Missing mash temp after installing valve on HLT

[tre9er]

I think I know the answer to this, but wondered what you guys do in this case:

I just put a valve in my kettle (which acts as HLT and BK since I BIAB in a cooler). I heated my strike to a few degrees over what it should have been, drained into cooler, then doughed-in.

Missed my mash temp by almost 10 degrees. I think it's the fact that I'm no longer just pouring the strike water in, rather it's slowly draining into the cooler (which, yes, was pre-heated with hot tap water). Just seemed like a big loss.

Do you guys have some correction factor in your software to accomodate for this sort of heat loss or do you just heat way over strike temp and figure you'll stir down with lid off until the temp is right?

 

[Bobby_M]

The last thing you wrote.

 

[timdsmith72]

The last thing you wrote.

Yep. This.
Example: Saturday, I was mashing at 148 degrees. I calculated that my strike water needed to be ~158 degrees. I added 180 degree water to my mash Tun, closed the lid and let it sit for 5-10 minutes to pre-heat. Opened the lid and took a temperature reading. Then I stirred for a couple of minutes until the temp came down to ~161 and doughed in. I've discovered that it's easier to bring the temp down a bit than to raise it. After I doughed in, it was about 2 degrees high. A minute and a half to 2 minutes of stirring, and it came right down to 148 degrees.

Now, obviously, you will have to figure out how much high you need to shoot for using your equipment, but this is the general idea.
Hope this helps.

 

[tre9er]

Thanks. It's weird that in the past I've hit it right on the nose without stirring down and now twice I've been way low. I'm thinking 180 is probably the magic number and I like what you said about letting it sit to preheat it, rather than my way of filling with hot tap water (~120*) and hurriedly emptying, then filling with strike.

My efficiency was like 65% on this brew...pissed me off.

 

[dbrewski]

I brew 5 gallon batches in a cooler. I put the grain in first, heat 4 gallons to 170, and open the valve. It hits 152-154 like clockwork (My beers are mostly in the 1.045-1.06 range, so there is not a ton of variation in grain weight). No preheating of the cooler. [EDIT] I should add that my thermo on the HLT is very very low, I brewed with my buddy's equipment recently and hit 170 using his thermo placement (about 4-5 inches up) and I was way high on temp when I mashed. Which had the curious implication that the lower the thermo is, the hotter the water, even though heat rises. Or the more useful takeaway, the right temp for your system will vary.

 

[timdsmith72]

rather than my way of filling with hot tap water (~120*) and hurriedly emptying, then filling with strike.

Yes. It seems when the cooler gets hot it takes it a while to cool down. Seems to sort of work in reverse as well. Putting water in and then dumping it right back out won't heat it enough. It takes a little while for it to heat up.

 

[crazyirishman34]

Yeah I don't preheat my mashtun. I just input the thermal mass into beersmith and it gives me the correct strike temp. I pretty much hit my temps bang on.

 

[timdsmith72]

That's interesting. How do you calculate the thermal mass? Or did you just take the default?

 

[crazyirishman34]

Nope just put it on a scale and weight it. Then input the weight into the program.

 

[timdsmith72]

Ok thanks! I may give that a whirl!

 

[tre9er]

[EDIT] I should add that my thermo on the HLT is very very low, I brewed with my buddy's equipment recently and hit 170 using his thermo placement (about 4-5 inches up) and I was way high on temp when I mashed. Which had the curious implication that the lower the thermo is, the hotter the water, even though heat rises. Or the more useful takeaway, the right temp for your system will vary.

Especially since I use installed electric heating elements rather than any sort of burner.

 

[tre9er]

Yes. It seems when the cooler gets hot it takes it a while to cool down. Seems to sort of work in reverse as well. Putting water in and then dumping it right back out won't heat it enough. It takes a little while for it to heat up.

Sorry, I wasn't clear on this. I don't empty it soon after I filled it, but when I do finally empty it...I do it quickly so as not to lose heat.

 

[WhiteDog87]

I always make sure to have two different sources of water for doughing. I will add a majority of my water from one source that is around 170F and have a second smaller pot of water that is closer to 180F for bringing the temp up if it ends up too low, or I'll leave the top off the cooler and stir if I over shoot.