# Mash Calculator Issue?

Discussion in 'General Brewing Discussions' started by ChicoBrewer, Feb 3, 2019.

1. ### ChicoBrewer Well-Known Member

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#1
My brew session went quite well yesterday using BF. I use it for every brew day and now that the brew steps are working I really like it. (I keep a moleskine notebook as well)

I recently changed my mash/batch sparge process based on an article @Yooper pointed me to in another thread. It goes like this.

• Add boiling to mashout at 168 for ten minutes
• drain to kettle
• add remaining water at 168 to batch sparge.
• drain to kettle
This has raised my kettle efficiency by 10 points.

The issue I have had with the two brew days I have used this process for is that the add boiling step only raises my mash temp to 164. I am using the mash calculator to determine how much boiling water to add and on both occasions I have come up low. I then pull some wort out and heat it on the stove to try to raise the temp to 168.

Has anyone else experienced issues with the mash calculator? I get perfect temps with the first step (Strike) but add boiling comes up short. I almost went down a rabbit hole and started looking for thermodynamic equations for specific heat but then common sense overtook me. . .

2. ### philjohnwilliams Well-Known Member

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#2
I think that the calculator is right in a perfect system, but it can't account for all means of heat loss. What I think (and let me stress this is a wild ass guess) is that you are losing more heat between taking your mash out water off the heat and adding it to the mash than the calculator is accounting for. Heat loss will occur faster when the difference between hot and cold ( in this case your water and the ambient air) is greater so you would likely see more heat loss with your mash out water than your strike water, which is why you may hit your mash in temps but not your mash out. You could correct this by adding a couple of quarts extra mash out water, the exact amount you would probably have to determine by trail and error.