What do you use to calculate your strike temperature?

I found this on brewing techniques website and was curious if anyone used a similar formula or just use around 172°.

Aa+Bb=Cc

A=Specific Heat Grain, or lbs x .05
a=grain temp
B=Specific Heat of Water, or gallons x 1
b=strike water temp
C=Specific Heat of Mash, or A+B
c=desired mash temp

rearanged

(Cc-Aa)/B=b

I use intuition and previous experience.

Seriously, I think that formulas and the like are no substitute for knowing your system. I have not missed a mash temp since my first mash on my system.

77c on 5-6kg gives me 68c.

According to that formula, 421 = 462.

But I use the strike water to warm the mash tun as well as the grain, and just in case I screw up (which I sometimes do a little bit), I have an extra gallon each of hot and cold water to make minor adjustments.

I agree with Sonvolt that knowing your system is the only way to get it dialled in.

-a.

Palmer's book.

ajf said:

According to that formula, 421 = 462.

But I use the strike water to warm the mash tun as well as the grain, and just in case I screw up (which I sometimes do a little bit), I have an extra gallon each of hot and cold water to make minor adjustments.

I agree with Sonvolt that knowing your system is the only way to get it dialled in.

-a.

Click to expand...

How do you figure that? I think your doing something wrong. It gives me 172.1°F for 158°F mash, 70°F ambient temp, 2.8gal of strike water, and 9lbs of grain. Thats seems pretty close to what most people are doing. The advantage is you can raise or lower the strike temp for cold and hot weather and adjusting your mash temp. Its about 5° for a low in Missouri and the last time a had a chance to brew its was getting up to 90° in the day.

=((((lbsGrain*0.05)+StrikeVolume)*MashTemp)-(lbsGrain*0.05)*AmbientTemp)/StrikeVolume

Beersmith.

Another vote for BeerSmith - but last time, I was off by four degrees, so I'll adjust accordingly (first time with the new gear).

http://www.rackers.org/calcs.shtml

This works pretty good.

jcarson83 said:

How do you figure that? I think your doing something wrong. It gives me 172.1°F for 158°F mash, 70°F ambient temp, 2.8gal of strike water, and 9lbs of grain. Thats seems pretty close to what most people are doing. The advantage is you can raise or lower the strike temp for cold and hot weather and adjusting your mash temp. Its about 5° for a low in Missouri and the last time a had a chance to brew its was getting up to 90° in the day.

=((((lbsGrain*0.05)+StrikeVolume)*MashTemp)-(lbsGrain*0.05)*AmbientTemp)/StrikeVolume

Click to expand...

Aa+Bb=Cc

A=Specific Heat Grain, or lbs x .05
a=grain temp
B=Specific Heat of Water, or gallons x 1
b=strike water temp
C=Specific Heat of Mash, or A+B
c=desired mash temp

9 lbs grain * 0.05 = A
grain temp = 68 F = a
2.25g strike water = B
water temp = 192 = b
A + B = 2.7 = C
mash temp = 156 = c

(0.45 * 68) + (2.25 * 192) = 462 = Aa + Bb
2.7 * 156 = 421 = Cc

If Aa + Bb = Cc, then 462 = 421.
Q.E.D.

If I warmed up the cooler I use for a mash tun prior to mashing, then I would get different figures but I don't. Any calculation that fails to take account of the thermal mass of the tun cannot be correct for all equipment.

-a.

Promash