Hot water additions failing to get even close

[sideshow_ben]

I'm doing my second step mash today and have checked a variety of calculators to find the approximate amount of boiling water to add to my mash to raise it to the next step. And the water amounts are so far off it makes me curious if other people find that they work.

I have a 10-lb grain bill for which I did a protein rest at 122 for 20 min. The ending temp was 123. I added 2.5 gal of boiling water and had to add a full gallon further just to hit 155 F. I then tried to mash out at 168 and added 2.5 gallons of boiling water and only made it to 164. According to all the calculators I found, I only needed 2.5 gal of boiling water for the first raise, and 1.25-1.5 gal for the 2nd. So....this guy is very confused. BTW my cooler is really awesome at holding on to heat and usually drops less than 1 degree in a 1-hr mash.

-ben

 

[slakwhere]

do you have an IC by any chance? and a pump?

 

[user 19629]

I have never hit my mashout temp by infusing the amount of water that the software says to add. I don't care to much about the mashout. But it's one of the reasons I have been hesitant to try a step mash.

 

[alan_marks]

Quick question, what water to grain ratio are you using to base your calculations? Using 1 qt water per pound as a basis, ProMash calculates you would only need 7.2 qts of boiling water to raise a 10 lb mash from 122F to 155F. This is also assuming that your grain temperture to start is 68F and you heated your 10qts water for doughing in to 140F to hit your 122F protein rest. I am also assuming a preheated mash tun and a 0.3 coefficient for thermal mass.

Alan

 

[lumpher]

i never worry about exact mash-out temps. mash-in, yes, i'm a stickler for 152-154, normally. out? i try to get 168, but if i miss it, o well

 

[sideshow_ben]

Alan, I used 1.25 qt/lb today.

 

[sideshow_ben]

do you have an IC by any chance? and a pump?

Chiller yes, pump no. But I see where you are going. can one pick up an appropriate pump without selling organs?

 

[Northcalais40]

The fact that your MLT is awesome at holding temps implies that it has a lot of Thermal mass (sorry for the bogus science terms, it's early). You need to add enough water to raise the mash, and the mash tun, to the desired temp. You can use the numbers you posted to back out the difference between what the chart tells you to do, and what your set up actually requires you to do.

I don't have the math at the tip of my brain, but check out the various sites that explain infusion temps (Braukaiser.com is a good go to ). You can add a coefficient to the equation that fudges for the mass of the tun.

Sorry, not very clear perhaps.

 

[slakwhere]

Chiller yes, pump no. But I see where you are going. can one pick up an appropriate pump without selling organs?

i bought one of these and have been very happy with it. it allows me to go HERMS using my IC and HLT. that makes sure i always hit all my temps, weather single infusion or step. it's also great for moving liquids. the only thing i ever lift while it's full of liquid is my carboy(s)... and if i would brew closer to the garage door then i guess i could just pump everything into the carboy in the ferm chamber when i was done

 

[alan_marks]

I've taken the liberty to try to come up with a mash schedule based on what information you've given so far using the mash designer in ProMash. I hope this gives an idea or two.

Alan

Mash Name: two rest step mash
Total Grain Lbs: 10.00
Total Water Qts: 12.50 - Before Additional Infusions
Grain Temp: 68.00 F
Tun Thermal Mass:0.40
Step Rest Start Stop Heat Infuse Infuse
Step Name Time Time Temp Temp Type Temp Amount Ratio

protein rest 5 20 122 122 Infuse 140 12.50 1.25
sachh. rest 5 30 155 155 Infuse 210 8.70 2.12
mash out 5 30 168 168 Infuse 210 7.18 2.84

Total Water Qts: 28.38 - After Additional Infusions
Total Water Gal: 7.10 - After Additional Infusions
Total Mash Volume Gal: 7.90 - After Additional Infusions
All Step/Rest temperatures are in degrees Fahrenheit
All Infusion amounts are in Quarts.
All Infusion ratios are Quarts/Lbs.

 

[ghpeel]

I have never hit my mashout temp by infusing the amount of water that the software says to add. I don't care to much about the mashout. But it's one of the reasons I have been hesitant to try a step mash.

Me too, but my efficiency seems OK and the beer has been fine, so I don't sweat it too much.