Thank guys for your help. I had thought about the weighted average of the gravities but for me its kind of hard to measure exactly how much I have inside the fermentor since it has a not even shape and its not transparent.
Now I'm gonna use the brewing calculator tip that some of you gave...
I'm convinced now that it is better for yeast if I add sugar when krausen is slowing down. If I understood well, too much substrate in the wort can inhibit the cell's growth and the yeast will go directly to the glucose and it can leave some other fermentable sugars behind. So it would take...
