BeerSmith mash temps

[LovesIPA]

This drives me nuts.

BeerSmith just will not cooperate and give me the right strike water temp. I have a 10 gallon igloo cooler with a copper manifold. I am ALWAYS off by a few degrees, sometimes too hot, sometimes too cold but unlike the Goldilocks and the three bears, it has never been just right.

Today I mashed in 10 lbs and 2oz of grain and did/checked the following:

- "Adjust temp for equip" box checked
- Grain temp was set to 68 degrees
- Boiled about 3/4 of a gallon of water and dumped it into the mash tun to preheat it. I measured the temp of the water after letting the temp equalize and it was 180. That's what I put in BeerSmith as the mash tun temperature
- Mash tun specific heat is set to 0.30 (default) in my equipment profile
- Mash thickness is set to 1.5 qts/lb. It's been this way for about three batches now. I have a 5 gallon HLT and it's easier just to use a bigger mash volume so my sparge water all fits in one pot. This hasn't affected the problem at all - I've been struggling with this for a while now.
- Target temp was 150. I came in at 145.1. I use a thermapen to check mash temps.

Any ideas on what I'm missing?

 

[jdauria]

Are you take your mash temp as soon as you mash in? I pretty much have the same setup as you and usually hit my numbers within a degree one way or the other. But what I do after mashing in is to let it sit for 5 minutes to stabilize before taking the temp. When you enter your mash time and temps in BeerSmith, you can set the "rise" rest time.

Only other possible issues, grain temp could be off. Do you take a temp reading or just assume it's 68? The other question is after you preheat to 180, are you draining that water? If you are, then the cooler is probably less than 180 as it cools some during draining.

 

[LovesIPA]

I take the temp while I'm still stirring the mash. I stick the probe in and after about 30 seconds of hard stirring it's pretty stable.

I keep my grains inside the house and I look at the thermometer in the room where the grains are.

Yes I drain all the water out through the ball valve. I did pop the lid off long enough to dump the pint or so out, but I can't really believe that's throwing the mash temp off by 5 degrees.

 

[Matteo57]

I usually throw about 180 degree water into my mash tun for 10 minutes or so prior to the rest... dump that and then the strike water and grains. I have tun set at 120F. I have never measured temp in there, but it is always within a degree up or down. Probably should really check a bit more to be precise.... I also use brew365.com mash calc hand in hand between the two to double check things. Helps out

 

[jdauria]

Here's a question, is your thermometer calibrated? If you bring water to boiling does it read 212? If you add crushed ice and water and let sit for a few minutes and then take a reading is it 32F?

As I said, we have basically the same setup and I just brewed Sunday. My grain (with probe in middle of the sack) was 64.2, the cooler after adding hot water and draining, was 80.0 when holding the probe about inch from bottom of cooler. Mash temp was 152, BS called for 167.9F water..added that (more like 168F), and after letting the mash rest for 5 minutes, my temp was 152.9, just a degree off.

So it's either the thermometer or you are losing more heat when you drain the water then you think. Remember, that water is only taking several inches at bottom of the cooler, while the mash will take 3/4th or more of the cooler, so just because it's 180 in the water, the temp can be cooler above it as the 180 water tries to heat the 68 degree air in the rest of the cooler.

 

[LovesIPA]

Here's a question, is your thermometer calibrated? If you bring water to boiling does it read 212? If you add crushed ice and water and let sit for a few minutes and then take a reading is it 32F?

Ice bath: 32.1
Boiling water: 211.4

The barometric pressure is 29.83 today, which is a little short of standard 29.92, so that plus the margin of error puts it in range.

 

[IL1kebeer]

Did you put the correct "specific heat" for your equipment in the equipment profile?
Did you check the box "Adjust temp based on equipment" in the mash tab?

I have the same setup minus the manifold and my strike temps are spot on, sometimes 1 degree too high but that's an easy fix with a minute or so of stirring with the lid off.


Sent from my iPad using Home Brew

 

[LovesIPA]

Did you put the correct "specific heat" for your equipment in the equipment profile?
Did you check the box "Adjust temp based on equipment" in the mash tab?

Read the OP.

 

[jdauria]

Ice bath: 32.1
Boiling water: 211.4

The barometric pressure is 29.83 today, which is a little short of standard 29.92, so that plus the margin of error puts it in range.

Guess it's not the thermometer!

 

[LovesIPA]

It better not be! I spent enough on the damn thing.

 

[Oginme]

If you are off randomly, sometimes high and sometimes low, using the same equipment and mashing profile, then the problem is one of process control or consistency. Given that BeerSmith is a predictive software based upon the static profile inputs, I consider +/- a couple of degrees well within my process error/variability. Timing, exact temperature readings, consistent heating and stirring, ambient temperatures will all effect your results.