How do YOU keep your cooler mash-tun as close to temp as possible?

[BrewKaiser]

I appreciate forum discussions with lots of constructive ideas and support. I, too, have struggled with maintaining mash temps in my 5 Gal Gott MLT, but I am starting to realize/wonder that my anxiety to maintain mash temp over 60 min is born more from my competitive nature and tendency to conform to convention than based on what is really necessary.

FWIW, I too preheat my MLT to 110-120* with hot water while I bring my strike water to temp. This serves to give my HLT & MLT one more rinse and I use this time to prepare other steps or processes. I, too, keep grains inside close to 70* and wrap my MLT after dough in. Foil and Styrofoam seem like they would work well. I do agree that dough in should be done as quickly as possible. I also think overshooting strike water temp into MLT and allowing to cool to strike temp is a good idea as water will cool during transfer from HLT to MLT from hoses, air, and MLT absorbing some of the heat from the strike water.

My last brew day, I made a Nelson clone and pushed my MLT to it's limit with a fine mill and a thick mash. I intentionally overshot initial strike by 1*, but at 15 min intervals stirred and noticed rapid temp loss (1-1-1/2* every 15 min).

As Zymurgist suggested previously, and as demonstrated by the poster in the link below, conversion of today's modified grains actually takes place in the first 5-15 minutes of the mash assuming proper crush and water to grain ratio.

https://www.homebrewtalk.com/f244/mas...5/#post6750563

The real issue regarding maintaining mash temp, as I see it, is not about fully converting starches to sugars to hit predicted OG targets, but breaking down the correct sugar branches to hit target attenuation and FG while still obtaining the right body and flavor for a given recipe. So the question I'm struggling with, after the first 15 minutes at target temp, what is happening the remaining 45 min during mash, and how necessary is this to conversion, flavor, and body?

More and more, I am beginning to question the time my typical brew day takes and looking for ways to be both more efficient while reducing time for certain steps. I think the first 15 minutes of Mash temp is crucial, but the remaining time is just there to vex our never ceasing desire to tinker and fuss over 1* to 2*.

I also have struggled with reliability of thermometers. I have 5 different thermometers (2 digital, 2 glass, 1 bimetal) having calibrated the digital and bimetal. I have done tests where all 5 report different temp +/- 2-3* at various temp ranges. So here is another variable where despite my need to control, I am at the mercy of my equipment. Don't know if I can justify the $100 for the Thermopen, which is supposed to be the best. Don't know if $100 investment would even matter...

 

[pwnshop]

1. i heat my strike water to around 175-180 then pour it in my mash tun and close the lid. I let it sit for a while to preheat.
2. Then i open the lid and stir the water around until it settles at a degree or two above what beersmith tells me my mash in temp is.
3. mash in and stir until I am at my mash temp
4. Then i put a piece of aluminum foil on the grain bed. Close the lid and cover with a blanket.

My cooler is a typical run of the mill cooler that I bought off craigslist for 15 bucks. The lid is hollow and not insulated, in fact it has a little door built in to the lid that you can use to reach in and grab a brew.

I don't even lose a degree over a 60 minute mash this way.

 

[azazel1024]

I BiaB and mash directly in my kettle. Heat the water to temp, mash in, double check I am at the proper mash temperature. In the winter time or anything below about 70F, I'll cover the whole thing with a thick towel. Generally every 20 minutes for the hour I stir it up and kick the burner back on for 60 seconds.

This generally seems to keep the temperature within about 2F of what I am looking for. In the summer time I don't even bother to cover it up. In the sun and with temps of 80+F, If I kick the burner on once for a minute during an hour mash it generally stays within 1-2F.

Of course in the dead of winter brewing in my garage there are times I cover it up and if I forget about it for half an hour because I am busy doing other things, I can come back and it has dropped 5-6F and I have to fire the burner for 2-3 minutes stiring it up to get it back to the proper temperature.

I generally take the temp loss in to account, so I'll tend to mash high by 2F or so in the winter time, because I know it might drop from, say, 154F to 150F in 20-30 minutes covered up, before I kick it back up to temp.

 

[azazel1024]

I appreciate forum discussions with lots of constructive ideas and support. I, too, have struggled with maintaining mash temps in my 5 Gal Gott MLT, but I am starting to realize/wonder that my anxiety to maintain mash temp over 60 min is born more from my competitive nature and tendency to conform to convention than based on what is really necessary.

