Now, after you have beaten the ingredients for the flan together, you might very well end up with foam on top. This wont hurt anything, however, as you might imagine, the foam offers up more surface area, and so if you have foam on the top of your flan, you tend to end up with a burn layer/crust on the bottum of your flan (you flip the container over to serve). If you want to skip the next step, feel free! But, I don't like to have that crust in my flan, so...
  
 
 Step 13:

I dont know what this thing is, but it will work. It will act as a strainer, and all (or close to all) of the bubbles/foam will get stuck in the strainer. This makes a big difference in my opinion, but really might not be worth the effort, it is up to you.