Originally Posted by surf71
In general how much are you adding to bring it up to 165?
I doubt you want to use my general usage for yourself, but I use about 6 qt near boiling water for a 10 lb grain bill mashed at 1 qt per lb at 150F.
You probably mash hotter, in which case you wouldn't need as much water. You probably mash thinner, in which case you will need more water, and the thermal mass of my MLT is probably different than yours in which case you would need more or less water.
I use Promash to perform the strike and mash-out calculations, but because I pre-heat the tun when doughing in, I specify the thermal mass of the tun as 0. This works well for the strike water temperature. (I heat the strike water about 10 degrees hotter than the calculator says, pour in in the MLT, wait for the temperature to drop to the calculated temperature, and stir in the grains. I always hit the correct mash temperature without any problem.
For the mash out, I tell Promash I want to raise the temperature to 168, and dial down the infusion water temperature to about 205F. Then I round off the qt required to something that I can measure easily. This always gives me something pretty close to 165.
One of these days, I may write a program to calculate everything accurately, but that's pretty low on my list of priorities.