Calling all Engineers and the like

[sdixon]

So I am trying to calculate the water temp additions for a step mash for 5 BBL. I essentially want 3 steps, 122F, 152F and 168F. I have a single HLT so I have one temp in the HLT to deal with. Therfore I need to blend cold with HLT water to create my steps. Here are the calculations from Palmer:
http://www.homebrewtalk.com/wiki/index.php/Infusion_mashing

I'm trying to create a spreadsheet with the formula's embedded, but not sure why I can't seem to make it work? On this recipe, I'm using 130Kg of grain. Let's say grain temp of 70F. I need to come up with some combination of grain, water/temp additions to make this approach work.

Let's say an initial step of .75 ration or grain to water and then whatever temps and volumes make sense from there.

Just thought I would throw it out there in case we had some bored mathematicians ;-)

[chrismccull]

I can probably help with this on the weekend.

BeerSmith won't do this for you?

[Chris Craig]

No.  He's talking about adding a cold water and a hot water infusion to hit his targets.  Beersmith will calculate the temperature need for infusion, but not like this.

Wouldn't the absolute easiest way to accomplish this be HERMS using your HLT, or a RIMS tube?

[sdixon]

Actually, what I might be able to do is add a cold water line to the line coming from the HLT (Y junction with valve) and then a temp probe after the junction. Yhen I could manually adjust the cold water flow to get the infusion temp determined in BeerSmith. I would just need to ensure the HLT temp was at the max temp to add, in this case 205F.