Mash temp questions

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HollisBT

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So I am partway through a brew day, sparging at the moment, and I am getting a bit frustrated with my mash...

My target mash temp was 150 degrees, which I missed by slightly over 3 degrees, I decided to RDWHAHB and just let it go forward. 90 minutes later and it comes time to lauter and sparge, I decide to check temps again, over the course of an hour and a half apparently I lost about 7-8 degrees in the tun, leaving with a final resting temp of 140 degrees... I am not overly happy with this.

Now, my question is this: How should I set up my brewing software so that in the future I do not have this issue. My strike water temperature was spot on, or so I thought, so I lost about 3 degrees with the dough in. Should I incorporate that 3 degrees into my strike water temp? How worried should I be about the temp loss over the course of the mash? Should I aim to make my mash higher, or are the temps at the beginning of the mash more critical than the temps at the end of the mash?

I am trying to not worry about it too much, but my past two brews did not finish the way I was wanting them to, and I really want this brew to kind of boost my brewing confidence haha.
 

kh54s10

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There are two things that I can think of.

1) are you preheating your mash tun?

2) If yes and you are losing 6-8 degrees you can compensate by starting a little warmer.

How to do that with your software would be different depending on which program.
 
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HollisBT

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When I mash I add the hot liquor to the tun, then add the grist to dough in. So the tun is somewhat pre-heated, but I somewhat disregaurd that temp since I somewhat assume the software has accounted for it. But looking back, I should have paid a bit more attention to it on this brew.

Perhaps next brew day I should set my mash tun temp loss to 0 degrees, overheat the water, and then dough in when the water temp is correct for the mash temp after heating the grains?

The software that I am using is iBrewmaster for the ipad.
 

postal_penguin

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What are you mashing in? I lose about 2 degrees F when I do BIAB with just a wool blanket wrapped around the aluminum pot. 7-8 degree loss seems like poor insulation or you are stirring/opening it too often.
 

MrOrange

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If you have a cooler type mash tun you might want to try covering it with a thick blanket to try and hold in as much heat as possible. Don't worry about confidence, everything is trial and error. Your becoming a better brewer every time you brew even if you make mistakes. Trust me I know, I have had several brews that did not turn out how I thought they would but I learned a little about my system every time.
 
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HollisBT

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The mash tun is a 10 gallon cooler, and I only opened it to stir/check temp twice. Once at the beginning of the mash, and again at the end...

I guess I need more trial and error with hitting my mash temps and keeping the temp. More practice means more homebrew, right? :)

That, and I think I need to start taking better notes. It is just getting frustrating trying to get this equipment figured out so I can start getting accurate and consistent brew days...
 
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HollisBT

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And just in case anyone was wondering, I actually did RDWHAHB, noon on a Wednesday and enjoying a homebrew. Can't complain about that!
 

QuaffableQuips

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Also, how long after mashing in did you measure your initial temperature of 147-ish? I usually wait 5-10 minutes for the temperatures to stabilize, particularly this time of year. I store my grain in the garage, so it's usually considerably colder than room temperature. It takes a while for the temperature to settle down.

All this to say that if you took the temperature within 5 minutes of mashing in, you might not have caught it at equilibrium.

I use a cooler, and the process I've settled on is to always pre-heat my tun and then adjust the strike water temp depending on the grain temp (which I measure while I heat the strike water). Usually I can get it to within +/- 2 degrees of my intended temp, which is accurate enough for me.
 
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HollisBT

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I took the initial temp about 10-12 minutes after doughing in.

What is your process for pre-heating your tun? Also, I took my grains out last night and let them stabilize to house temp, which is about 68.
 

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The mash tun is a 10 gallon cooler, and I only opened it to stir/check temp twice. Once at the beginning of the mash, and again at the end...

I guess I need more trial and error with hitting my mash temps and keeping the temp. More practice means more homebrew, right? :)

That, and I think I need to start taking better notes. It is just getting frustrating trying to get this equipment figured out so I can start getting accurate and consistent brew days...
I let the hot water run as I begin to get my supplys and equipment set up. Then I fill up my cooler/mashtun w/the hot tap water as I go on w/the rest of my set up. I heat my strike water to about 8* above what I want to mash with. When I reach that temp I quickly empty the cooler and pour in the strike water and cover.

I BIAB so I then put in the bag and add the grain mixing as I pour. 15 min into the mash I check the temp and it's usually a degree or two above what I want, but at 30-45 & 0 minutes it's spot on and I mix every 15 minutes.
 

mthompson

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To hit your numbers you need to:


  • [1]Know weight of grains
    [2]measure the temperature of the grains (I store overnight in the same spot I measure, and leave them there after so this doesn't change much)
    [3]calculate strike volumes/temps based on the above and the thickness you want
    [4]heat water up 10*F past the strike temp
    [5]dump water in mash tun, and let it preheat for 10 minutes or so

This will usually result in water in the mash tun a degree or two warmer than what you want to strike. There are many ways to cool it off the last few degrees. Depending on how close I am. Pretty close and I'll simply dip some water out and pour it back in from a foot or two above the tun, as this cools that bit of water just a little at a time. For 5 degrees or more, I'll pull a known volume out (2 cups) and replace it with the same amount of colder water and then stir and let sit a minute to equalize. Check temp and repeat till close, then use the first method.



