Gelatin (a stabilizer derived from animal collagen) can make gelatin desserts out of just about any liquid, including your favorite juice-based cocktails. Gelatin can also give a gorgeous sheen to icings and, when adds body to mousses, Bavarian cream, and sweet, cold souffles. It comes in powdered and sheet (or leaf) form. In Europe, sheet gelatin is more widely used,and many pastry chefs prefer it, but powdered gelatin is more readily available.
A 1/4-oz. packet of gelatin powder contains about 2-3/4 tsp.; 1 tsp. Knox brand powdered = 2 sheets
Agar-agar, derived from seaweed, can be a good alternative, especially for vegetarians. It does set up firmer, so you may need to experiment and adjustment your recipe accordingly.
Powdered gelatin is available at the supermarket, usually in the baking section. Look for sheet gelatin at specialty baking shops or online.
Use 1 generous teaspoon gelatin powder per cup of liquid, more or less. The amount you use depends on how gelled you like your gelatin. You may have to experiment a bit at first?just keep in mind that too much gelatin creates a bouncy texture. Thoroughly dissolve the gelatin by sprinkling it over a cool liquid and letting it ?bloom,? or soften, for several minutes before heating to dissolve the gelatin. Be sure the gelatin dissolves completely or the finished texture won?t be smooth. Soften sheet gelatin by soaking it in cold water for about 10 min. Squeeze it to drain excess liquid before you melt it into the liquid ingredients in the recipe.
Dried gelatin keeps indefinitely if kept in a cool dry place.