Double Infusion Calculations

Hello all,

I was wondering if someone could help me out with some calculations. I am programming an application to use on my home brews and it works well for my single infusion... however, my double infusion calculations are off. For example, the first target temp is 156 and the strike water temp would be 168.48 if the grain temp is 73 and the mash thickness is 1.33 qts/lb and the grain bill is 15.

1st strike temp = (((((grain bill * 0.05) + ((grain bill * mash thickness) / 4) * 1) * target temp) - ((grain bill * 0.05)* grain temperature)) / ((grain bill * mash thickness) / 4) * 1);

I am just a little confused on how to get it from 156 to my next temperature for the double infusion. For example, if my 2nd temp were to be 165.. I am unable to recieve the correct strike temp. I believe that the correct calculation would be 166.35 and I got this by entering in the varibles grain temp as 156 and the target temp as 165. Not to sure what to do. I think I am probably over thinking this.

If you need more information, let me know. Thank you!

I believe the variable changes for the second infusion. In this case you use boiling(212 deg) water and the variable is the volume required to raise the mash temp up to your desired temp.

73Drvr said:

I believe the variable changes for the second infusion. In this case you use boiling(212 deg) water and the variable is the volume required to raise the mash temp up to your desired temp.

Click to expand...

I agree with this, and you also need to take account of the 20 qt of 156F water that was added at dough in. Your formula does not take this into account. Also, to get accurate results, you need to take the thermal mass of the mash tun into account. I suspect your constant of 0.05 does this to a certain extent, but that would not be accurate if you changed the grain bill.

-a.