Mash Tun Temp Help

[DamageCT]

Hi all, I've been brewing for close to four years and feel it's about time to consider an upgrade. The pressure point currently for me tends to be hitting the correct temperature in the mash tun.

I have a 10 gallon gatorade cooler that I normally preheat with 180 degree water (that litterly drops to 140 when poured into the cooler) and then I reheat the water and pour it at "striking temp" on top of the grains. The past two times I've hit an issue with this where, even at striking temp, I'm hitting 10-20 degrees short on mash temps and need to reheat the now grainy water in my boiling pot and re-add. This problem doesn't always happen but appears to be an issue with my cooler's insulation randomly sucking out heat from the water.

I have been looking into a stainless steel or keg mash tun and lauter tun with either a HERMS or RIMS system. In your experience which works better, are they worth the upgrade?

All around how can I ensure I will hit the correct temps without the random absorption of heat from my cooler's insulation?

 

[rmyurick]

Maybe pour a quart or two of boiling water in to pre-heat the cooler? Leave it in until your mash water is ready & then just dump it.

Maybe you are losing heat through the lid? Try putting a folded blanket on top of the cooler lid.

 

[DamageCT]

I pour like an entire three gallons in at like 180 leave it for like 10-15 minutes with the lid on, pour it back into the boiling pot, and heat that water to accurate striking temp and then add the water back to the preheated mash tun with grains in it.

The temp drop tends to be right when it hits the grain and mash tun (I've checked accurate striking temp on three or four different calculators to make sure).

I can test the quart or two idea but to get from the 140 the water drops to from preheating the insulation to the 160-170 range the striking would be at takes only a few minutes and I would not expect that substantial of a preheat loss during that amount of time.

 

[BlueHouseBrew]

You don't need a HERMS or RIMS to hit your strike temp perfectly.

I do this:
(1) Fill HLT with about 3 or 4 gallons more than your strike volume;
(2) Heat HLT to a few degrees above desired strike temp;
(3) Fill MT to about 1 gallon more than strike volume;
(4) Keeping this fill level in the MT, circulate water from MT though HLT (applying heat to HLT as needed) and back to MT until the water in the MT is steady at the desired strike temp;
(5) Stop recirculation and drain MT to desired strike volume;
(6) Make any salt and/or acid additions to the water in the MT; and
(7) Dough in.

Presently, I pump water from the HLT to the MT and allow gravity to drain the MT to the HLT. Before I had a pump, I did this with gravity from the MT to the HLT and with a large scoop to bring water from the HLT to the MT.

Hope this helps.

 

[ColdbreakBrewing]

Maybe pour a quart or two of boiling water in to pre-heat the cooler? Leave it in until your mash water is ready & then just dump it.

I would advise against that . You'll warp/buckle the cooler walls. I personally wouldn't go much beyond 180ºf.

 

[wilserbrewer]

To preheat your MT, just add your all strike water 10-15 degrees above strike temp and allow it to cool to your strike temperature, stirring speeds this if you are over strike temp. Lots of folks do it this way w/ success. Adding a small quantity to preheat is a waste of effort IMO, add it all over the desired temp and let it acclimate down.

 

[Gameface]

I'm pretty confused by this issue.

There isn't anything random happening here.

Preheating the mash tun should help but really you could strike in without preheating and do just fine.

In my 10G round cooler I fill it completely with 120F water from my hot water tap and let it sit there while I get everything else ready. The water is 120F when I dump it.

I heat my 6G of strike water to (obviously it varies according to my recipe but typically...) 164F. Add it to mash tun, add ~22lbs crushed grain, stir, check temps, 150F. No random heat loss. Cover and let sit for 60min undisturbed. At the end of 60 min I've lost about 1F.

Please tell us in greater detail what you're doing. Is it possible your cooler has poor insulation and/or the insulation is water logged?

Are you accounting for grain temp when figuring your strike water temp?

I think you'll get better preheating using hot tap water and filling completely than you will adding a few gallons of hotter water, fwiw.

 

[Jupapabear]

It seems like you may not be considering the temperature of the grain. When you dough in the temp of the grain will drop, and ideally, you are aiming for it to drop to you precise mash temp.

 

[DamageCT]

Yes I am accounting for the grain temp and doughing in. My strike temps are about 15-20 degrees higher than my mash temps.

For example. Yesterday I preheated the mashtun using 180 degree water. I then left it to sit for about 15 minutes. I then went and poured this water back into the boiling pot (one pot with a heating element currently).

Next I heated the water to 166 degrees, striking temp, poured it over to the pre-heated mash tun to dough in, then bam, some of the heat had to of absorbed into the insulation, because the 166 degree water was now 140 degrees with 10lbs of grains that were 70. This should have dropped around 14 degrees, not 26.

 

[wilserbrewer]

I would suggest getting the strike water a constant temp in your cooler and then adding grain to water, rather than the opposite. Lots and lots of folks use the 10 gallon beverage cooler in this fashion without trouble.

I think you are losing a lot of heat during the transfer of your strike water.

Try heating your strike water to 175 - 180 and additn it to the MT and allow to sit 10-15 minutes, then stir or add a few ice cubes to dial in teh proper strike temp....around 162 plus minus....

