The adjust Mash page allows you to give the conditions of your mash and calculate how much water to add at a given temperature in order to achieve a target temperature. This is most useful for me when you have a mash in progress and need to correct for a missed temperature. So for instance you’ve doughed in 12 quarts of water in to 10 pounds of grain and your mash temperature works out to be 145 but you wanted to target 155 degrees. Here are the values you’d punch in to the “Adjust Mash” Page in US units:
Water Volume 12 qts
Grain Weight 10 lbs
Current Mash Temp 145 F
Target Mash Temp 155 F
At this point you still have 1 empty input box which is the “Water Addition Temp”. There are a couple of ways to use this because it effects the two yellow(calculated) boxes which are “Water to Add” and “Final Water to Grain” ratio. For me I don’t want to go over a “Final Water to Grain” ration of 1.50 so I adjust “Water Addition Temp” until I have a number under this. If you want to guess you can guess high starting at boiling or punch in the temperature of the sparge water you have already setup. In any event for the case of this example we’ll say you set “Water Addition Temp” to 200 degrees. You then know you have to add 2.51 qts at this temperature to hit 155 F.