FWIW, I too preheat my MLT to 110-120* with hot water while I bring my strike water to temp. This serves to give my HLT & MLT one more rinse and I use this time to prepare other steps or processes. I, too, keep grains inside close to 70* and wrap my MLT after dough in. Foil and Styrofoam seem like they would work well. I do agree that dough in should be done as quickly as possible. I also think overshooting strike water temp into MLT and allowing to cool to strike temp is a good idea as water will cool during transfer from HLT to MLT from hoses, air, and MLT absorbing some of the heat from the strike water.

My last brew day, I made a Nelson clone and pushed my MLT to it's limit with a fine mill and a thick mash. I intentionally overshot initial strike by 1*, but at 15 min intervals stirred and noticed rapid temp loss (1-1-1/2* every 15 min).

As Zymurgist suggested previously, and as demonstrated by the poster in the link below, conversion of today's modified grains actually takes place in the first 5-15 minutes of the mash assuming proper crush and water to grain ratio.

https://www.homebrewtalk.com/f244/mas...5/#post6750563

The real issue regarding maintaining mash temp, as I see it, is not about fully converting starches to sugars to hit predicted OG targets, but breaking down the correct sugar branches to hit target attenuation and FG while still obtaining the right body and flavor for a given recipe. So the question I'm struggling with, after the first 15 minutes at target temp, what is happening the remaining 45 min during mash, and how necessary is this to conversion, flavor, and body?

More and more, I am beginning to question the time my typical brew day takes and looking for ways to be both more efficient while reducing time for certain steps. I think the first 15 minutes of Mash temp is crucial, but the remaining time is just there to vex our never ceasing desire to tinker and fuss over 1* to 2*.

I also have struggled with reliability of thermometers. I have 5 different thermometers (2 digital, 2 glass, 1 bimetal) having calibrated the digital and bimetal. I have done tests where all 5 report different temp +/- 2-3* at various temp ranges. So here is another variable where despite my need to control, I am at the mercy of my equipment. Don't know if I can justify the $100 for the Thermopen, which is supposed to be the best. Don't know if $100 investment would even matter...

I've done very, very basic calibration checking on my candy thermometer that I use. It seems to be within around 1F at boiling temperatures (It reads 212.3F, but at my altitude it should be about 211F)) and about 2F at freezing (ice water reads about 34F). I figure that is close enough. I've only checked it once since I initially checked it (maybe 9 months after the fact?) and it seems to be more or less holding at that.

So, until the thing breaks, I'll periodically check its calibration maybe once a year to make sure I am not starting to get a large drift. Then, I figure meh, if it is off by a degree or two, no big deal. The fact that I am using it for everything brewing is all that really matters.

On the fermentation side, I haven't bothered calibrating my ITC1000 and STC1000, but I DID compared the thermocouples of the two, they read within .2C of each other. Which is all that really matters to me, so that I know if I dial in one temperature on one of my minifridges, then I should be getting the same fermentation temperature as I would be on the other minifridge, within some tiny margin of error based on the differences in minifridges (3.5 vs 4.4cu-ft), but the actual temperature control should be doing the same thing.

 

[jparrette]

2 things about coolers as mash tuns...

Heat goes up. The lids on these things are hollow. That's where the heat is getting out. Get a can of that spray insulation from Home Depot or Lowe's and spray the lid full.

The other thing I've found with mine is that the lid seals well until steam pressure builds up inside the cooler and it creeps up and loses the seal. I put a few pound weight on the lid during the mash.

These two things brought my losses down to within 1 degree. I can live with that. I will try the foil trick though!

 

[chigundo]

I just shoe-horned a Bayou Classic kettle into a round cooler.*

Last few batches I did I may have lost from .5F-1.0F in a 60 min mash.


* idea from member Ben the Brewman



EDIT: I really don't understand how these cooler manufacturers aren't considering this idea of going with a stainless liner. If I thought I could buy a 15 gallon cooler, round or rectangular, with a stainless liner, I'd buy right now.

Your way is cheaper, but still: https://www.kickstarter.com/projects/958078058/chapman-homebrew-equipment-mash-tuns-fermenters-ke

 

[chigundo]

Oops, double post.

 

[dfhar]

I just step mash all of my beers and use separate beta and alpha rests. If I'm doing a beta rest at 145, it doesn't really matter if I end up at 147. If I'm doing an alpha rest at 160, it doesn't matter much if it ends up being 158 or 162. To control fermentability, I mash for a longer or shorter time at the beta temperature. I find time easier to control than temperature.

