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-   -   Accounting for Temp Lost During Mash In? (http://www.homebrewtalk.com/f36/accounting-temp-lost-during-mash-367788/)

timmah84 11-14-2012 08:11 PM

Accounting for Temp Lost During Mash In?
 
So I have about 6 all grain brews under my belt.

I preheat my mash tun (rubbermaid 10g cooler) with the strike water. I usually heat that strike water to 185 and let it get down to the target temp (around 163-166, depending on the mash temp I want (152-155). I let it sit for about 15 minutes at 185 to absorb the temperature to reduce heat loss. If needed, I will stir the water to bring down the temp or simply let it sit with the lid off.

Once I hit the correct temp, I dough in and stir like hell, and take a few different temp readings.

This is where the problem starts...usually my degrees are a bit off, like 1 or 2 degrees, which I assume is from stirring the crap out of the mash. Should I be compensating the temperature from 163-165 to like 166-168 to avoid the mash temp loss from stirring? Ami I not stirring it enough, where I am taking reading on cold areas? Am I worrying too much?

My brewhouse efficiencies are around 75-85%.

Any advice would be great!

bioguy 11-14-2012 08:17 PM

It seems to me that if your procedure is making you miss 1 or 2 degrees low, then keep your procedure the same except increase your strike temp by 1 or 2 degrees. Your idea of compensating the temp is what I'd go with.

45_70sharps 11-14-2012 08:20 PM

Quote:

Originally Posted by bioguy (Post 4589778)
It seems to me that if your procedure is making you miss 1 or 2 degrees low, then keep your procedure the same except increase your strike temp by 1 or 2 degrees.

That's what I would do.
If you have a procedure and it's consistent, then just adjust for the 2 loss and you're done.

tally350z 11-14-2012 08:22 PM

As long as when you mash in and have the correct temp and you have no dough balls than I would stop stirring. Take your temp readings in multiple places in your Mt and close the lid and let it sit. What type of cooler are you using? With my HD cooler I only loose 1-2 degrees over a 60 minute mash..

timmah84 11-14-2012 08:44 PM

Quote:

Originally Posted by tally350z (Post 4589792)
As long as when you mash in and have the correct temp and you have no dough balls than I would stop stirring. Take your temp readings in multiple places in your Mt and close the lid and let it sit. What type of cooler are you using? With my HD cooler I only loose 1-2 degrees over a 60 minute mash..

I am using the HD 10 gal cooler as well. I'll have to up my strike temp.

BBL_Brewer 11-14-2012 09:03 PM

You have a couple options. The easy route is to do what was already suggested and just bump up your strike temp a little. But, if you're not scared of a little math, you can do the following.

Follow the link and determine what your heat loss is and convert it to an equivalent volume of water. The website will explain this in more detail. http://www.haandbryg.dk/mashcalc.html

At this point, you can use the infusion equation instead of the strike equation to determine your strike temp. To do this, solve for Aw (the actual temperature of the infusion water).

Example

Say you go the website and determine your heat loss to be equivalent to 0.46 quarts of water. Lets say your grain temp is 70F and you have 12 lbs of it. You want to mash in with 12 quarts of water and hit 154F. The math goes as follows.

Aw = [(T2-T1)(.2G + Wm) / Vi] + T2 Where T1 = Grain temp F, T2 = Target mash temp F, G = Total amount of grain in pounds, Wm = The equivalent volume of water that you determine, and Vi = Infusion volume (or in this case strike water volume)

Aw = [(154-70)(.2*12 + 0.46) / 12] +154

Aw = 174 So, your stike temp is 174F with heat loss accounted for.

duboman 11-14-2012 09:04 PM

This might help:
Prior to brewing allow the grain and MT to come to room temperature inside. My typical grain bills are 12-16lbs and I use a Rubbermaid 10 gallon Bev cooler. I heat my strike water to about 168 degrees and add to cooler, then dough in and stir as I go. By the time the grain is in and mixed I have arrived at my desired mash temp which is usually 152F, close the lid and let it sit. I only lose 1-2 degrees over 60 minutes as well.

Perhaps you are striking at too high a temp and working too hard to bring the temp down:) My mash/lauter efficiency is a consistent 82% and I mill my own grain.

tally350z 11-14-2012 10:15 PM

When I first started doing all grain I was too worried about losing more temperature in the MT than I wanted, which is why I would over hit my strike temp and add the grains too hot and then stir and stir to cool. Sometimes adding cold water, but then after a few batches I learned I was over thinking it I have been hitting my numbers spot on..


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