1. Hydrate the Gelatin: Unlike most other ingredients we work with, gelatin can't be added directly into the recipe. It needs to be mixed with a little bit of water before being added in order to hydrate (or "bloom") the grains of gelatin. It will take on an applesauce-like consistency and eventually set into a solid if not used right away.
If this happens, it's best to soften it back into a liquid before adding it to the rest of the recipe. This is easily and quickly done by setting the bowl with the gelatin in a small saucepan filled with an inch of water over medium-high heat.
2. Add Gelatin to a Warm Base: In other words, add the gelatin while whatever you're adding it to is still warm. If the base is cool, you can develop roping in your final recipe, which are strings of gelatin made when the gelatin cooled too quickly.
3. Use the Base Right Away: Gelatin starts to work pretty quickly once it's added into the recipe, so be sure the mold you're using is ready and waiting. If it does start to set up and you're not quite ready, you can re-heat the base to soften the gelatin again. This won't damage the gelatin or its ability to make your recipe solidify. Also, it's best to add the gelatin as one of the very last steps in cooking.
4. Time, Temperature, and Concentration: These three things affect how quickly and strongly the gelatin works. The longer your finished recipe sits, the more rubbery and solidified it gets. This is why Jello always tasted better on the first day than the fifth day. Cool temperatures also make the gelatin stronger. If you're running late and you don't have time to let your Orange Smilies sit, stick them in the freezer for a few minutes. And obviously, how much gelatin you use per cup of liquid affects how solid it becomes (more gelatin makes it more solid).
5. A Few Random Final Facts:
• One tablespoon of gelatin will set two cups of liquid
• One package of powdered gelatin is roughly equal to one tablespoon.
• Four sheets of gelatin equals one tablespoon of powdered gelatin.
• If a recipe says to "bloom" the gelatin, that means to hydrate it in a small amount of water.
How often do you find yourself working with gelatin?
Related: Tip: Stabilize Whipped Cream