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General Category => All Grain Brewing => Topic started by: GarretD on October 02, 2017, 06:31:14 PM

Title: Mash temp drop
Post by: GarretD on October 02, 2017, 06:31:14 PM
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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Title: Re: Mash temp drop
Post by: denny on October 02, 2017, 06:37:54 PM
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.
Title: Mash temp drop
Post by: GarretD on October 02, 2017, 06:41:24 PM
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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Title: Re: Mash temp drop
Post by: denny on October 02, 2017, 06:47:39 PM
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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If the beer turns out the way you want it to, you don't have a problem.  Easy solution!
Title: Re: Mash temp drop
Post by: dmtaylor on October 02, 2017, 06:51:22 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.
Title: Re: Mash temp drop
Post by: GarretD on October 02, 2017, 06:51:53 PM

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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Title: Re: Mash temp drop
Post by: denny on October 02, 2017, 07:10:45 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. 
Title: Re: Mash temp drop
Post by: kramerog on October 02, 2017, 07:15:23 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.
Title: Re: Mash temp drop
Post by: Stevie on October 02, 2017, 07:16:11 PM
SWAG - your mashtun is sucking the heat out. What is the temp a few minutes after you mash in?
Title: Re: Mash temp drop
Post by: Stevie on October 02, 2017, 07:16:56 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.
Title: Re: Mash temp drop
Post by: GarretD on October 02, 2017, 07:29:21 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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Title: Re: Mash temp drop
Post by: HoosierBrew on October 02, 2017, 07:32:46 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.
Title: Re: Mash temp drop
Post by: gs650gtd on October 02, 2017, 08:25:31 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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Title: Re: Mash temp drop
Post by: scrap iron on October 03, 2017, 01:04:27 PM
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.
Title: Re: Mash temp drop
Post by: Visor on October 03, 2017, 03:51:16 PM
   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.
Title: Re: Mash temp drop
Post by: denny on October 03, 2017, 03:56:59 PM
I used to preheat my mash tun until I realized it was another step I could avoid and save time and effort.  I just figured out how much hotter my strike water had to be to hit mash temp without preheating.  I've done that for many years and hundreds of batches now, and al;ways hit my strike temp right on.
Title: Re: Mash temp drop
Post by: HoosierBrew on October 03, 2017, 04:27:18 PM
I used to preheat my mash tun until I realized it was another step I could avoid and save time and effort.  I just figured out how much hotter my strike water had to be to hit mash temp without preheating.  I've done that for many years and hundreds of batches now, and al;ways hit my strike temp right on.


Same here, Denny. If I bring my cooler in from the garage a day or two before brewing to equalize with house temps, I get a pretty reliable strike temp differential from whatever the target is. Lots of ways to get there though
Title: Re: Mash temp drop
Post by: denny on October 03, 2017, 04:34:59 PM
I used to preheat my mash tun until I realized it was another step I could avoid and save time and effort.  I just figured out how much hotter my strike water had to be to hit mash temp without preheating.  I've done that for many years and hundreds of batches now, and al;ways hit my strike temp right on.


Same here, Denny. If I bring my cooler in from the garage a day or two before brewing to equalize with house temps, I get a pretty reliable strike temp differential from whatever the target is. Lots of ways to get there though

I leave mine in the garage all the time, knowing that if I heat to 12-14F above my mash temp I'll be right on.
Title: Re: Mash temp drop
Post by: Kevin on October 03, 2017, 04:47:17 PM
Do you measure the temperature of your grain before you start? It makes a difference.
Title: Re: Mash temp drop
Post by: ynotbrusum on October 04, 2017, 04:31:36 PM
Maybe the opening of the mash tun multiple times/for an extended period of time may have more to do with the temperature drop than the vessel, itself?
Title: Re: Mash temp drop
Post by: brewinhard on October 04, 2017, 06:32:44 PM
Maybe the opening of the mash tun multiple times/for an extended period of time may have more to do with the temperature drop than the vessel, itself?

This^^^^?
Title: Re: Mash temp drop
Post by: Philbrew on October 04, 2017, 07:47:34 PM
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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On some coolers, sometimes water/wort can seep into the cooler's insulation space via a poor seal at the valve and cause ineffective insulating.  Pull the valve and check for liquid in the insulation space.

Also the cheaper orange Igloo coolers are not insulated as well as the spendy yellow ones.
Title: Re: Mash temp drop
Post by: syncopadence on October 10, 2017, 10:29:43 PM
Yeah that's quitea drop. I'd be looking for cracks/openings on your mash tun. I used a rectangular cooler for a while and it held temp great.

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