# Mash Infusion and Rest Schedule Calculator

Discussion in 'General Brewing Discussions' started by Krimbos, Dec 15, 2014.

1. ### Krimbos Member

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#1
On the Mash Calculator page is the following note:

NOTE: The strike calculator assumes your tun will absorb heat (a few degrees will be absorbed by the mash tun, this varies widely by the type of mash tun). Even if you 'pre-heat' the tun with a little boiling water, this may still be the case. Do not stabilize the tun at the strike temperature, and then add grains, or you will overshoot.

I always figured that the strike temp is the water temp IN THE TUN at the time of grain addition

Is that wrong?

2. ### Ozarks Mountain Brew Moderator Staff Member

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#2
your strike temp is different for different systems, in most cases you adjust higher because the grain will cool the water down when adding in so it depends on the grain temp. I have a recirculating system so I only raise 4 degrees above my target temp, some 6 to 8 degrees.
also depends on how much grain your adding, if your doing a 15 gallon batch and your grain is at 70 and your strike water is at 152, the water temp will drop considerably, so you would heat your water 10 higher in that case

3. ### The Brew Mentor Well-Known Member

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#3
Krimbos
If your mash tun and strike water are at @ Strike temp, you have to think about the mass of the mash tun itself as adding temp to the mash.
There are actually 3 factors to consider, the grain, the water and the tun. The grain and water can be calculated out but if the tun itself is hotter (by pre-heating) then that heat will be transferred to the mash and you'll overshoot your strike temp.

Make sense?

Brian

How'd the OS come out? :mrgreen:

4. ### Krimbos Member

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#4
Thanks All

I understand the physics behind it all (heat absortion, etc)

Bottomline

Is the calc strike temp the stabilized temp in (preheated) mash before grain addition or temp reached in kettle before transfer?

I guess every system is different. I just find the comment confusing

5. ### Ozarks Mountain Brew Moderator Staff Member

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#5
sorry I misunderstood, strike temp is always before the grain is added no matter what calculator

6. ### Nosybear Well-Known Member

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#6
Strike temp is the temperature of the water when you pour it in the tun in our case. If you're using an externally heated system (RIMS, HERMS or even just heat under the tun), you can use the temperature of the liquor in the tun as the strike temp. For those of us using passive systems (Igloo coolers), the strike temp is the temperature of the water when you pour it in the tun. The passive system introduces one more variable, the heat required to bring the tun up to temp. Might be nice, Austin, if we could have a checkbox for active or passive systems in the calculator or maybe a mash tun heat loss adjustment (zero for actively heated systems, default 2°F for passive systems, adjustable based on user's empirical evidence).

7. ### Krimbos Member

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#7
I guess it ultimately comes down to how you calibrate your system

I prefer to stabilize the filled tun temp, then add. I will try to determine my loss as I move forward

I finally christened the keggle this weekend. Filling tun via ball valve is much preferable to handling large pots of hot water!!!

PS - BM - the owner of my LHBS says my OS is the best brew I have brought to him to date. He noticed the effect of the modified mashing!

8. ### The Brew Mentor Well-Known Member

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#8