Gum paste, fondant and modeling chocolate are the primary mediums though which cake decorators express their art. But what are they and when is it appropriate to use one over the other? Below you will find a general guideline.
Gum paste is pliable dough that made primarily from egg whites, powdered sugar and a hardening agent like tylose powder. Gum paste dries quickly and becomes hard and does not have a sweet taste like fondant or modeling chocolate.
Gum paste is great for making flowers and other figures that need stability or to maintain their shape. Since gum paste is so durable it can also be rolled thinner than fondant without tearing. Since it dries so quickly, it is important to keep any portion of gum paste that is not currently being used wrapped tightly in plastic wrap to prevent drying. Using shortening on your work surface or on your hands may also be helpful allow more working time with gum paste and to prevent cracking.
Gum paste can come premade, you can buy a mix or you can make your own.
Since gum paste is not as sweet or palatable as fondant or modeling chocolate many decorators use a 50/50 mix of gum paste to fondant or add tylose to fondant to stabilize it enough for modeling (click here for a homemade gum paste from fondant recipe).
Fondant is also pliable dough made from sugar, water, gelatin, and glycerol. Fondant does not dry as fast as gum paste and does not become as hard or stiff. Fondant has a sweeter taste and is more palatable then gum paste.
Fondant is primarily used to cover cakes and give them a smooth appearance. Fondant can be used to make lettering or other designs that will lie flat on your cake and that do not need any sort of stability to maintain their structure. Using fondant to create a figure (without adding tylose to harden it) will result in your figure drooping down on itself or collapsing under its own weight (definitely not fun!).
Fondant can also be bought premade (and in many colors as well) or you can also make your own.
Modeling chocolate is a chocolate paste made by melting chocolate and combining it with corn syrup, that when kneaded, it becomes pliable (the texture is similar to that of a tootsie roll). It will dry harder than fondant but not as hard as gum paste, and it also has great flavor (hey, it’s chocolate!).
Modeling chocolate can be used to decorate and cover cakes or it can be used as a sculpting material to create figures. It is especially great when creating figures that have a lot of intricate detail which is not easy to achieve using fondant or gum paste.
Modeling chocolate can be bought premade or you can make your own.