 

[Ski12568]

1. i heat my strike water to around 175-180 then pour it in my mash tun and close the lid. I let it sit for a while to preheat.
2. Then i open the lid and stir the water around until it settles at a degree or two above what beersmith tells me my mash in temp is.
3. mash in and stir until I am at my mash temp
4. Then i put a piece of aluminum foil on the grain bed. Close the lid and cover with a blanket.

My cooler is a typical run of the mill cooler that I bought off craigslist for 15 bucks. The lid is hollow and not insulated, in fact it has a little door built in to the lid that you can use to reach in and grab a brew.

I don't even lose a degree over a 60 minute mash this way.

I did this in Friday and it worked great!


Beginning temp
View attachment ImageUploadedByHome Brew1428950528.275669.jpg

Foil on
View attachment ImageUploadedByHome Brew1428950771.873645.jpg

After 60 minutes, this was the lowest after checking multiple spots
View attachment ImageUploadedByHome Brew1428950713.794897.jpg

Thanks for the tip. I even forgot to cover with a blanket.

 

[GreenSpyder]

This is a great thread on a good topic, and has helped me immensely, since moving out of the kitchen into the garage. Things I've taken away from this thread, that definitely made a difference are the following:

I fold a blanket and wrap it around my 10 Gallon Igloo MT, and secure it with bungee cords, tucking a large section over the top and into the sides.

I think smaller quantities of water heat faster, so I get 3 gallons to 180 and use this to preheat the MT.

I heat another 4 gallons while the MT heats, then empty the MT back into the kettle and heat to about 168. This is where I mash.

I cut a 2" thick false top out of a disposable styro cooler lid, and float this on top of my mash (thanks opiate82).

My first time out I had trouble maintaining over 142F. Now (in a 52F garage) I have to stir my temps down, and lose about 1F/hr.

Thanks to all for this advise.

 

[beernutz]

I use an Igloo cube cooler and to be quite honest I have used many of the tricks outlined in this thread such as preheating the tun, putting aluminum foil over the mash, covering the outside of the cooler with an insulating material and when doing those I almost always stay right on my target temp for the entire mash. However, truth be told I generally gain^H^H^H^H lose only 2 degrees over the course of a 60 minute mash by doing absolutely nothing extra.

My palate is not refined enough to tell the difference between a beer mashed at exactly 149 versus one that started at 149 and ended up at 151^H^H^H 147 over the course of an hour so I just don't worry about doing those extra procedures at all. If I remember to, then breaking out the aluminum foil is pretty easy so I'll do that one but if I forget, its no big deal. YMMV.

 

[beergolf]

However, truth be told I generally gain only 2 degrees over the course of a 60 minute mash by doing absolutely nothing extra.

I hope you mean lose 2 degrees. If you are saying you gain 2 degrees you must have flunked your science class. It is impossible to gain temp without some source of energy. If you are gaining temp without energy you should call the government because you have just found a new source of energy. Maybe you can cure global warming.

You just are not stirring enough before you take your temp. Then when the temp stabilizes that is the true temp.

 

[grrickar]

I preheat my Igloo 10 with hot water, then shoot for a few degrees over figuring I can stir and cool down, but heating back up isn't an option unless I add boiling water - which i do sometimes from an electric tea kettle.

I was losing a lot of heat from the lid so I drilled it and shot it full of expanding foam. It holds much more constant now. Having the mash tun in the warm house as opposed to the cold garage helps too, and if nothing else I can wrap some reflectix around it.

 

[Genuine]

For the past year I've been using a Mini E-HERMS system to keep my mash right at temp. It's a combination of a mini HERMS coil. a temp controller, cooler and pump. I couldn't be more happy with my current set up for the simple reason that it didn't cost me a fortune to keep my mash at the right temp. I've noticed a great improvement of my beers and the repeatability has increased as well. I got the idea from the $50 Herms thread that's on this site. Helped me greatly!

 

[Natdavis777]

My old rectangle cooler was a champ. I would pre-heat with hot water, let it sit for 15 min or so, and then dough in at the appropriate temp. Never lost more than 2 degrees. Never covered with blankets or anything. Just kept it inside the house in the winter, and didnt have to do much in the summer. My buddy uses it now, and has the same experience.

 

[beernutz]

I hope you mean lose 2 degrees. If you are saying you gain 2 degrees you must have flunked your science class. It is impossible to gain temp without some source of energy. If you are gaining temp without energy you should call the government because you have just found a new source of energy. Maybe you can cure global warming.

You just are not stirring enough before you take your temp. Then when the temp stabilizes that is the true temp.

Yes, I meant I lose 2 degrees.