So last Sunday I brewed my first AG biab and I was using beer smith to determine when I should dough in. It told me 161 degrees should make my mash water 154 degrees when my grain was 68 degrees. My kettle measurments are 15 x 15 inches and holds 13.25 gallons. Was using 8 gallons at the time. Long story short when I doughed in my water temp only dropped to 159 and held there for like 30 mins before finally dropping lower. What calculations should I use in the future so this is more on the money ? Or is it one of them things that bc it was my first time using the equipment, that I have to get it dialed in and start predicting what the temp out come will really be ? Also might I need to look at different settings on beer smith as I'm also new to that. Or might there be a better sight to help calculate this for biab style ? Thanks