 

[acidrain]

Pouring it back and forth is killing the stabilized heat in the mash tun.
Do like Wilserbrewer said... heat the liquor way over your strike temp. pour the measured strike water into the the MT and allow to cool until perfect strike temp is reached.
How are you calculating your strike temp? Are you actually measuring the temp of your grains before strike?
A pre-heated tun, measured amount of strike water, weight and temp. of grains entered into any of the on-line calculators works perfectly for this.

 

[blizz81]

I pour like an entire three gallons in at like 180 leave it for like 10-15 minutes with the lid on, pour it back into the boiling pot, and heat that water to accurate striking temp and then add the water back to the preheated mash tun with grains in it.

As a general process idea, I would probably advise doughing in by going water then grain, versus grain then water.


It's weird that it "doesn't happen every time" - generally I would say the delta between strike water temp and mash target temp after dough-in is 1) one of those measurements that's better observed on each equipment profile separately vs. calculated by software and 2) something that will change as you know with temp of equipment and grains, but I wouldn't think it'd change much.


A lot of brewers are using the standard Igloo coolers, etc, successfully so I don't necessarily know that it's a "this or HERMS / RIMS" situation - if indeed there is some problem with your cooler, you could always buy another cooler and have a pretty cheap expense. I went RIMS and tried to justify it to myself on a number of "it makes sense to go ahead and spend this much $ to build this piece of equipment" pieces of rationale, but in the end, the main reason I'd say to go with either would be if you'd have fun building the system. Besides continuous recirculation doing a much better job of lautering than manually vorlaufing, I don't know that there's any real functional reason to go to either as people seem to have success holding temp in much cheaper vessels.

 

[DamageCT]

Yeah I might just rethink my whole process. It's worked for about 20 successful brews and two or three messed up mashes however that's two or three too many.

 

[srice]

Take a look here:
https://www.homebrewtalk.com/showthread.php?t=477747

I had issues getting to the proper strike temp as well. This system has solved that issue as well as removing the water preheat time from my brew day.

 

[Gameface]

Yeah I might just rethink my whole process. It's worked for about 20 successful brews and two or three messed up mashes however that's two or three too many.

It worked 20 times and now isn't working? Something has changed.

Is the insulation in your cooler MT waterlogged?

 

[DamageCT]

Yeah its worked roughly 20 times, (four years of use), how would I check for waterlogging?

 

[DamageCT]

Someone on reddit mentioned using a bucket heater, does anyone have experience using these to preheat the water?

 

[evsol]

I use a bucket heater in my cooler mash tun to heat up to strike temp. Always hit my mash temp with no issues. Put a blanket on top of the cooler and loose somewhere between .5-1 degree over 60-90 minute mash. The bucket heater works well and allows me to do other things while the water gets to strike temp.

 

[DamageCT]

The bucket heater might be the perfect route for me since apparently the pouring is creating huge temp drops in the atmosphere I brew in.

Are the bucket heaters safe for water that is in a plastic cooler and will be eventually consumed?

 

[eric19312]

Are you measuring the temperature of the grain when you calculate strike water temperature or going based on room temperature? It is possible that your grain is recently colder than you think.

 

[evsol]

Bucket heaters are meant for livestock. I have had no off flavors. A bucket heater is basically a shielded hot water element much like the heat sticks that people use.

 

[jwalker1140]

Given that your system/process gave consistent results 20 times and then suddenly changed makes me also think something is up with your cooler. Look for small cracks in the plastic or leaks around your bulkhead. If it were me, even if I couldn't spot an obvious problem, I probably would just buy a new cooler before I would decide to overhaul my process.

Fwiw, this is my process for 5 gal batches using a 10 gal cooler:

-Heat mash water to 17F above target mash temp
-Add mash water to cooler and cover for 15 minutes (temp will have dropped ~7F after 15 minutes)
-Add grains to mash water, stir (temp will have dropped ~10F and should be at target mash temp)
-Top mash w/ aluminum foil to help retain heat, put lid on and start mash timer
-Temp will have dropped ~1F after a 60 min mash

 

[acidrain]

Are you measuring the temperature of the grain when you calculate strike water temperature or going based on room temperature? It is possible that your grain is recently colder than you think.

He won't or can't answer the question.

 

[Gameface]

He won't or can't answer the question.

He has already said that he DOES compensate for grain temp.

 

[Gameface]

OP, I've been all grain brewing for about 5 years and I'm on my 3rd cooler. I now have an Igloo cooler but my first two were rubbermaid. When I clean my cooler I often let the water overflow. Anyway, with the rubbermaid coolers it seemed like they'd get heavier and there was a gap where water could get into the insulation. I never changed them specifically for being waterlogged but I think they did get some moisture in there. I changed them when I failed to clean out the tun immediately after use and the grain went rancid.

The Igloo cooler doesn't seem to be prone to this issue, fwiw.

As another poster mentioned, before going HERMS or RIMS (I'm actually 90% ready to go on my kal clone eHERMS) change out the cooler and see if that's the issue. Personally I think one way or another that's your issue. There has been a change.

If it was a thermometer it would present itself differently. If you weren't accounting for this or that it would have happened in the first 20 batches. Same for technique (although I do think you should go water then grain). The insulated mash tun seems to be the heatsink here. I'd put money on it being directly related to an issue with your cooler.

Have you changed anything else at all about your process up to the point of striking in?