I have a few questions on using gelatin (sheets) in desserts. I'm not all good in making desserts, but I tempted to make this rhubarb mousse without a recipe, which turned out more or less as expected. I made a compote of just rhubarb and sugar, setting a small part aside to be used as a sauce. This means you can see in the picture how the consistency of the rhubarb compote was. To the hot rest I added gelatin sheets soaked in cold water. I used 4 sheets for around 500 grams of compote. Let the whole thing cool, then added whipped cream and folded that in. The sheets I used are a french brand called "Vahiné", sold in a package of 9 sheets weighing 17 grams in total or 1,8 gram per sheet. I also have "Dr. Oetker" sheets in a package of 12 sheets weighing 20 gram or 1,6 gram per sheet. My understanding is that normally the content of one whole package will be enough for 1 liter (around 1000 gram) of liquid to gelify. I used 500 gram fresh rhubarb in total. My questions are; 1. how do you determine the amount of gelatin needed in preparations like this mousse base or any other base? I aimed at the fact that most fruit is 90% water or so, and went from there without weighing exactly. I used a package of 500 gram fresh rhubarb. 2. If I wanted to make a bavarois (bavarian?), what would be a nice ratio rhubarb compote, whipped cream, beaten eggwhite? Also, do you sugar the eggwhite? 3. If I wanted to make a semifreddo aka parfait out of this, can I just use and freeze a bavarois mixture or do I need another ratio?