I have done two all grain kits one ,gal batches. the first time I ended up with much less than a gallon after boil.so this time I paid more attention to starting with enough wort to lose some during boil, and I boiled at a much lower temp...to the point that I was worried that it wasn't really boiling..just simmering. Still, ended up with even less than the first time. I added some water to get it up to the gal. mark but that should be a back up, not plan A. What am I doing wrong?