner to remove the pan from heat and whisk the baking soda into the hot syrup. This will cause the syrup to foam up. 
    • Stir just enough to mix the ingredients, and then have your adult partner pour the mixture onto the greased baking sheet. Don’t spread out the candy, as this would cause your bubbles to pop. 
    • Allow the honeycomb candy to cool, then break or cut it into pieces. 
    • Store it in an airtight container. 


    The creation of carbon dioxide (CO2) gas in the candy is the same process that is used in making some baked goods. The honeycomb candy forms a hard shell around the bubbles.

    By Kathleen Carrado Gregar, PhD, Argonne National Labs
    [email protected]
    May 2014


    By Anne Marie Helmenstine, Ph.D.