Calculating strike temp

TurboBrew · 03-27-2009, 05:01 PM

What the general consensus on the specific heat of grain. I have all the other variables, just need c of grain.

Beerrific · 03-27-2009, 05:29 PM

Here is the equation that Palmer suggests in How to Brew:

Quote:

Initial Infusion Equation:
Strike Water Temperature Tw = (.2/r)(T2 - T1) + T2

where:
r = The ratio of water to grain in quarts per pound.
T1 = The initial temperature (¡F) of the mash.
T2 = The target temperature (¡F) of the mash.
Tw = The actual temperature (¡F) of the infusion water.

So I think you can use that on its own or use it calculate the specific heat of grain in the exact form you want.

TurboBrew · 03-27-2009, 05:46 PM

What do you mean by the initial temp of the mash? The final temp should be 155 but how do I calculate the initial?

Beerrific · 03-27-2009, 05:52 PM

That is the temp of the grain.

Example:
Grain temp: 65
r=1.25
Mash target: 155

(.2/1.25)(155-65)+155=169.4

So you would use around 169F water.

**bull8042** · 03-27-2009, 07:58 PM

This is another great argument to get BeerSmith or another brewing software. If I had to remember the formulas, I would never be able to brew.

**FSR402** · 04-03-2009, 12:32 AM

Now how would you also deal with the temp of the tun?

<I use BS but I still like to know>

Beerrific · 04-03-2009, 01:14 AM

Quote:

Originally Posted by FSR402

Now how would you also deal with the temp of the tun?

I over heat mine by 5-7 degrees and let it come down to the temp that I know that water needs to be. Or you can pre-heat with a gallon of near boiling water.

**bull8042** · 04-03-2009, 01:14 AM

Quote:

Originally Posted by FSR402

Now how would you also deal with the temp of the tun?

<I use BS but I still like to know>

I have a HERMS system, so everything is at temp at the same time. But, what I did before when using a cooler..... if I needed to strike with 169F water, I would heat my water to 175F, dump it in the tun, leave the lid off and stir until it cooled to 169F. Then stir in the grains. I normally hit my temps dead on.
When I started mashing in a keg, I usually heated my water 10+ degrees over to adequately compensate for the heat absorbed and dissipated by the SS.

**FSR402** · 04-03-2009, 02:16 AM

Yeah I got all of that. I have my Beersmith all set so it gives me what I need to strike at and hit my temps (after I preheat the tun to 100*).
I was just wondering what the math would look like with the extra variable in there.

**jwic** · 06-17-2011, 07:43 PM

Quote:

Originally Posted by Beerrific

That is the temp of the grain.

Example:
Grain temp: 65
r=1.25
Mash target: 155

(.2/1.25)(155-65)+155=169.4

So you would use around 169F water.

So when it says "temperature of grains" it pretty much means room temperature, right? Why would they be any colder or hotter than room temp?