What's the Difference Between Powdered and Sheet Gelatin?
If you follow The Great British Bake Off or have European cookbooks, you've probably come across references to sheet gelatin or gelatin leaves. Luckily for American bakers, sheet gelatin is increasingly available in the U.S., both in specialty stores and online. If you can't find it, here's a little primer on how to use both types, and how to substitute one for the other.
How to Use Powdered Gelatin
This needs to be rehydrated before you use it. Always use cold water (or juice, or other liquid)—if you start melting the gelatin before it's rehydrated, you'll have little dried granules sprinkled booger-like throughout your dessert. Sprinkle the gelatin over the liquid and set aside for 5 to 10 minutes to let it absorb; it'll swell up and look a bit like applesauce.
Once the gelatin is hydrated, it's time to melt it. You can do this by stirring it into a hot liquid like a custard (crème Anglaise) or juice, or you can melt it in a double boiler. If you're careful, you can even melt it in a stainless steel bowl set over a gas burner on your stove, but that's for gamblers and pros, because it's easy to scorch it or your fingers. Make sure the gelatin granules are fully dissolved before proceeding with your recipe.
How to Use Sheet Gelatin
To make things more complicated, there are different types of sheet gelatin, each with different gelling strengths or "bloom". I'm going with silver sheet gelatin, which I've used most often.
To use it you just put the gelatin sheets in a bowl filled with cold water. After they've been submerged about five minutes, they're re-hydrated. Hold them gently in one hand, and slick the water off the sheets with the fingers of your other hand. The gelatin dissolves quickly when stirred into a warm liquid or heated over a double boiler.
How to Work With Gelatin in Recipes
- There's a bit of "time's-a-wastin'" pressure when working with gelatin: once you fold a cold element like whipped cream into your room-temperature base, the gelatin will start to set. You need to have everything ready to go before you start mixing together the components of your dessert. Have your baked pie shell ready, or your cake layers, or your dessert glasses.
- If something comes up, you do have a save-this-for-later safety net: you can re-melt the gelatin. If it's in a custard or fruit juice base, just refrigerate it until you have time to complete your dessert. Gently heat the base until it's fluid, let it cool to room temperature, and proceed with the recipe. Once you fold in the whipped cream or meringue, though, it's time to pour the dessert into molds.
- Gelatin-stabilized desserts should chill 24 hours, or at least overnight, before serving.
How Much to Use
According to the authorities at Knox®, 1 envelope of powdered gelatin has the same gelling strength as 5 sheets (about 3 x 8.5 inches) leaf gelatin. According to other pastry chefs I admire, there's a range: David Lebovitz says "Three-and-a-half sheets seems to work best for me. I use sheets that are 3 inches by 5 inches." Are you making something you're going to slice? Add an extra half or whole sheet. Is it something you're spooning out of a dish? Keep it elegant and go for a texture on the softer side.
Favorite Gelatin-Stabilized Recipes
This is great piped on a pie—especially the Pumpkin Bavarian Cream Pie ("Tart"). As I noted on a photo for the recipe I posted, "I piped rosettes of whipped cream on the Pumpkin Bavarian Cream Tart and garnished with grated nutmeg. The cream held up well—about four days in the fridge (as long as the pie lasted!)."
It slices beautifully!
This is a great recipe for summer.
And here's one I intend to try for Christmas, using pasteurized egg whites for the filling: