Author Topic: Mash temp drop  (Read 2093 times)

Offline GarretD

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Mash temp drop
« on: October 02, 2017, 11:31:14 AM »
My target mash temperature was 152 for my last 2 batches. Hit it right on for the first 10 minutes. At the 30 minute mark I'm down to 146. I'm using an 10 gallon igloo cooler, 5 gallon batches. Ive been adding2-4 quarts of 170 water to bring temp back up to 152. My question is it even needed? Is that an acceptable drop? Or should I be adding it even earlier to keep it right at 152 for the whole mash.


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Offline denny

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Re: Mash temp drop
« Reply #1 on: October 02, 2017, 11:37:54 AM »
That does seem like quite a drop.  My rectangular cooler only loses maybe 1-2 F over the course of a 60-90 min. mash.  You may have too much headpsace which is causing the cooldown, but I have a lot of headspace in my cooler that doesn't seem to be a problem.  Have you tried something easy like putting a blanket or sl;eeping bag over the cooler?  I don't think the temp drop is too much of a problem, but it would be nice to figure out what's doing it and try to prevent it.
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Offline GarretD

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Mash temp drop
« Reply #2 on: October 02, 2017, 11:41:24 AM »
I'm brewing right now, seems like there is maybe 8" of head space. I'll try to wrap it next time. Last batch had same problem, missed projected OG by just a hair, so I wasnt to concerned.


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« Last Edit: October 02, 2017, 11:44:33 AM by GarretD »
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Offline denny

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Re: Mash temp drop
« Reply #3 on: October 02, 2017, 11:47:39 AM »
I'm brewing right now, seems like there is maybe 8" of head space. I'll try to wrap it next time. Last batch had same problem, missed projected OG by just a hair, so I wasnt to concerned.


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Online dmtaylor

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Re: Mash temp drop
« Reply #4 on: October 02, 2017, 11:51:22 AM »
The drop to 146 F doesn't even matter in my experience.  I've brewed many dozens of batches that way and they come out just fine.
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Offline GarretD

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Re: Mash temp drop
« Reply #5 on: October 02, 2017, 11:51:53 AM »

If the beer turns out the way you want it to, you don't have a problem.  Easy solution!
[/quote]

Still new to all grain and figuring out what is crucial and what can slide. Also trying to improve my brewing and efficiency. Thanks for the help


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Offline denny

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Re: Mash temp drop
« Reply #6 on: October 02, 2017, 12:10:45 PM »
The drop to 146 F doesn't even matter in my experience.  I've brewed many dozens of batches that way and they come out just fine.

In general I agree with ya. 
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Offline kramerog

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Re: Mash temp drop
« Reply #7 on: October 02, 2017, 12:15:23 PM »
Garrett, my strike water temperature is often about 6 F hotter than the desired mash temperature to compensate for grains being much cooler than the mash temperature.  Are you using a strike water calculator to determine how hot your strike water (water for first infusion mash) should be?

I didn't use a strike water calculator for my first all-grain batches and my mash temp was off.

Offline Stevie

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Re: Mash temp drop
« Reply #8 on: October 02, 2017, 12:16:11 PM »
SWAG - your mashtun is sucking the heat out. What is the temp a few minutes after you mash in?

Offline Stevie

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Re: Mash temp drop
« Reply #9 on: October 02, 2017, 12:16:56 PM »
Garrett, my strike water temperature is often about 6 F hotter than the desired mash temperature to compensate for grains being much cooler than the mash temperature.  Are you using a strike water calculator to determine how hot your strike water (water for first infusion mash) should be?
He and I are on the same though track.

Offline GarretD

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Re: Mash temp drop
« Reply #10 on: October 02, 2017, 12:29:21 PM »
I preheated the mash turn, cooler, with some 170 water then dumped it. Used a strike water calculator and added 15q of 168 degree water. Temp was 154 right away and 152 after stirring. It held at 152 for about 10 minutes then started to drop.


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Offline HoosierBrew

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Re: Mash temp drop
« Reply #11 on: October 02, 2017, 12:32:46 PM »
Is your thermometer reliable and calibrated? Pretty much any cooler shouldn't lose 6 degrees F in that space of time. Like Denny, I  lose maybe a couple dF max in a 60 minute cooler mash.
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Offline gs650gtd

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Re: Mash temp drop
« Reply #12 on: October 02, 2017, 01:25:31 PM »
Hi,I use a 52 litre rectangular cooler converted and loose less than 1°c over an hour.
As suggested in previous posts try a sleeping bag to insulate as it seems you may have an air leak on your lid as it does seem to be a progressive loss.

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Offline scrap iron

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Re: Mash temp drop
« Reply #13 on: October 03, 2017, 06:04:27 AM »
I was going to suggest preheating MT but someone mentioned that. Maybe try hotter preheat and place a piece of aluminum foil on top of the liquid and make sure lid is on good.
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Offline Visor

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Re: Mash temp drop
« Reply #14 on: October 03, 2017, 08:51:16 AM »
   How much water are you using to preheat your mash tun? I batch sparge and use my full volume of boiling sparge water to preheat my round cooler, my thermal loss is usually less than 2 degrees over an hour.
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