  • [6]dough in your grains, and stir a bunch
    [7]place lid on and wait 5 minutes
    [8]check mash temp in several spots

I did a 90 minute mash last week, 40*F outside, in a 10 gal cooler and I only lost 2*F while stirring three times. So my guess is, you mashed in before your tun was heated fully and measured your initial mash temp too soon.

Hope that helps,
 

QuaffableQuips

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I took the initial temp about 10-12 minutes after doughing in.

What is your process for pre-heating your tun? Also, I took my grains out last night and let them stabilize to house temp, which is about 68.
I think 10-12 minutes should be long enough. It is on my system anyway.

My pre-heating method isn't the most environmentally efficient, but it's predictable. I heat about 2 qt of water on the stove to boiling. While it's heating up, I fill my tun with about 2 gallons of the hottest water my kitchen faucet can produce. Once the water boils, I add that to the tun, close the lid, and let it sit while I mill the grain and heat my strike water. By the time my strike water is ready, the tun is warm enough. I just set my mash tun temp to 70 F in BeerSmith. This has worked for me, but every system is different.

Now, one other thing to consider is that if you're doing small grain bills in a 10 gallon tun, you might have to do more tweaking due to all that head space. Last time I brewed a bitter (OG 1.040, so only 6-7 lb of grain), I undershot my temp by about 5 degrees.
 
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HollisBT

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Thanks for the input guys, I will test some of these methods with upcoming brews.

One positive note about today's brew day: 77.25% efficiency out of the mash!!

Came out with a higher volume than expected (not sure how, maybe my grain absorption factor is high?), and a higher pre-boil gravity than expected.
 

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I just posted this, there should be a sticky! I went from 5 degrees an hour to almost no loss at all in 90 minutes with a 2/3 filled MT. Also, this is brewing outside in 40 degrees with no blankets or anything wrapping it.

"I insulated my round cooler lid to try and get better temp holding. Didn't work worth beans. BUT, I was tipped off that the real temp losses are in the headspace. You make a 2" foam "lid" that friction fits inside the cooler, cover it in aluminum foil and aluminum tape or just all aluminum tape. Slide it in just on top of the mash, dont compress it, just slide it on top of the mash. You'll hold temps so close for so long you'll be shocked. Obviously this is far easier with a round cooler vs. a rectangular."

Don't forget to make some kind of a handle to get it out of the MT. I doubled a piece of aluminum tape back on itself and left enough on each end to stick it down. Also, If you have a thermometer with a probe, you can just shove it through the middle to punch a little hole and have a thermoport! We should call this thing a "false top".
 

edmanster

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I always heat my strike water to 180° to pre heat my MT... I wait 10 min and start adding 1-3 ice cubes every minute and stir to check temp.. It's tricky because it's alot easier to cool down water then to heat it up!! I use a old bed comforter and cover.. I did a over night mash before and only lost 4° after 6 hours...
 

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I usually heat my strike water 5-10 degrees above where I want it. Dump it into my cooler. Close it up and let it sit for 10 mins. This is preheating the mashtun. Then I dough in and stir for several mins check temps. If I'm too high, I add a little cool water until I get my desired mash temp, close cooler and cover with blanket. I usually do this part indoors during winter and the temp is the exact same when I check on hour later
 

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My hot water heater temp is about 130*, I set mash tun temp to that in beersmith.

Also I made a spread sheet to see temp loss over different grain loss. I think this is only needed till you figure out your system or have drastic changes in grain weight.

Also made another ss to track water loss to grain, boil and trub to help figuer the system. Got that part pretty well wired now.
 

ShaLaH

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I just posted this, there should be a sticky! I went from 5 degrees an hour to almost no loss at all in 90 minutes with a 2/3 filled MT. Also, this is brewing outside in 40 degrees with no blankets or anything wrapping it.

"I insulated my round cooler lid to try and get better temp holding. Didn't work worth beans. BUT, I was tipped off that the real temp losses are in the headspace. You make a 2" foam "lid" that friction fits inside the cooler, cover it in aluminum foil and aluminum tape or just all aluminum tape. Slide it in just on top of the mash, dont compress it, just slide it on top of the mash. You'll hold temps so close for so long you'll be shocked. Obviously this is far easier with a round cooler vs. a rectangular."

Don't forget to make some kind of a handle to get it out of the MT. I doubled a piece of aluminum tape back on itself and left enough on each end to stick it down. Also, If you have a thermometer with a probe, you can just shove it through the middle to punch a little hole and have a thermoport! We should call this thing a "false top".
Komodo,
Great Idea! I was going to put 2" Foam on the bottom of my Cooler Lid so that when I screw on the lid, there would be less headspace. But you took it to a new level. Putting a probe through the foam lid is a great idea.
Thanks
 
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