Hello! i have been brewing serveral batches of porter. The OG is 1065 and theoretically the FG would be something around 1016. In my last batches, when i am ready to transfer from fermentor to a maturation tank i have a lot of yeast in suspension on my beer. When i am reading final gravity the beer do not have well atenuation even if i leave the it on the fermentor for several days. The FG is around 1025 to 1020. I use dry yeast (nottingham), i rehydrate it with water at 90°F. I use 3.5 to 4 packages of yeast to pitch a 1/2 BBL batch. I have checked the calcium levels on my water and adjusted it, i use to mash at 145 or 149°F maximum. I have a ranco temperature controller con my refrigerator in order to control fermentation. I dont know why i am having this yeast problem? please somebody help me!!