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HopRodGR · 07-03-2012, 07:12 PM

Hi All,

I'm looking for the equation that calculates the temperature you should heat your batch sparge water to, based on the temperature of the soaked grain remaining after the first runnings are drained.

I'm currently attempting to put together an Excel spreadsheet that will give me a table of temperatures, since predicting what temperature the grain will be after draining the mash is difficult to predict. Having a range of values allows me to easily reference the right sparge water temperature to heat to.

My initial thought is calculating the weight of the grain, which would be the dry weight plus the weight of the water absorbed, against the weight of the sparge water, factoring in temperatures, would get me there. However, this doesn't take into account the density differences in a pile of wet grain vs. just water.

Here is my simple calc:

(Weight of wet grain/(Weight of grain + sparge water))*Grain Temp + (Weight of Sparge Water/(Weight of grain + sparge water))*Sparge Water Temp = Temperature of Batch Sparge.

Since the weight of water is 8.35lb/gal and the generally accepted absorption of grain is 0.13gal/lb, it should be easy enough to plug these values in.

Have I over-simplified and missed an important variable or this or does this look right?

ChandlerBang · 07-03-2012, 08:59 PM

The grain temp at mash out should be whatever your mash temp was. There are loads of calculators on the interwebs to do this. Hang on, I'll go find one.

ChandlerBang · 07-03-2012, 09:01 PM

http://www.brew365.com/mash_sparge_water_calculator.php

Here's one. I use one on my phone (android).

**tre9er** · 07-03-2012, 09:02 PM

My formula looks like this, FWIW:

=(MashT1+0.192*(MashT1-GrainT)/StrikePerLb)

HopRodGR · 07-04-2012, 01:10 AM

Thanks for the replies. I've found that when I drain my runnings, the remaining mash is almost never the same temp as the one I actually mashed at. Usually, it's lower, and when I heat my sparge water to the temp an online calculator calls for, I end up with a sparge temp that is too low, often in the low 160's. How to Brew has a mash in formula, but not one to account for grain that has absorbed water. With there being so many calculators online, I was looking to build my own model to give me a wide range if what I initially plug in for ending mash temp turns out to be wrong.

**tre9er** · 07-04-2012, 01:21 AM

It truly doesn't make a big difference

**oakbarn** · 08-20-2012, 11:37 PM

Did you ever make your xls. I have not found a good formula for the mash in temp with a set volume

**tre9er** · 08-20-2012, 11:40 PM

Quote:

Originally Posted by oakbarn

Did you ever make your xls. I have not found a good formula for the mash in temp with a set volume

I have an xls that I use for the entire recipe/process. I can share on drive if you wish

Denny · 08-21-2012, 07:47 PM

Quote:

Originally Posted by tre9er

It truly doesn't make a big difference

This is the TRUTH! I heat my batch sparge water to 190F for every brew. Kai has shown that you can even slarge with room temp water with no effect on beer quality or efficiency. It just doesn't matter.

HopRodGR · 08-22-2012, 01:22 PM

Quote:

Originally Posted by Denny

This is the TRUTH! I heat my batch sparge water to 190F for every brew. Kai has shown that you can even slarge with room temp water with no effect on beer quality or efficiency. It just doesn't matter.

That's really interesting, since as a newer homebrewer it is drilled into your head to get your sparge water as close as you can to 170 without going over, when it appears, that is really unnecessary. I generally like reading Kai's stuff so I'll have to dig up his write up on this too.