Gelatin or Gelatine is a protein extracted from animal bones, and is used as a thickening and gelling agent. It is popular for it’s clear set and for the fact that it doesn’t need to be boiled to thicken, in the ways that flour and cornstarch do. It comes, mostly, in 2 forms – powder and sheet/leaf.
Some handy facts about gelatin:
- 1 sheet weighs between 2-3 grams depending on which brand you buy. I’ve really only seen one brand commercially in Vancouver and that’s Kessko from Germany. Different brands of gelatin do have different gelling powers, so check with the manufacturer on the recommended amount to use.
- Leaf gelatin and powdered gelatin have the same thickening power gram for gram.
- You can substitute 1.2tsp of powdered gelatin per sheet.
- There are about 12 level teaspoons of gelatin per ounce, and about 10 sheets in an ounce.
- To substitute grams of powdered per sheet, use about 2.5g (about 0.09oz)
All gelatin has to be bloomed and melted before it can be used. To bloom leaf gelatin, soak it in a cold water. The colder the water the better as gelatin melts at a very low temperature and the sheets will break up if the water is not really cold. Let it sit until the leaves are soft and pliable, about 5 minutes. Drain well before using. To bloom powdered gelatin, mix with an equal quantity of again very cold water and let sit until it thickens into a grainy gum. Depending on what you will be using it for the gelatin can now be added to your recipe.
It should be added to something warm or hot to ensure it disolves fully. I heard a story once at school, about a mousse cake being returned because it had ‘plastic bags’ in it. It was in fact unmelted gelatin sheets. For something like a jelly, you can warm some of your liquid, add the gelatin to that, and then add that mix back into the rest of the liquid. Keep in mind though that once gelatin is cold or even cool, you will notice it thickening.
If your master mix is too cold when you add your warm melted gelatin, it might seize and form chunks. If you’re making a jelly, or anything without incorperated air (whipped cream, or meringue…), you can warm the mix up slightly and that should homogenize it. It gets trickier if you have something whipped though as the air will be knocked out at warm temperatures. This is why a smooth mousse can be tricky. Even the pros screw it up sometimes. The best way around it is to try and keep all your liquids warm, and let them cool together once the gelatin has been added, then once that mix is just about room temperature, fold on your whipped cream or whites. Work fast or the mix will set lumpy.
