My sister is a chemical engineer and I got her to help me out with a spreadsheet to calculate what the optimal water temp BEFORE adding a quantity of grain is. Edit how many pounds of grain, temp of the grain (whatever your room temp) how many QUARTS of water, and desired mashing temp and then use the "SOLVER" tool in excel to calculate the exact temp the water should be when you add your grain.
Be careful when editing cells because some of them are dependent on others and you will break the spreadsheet, I wouldn't edit anything except the blocked off cells unless you are pretty comfortable with excel.
Hope this helps some people
Mash Temp Solver.xls
Just a quick comment, you should be able to write a simple formula that will give you the mash temperature without using "solver" tool
This is a good start.
Best I can tell, this would only be of use when mashing straight malt. Right?