A sugar-based dough, fondant should be soft and pliable. When smoothed over a cake, fondant gives a sleek, silky finish. Molded into different shapes, fondant adds decorative detail to confectionery treats. The versatility of the fondant dough also makes it a sweet choice for filling in candies such as cherry cordials and mint patties. Left to harden, fondant becomes difficult to handle, requiring a softening process to restore moisture.
Kneading -- squeezing, stretching, folding and pressing -- breathes new life into hardened fondant when you add a little slip to the process. Add about 1 teaspoon of glycerin for every 1 pound of fondant. As you knead, the glycerin makes hardened fondant more pliable by trapping water molecules and rehydrating the icing. Vegetable shortening is just as effective. Coat your fingers with the shortening before kneading the hardened fondant.
A short stint in the microwave turns a hard fondant into a more pliable product. Place the fondant in a microwavable bowl and heat in five-second intervals. To avoid getting burned by hot fondant, wait until it is cool to the touch and then knead the fondant after each burst of microwaving. If the fondant still lacks flexibility, pop it back in the microwave and repeat.
Try not to overdo it when adding glycerin or vegetable shortening to fondant. A little goes a long way, especially when it comes to shortening. Fondant should be smooth, light and easy to work with. If you find that the fondant is becoming heavy, gooey or stretchy, you may have added too much. Sprinkle a light dusting of cornstarch over the fondant and knead until you are happy with the consistency
Long-term exposure to air causes fondant to become hard and dry. Keep your fondant soft and workable by storing it in an airtight container or tightly wrapped in a piece of plastic wrap. Because too much moisture destroys the integrity of the fondant, refrigeration and freezing is not recommended because the opening and closing of the door makes it difficult to control humidity levels inside. Kept in an airtight container, fondant remains safe to use for several months.