17 replies to this topic

[DaBearSox]

So I use an igloo round cooler as my tun and I have been noticing that my final gravities have been finishing a little on the low side. I figured it has to be a problem with my mash temps and I went out and bought a traceable thermometer. I made up a batch of ESB last night and noticed some interesting readings with this new thermo. This thing has got about a foot long probe (thats what she said) so i can get it down through most of the mash. Brought my water up to temp, dumped it in the cooler than dumped the grain on the top. Stirred the hell out of it to break up all the clumps and get it even, put the top on let it sit for about 7 minutes for the temp to regulate....here is where i ran into my first problem.I took readings at about 4 different places in the mash Middle was 151-152 other areas were around 153 (where i wanted it) and i think 1 or 2 were around 150. So i said oh well I don't know how i am supposed to fix that so i just put the top on and let it go for about an hour. Take the top off after the hour to check temps again. Stuck it in a few different places and i got temps ranging from 142-150...mostly around the 146-148 range so it looks like I am losing a lot more heat than i want to and this must be the reason my beers are drying out. The thermo I used to use had a lot shorter probe and when I was using that it seemed like if I lost any heat it would be maybe one degree and not anything that big of deal. Now it seems this new one is more sensitive and is giving me more accurate readings. What can I do to help me with these problems? I really have no clue about the disparity in the initial readings....i thought the temp should just even out after a little time but according to last night that doesn't happen. Also is there just dead airspace in those coolers....I know the top has some so I am thinking of pumping some of that liquid foam stuff in there but was also wondering if there is space i could pump some into the sides or is that already filled with some sort of insulate. Any other ideas? Thanks

[Greatfookin]

Wrap that sucker in an old sleeping bag.

[BrewerGeorge]

I wrapped mine in aluminized bubble wrap. It's available from Lowes in the heating section, probably Home Depot as well.

[DaBearSox]

alright those are good ideas but any ideas on why i am not getting different readings at different spots in the tun? I would think after stirring enough and giving it a few minutes to even out i wouldnt get that problem...

[Sidney Porter]

what formula are you using to calculate strike temp? It may not be adjusting for you thermal mash of you tun. A cooler should only lose a 1 or 2 degrees over an hour. I wonder if you are not really stabalized at the 151-153.When I used a cooler I would bring it in the house the nite before brewing so that it was always the same temp evey morning when I brewed, I would also messure the temp of the grains right before calculating the strike temp. also if your volume mesurements are off with you strike water that could impact the calculation significatly.Some people also preheat their tun to take the termal mass out of the equation.I mash in a keg so I know the thermanl mass is 0. It takes about 5 minutes to stabilize. I put a blanket over the tun. I only lose 2 degrees over an hour.

[DaBearSox]

I am using Promash to calculate my strike temp...and you know what I am not sure if i have been calculating for thermal mass...i dont think there is an option on there. So that may be what brings me down a little. Even then though why would i be getting different readings in 4 different places? I let it sit for 7 minutes before I took my readings so it could stabilize, and at that point i got readings of 150-153.The cooler is always in the apartment b/c its got no where else to go, and I also measure the grain temp right before I add it to the tun. My measurements for the water are with a nalgene bottle so it could be slightly off at the 32 oz mark but i can't imagine by much. My grain measurement is from the digital scale at the LHBS.

[Sidney Porter]

there is a process in the FAQ to test thermal mass for promash. The default in pro mash .3. When i used a cooler I was at .1 (but I use strange brew which may not have the same calc)

[Sidney Porter]

I let it sit for 7 minutes before I took my readings so it could stabilize, and at that point i got readings of 150-153.

I don't know if 7 minutes is enough for a cooler. It seems to take about 5 minutes for my keg and I am getting 0 obsorbion into the tun.

[MakeMeHoppy]

I always cover my cooler with a couple big towels for a blanket. You can feel how warm it is against the cooler top, so I know without them I'd be losing heat. On your dough in technique, ever try putting some water in first and then some grain to make it easier to mix and not have dough balls?

[DaBearSox]

On your dough in technique, ever try putting some water in first and then some grain to make it easier to mix and not have dough balls?

That is what i do...i guess i should do it in smaller increments though...

[CaptRon]

What I do with my Rubbermaid round coolers, is while I am heating up my strike water I put hot tap water in it to kind of pre-heat it. I don't lose much heat from my tun actually. I am actually surprised at how cool the outside of the cooler is - you would never know that it is full of ~150 degree stuff..

[ColdAssHonky]

While I'm heating my strike water, I set my rectangular cooler upside down on top the kettle. The rising steam gets the material heated up in no time.

[CaptRon]

While I'm heating my strike water, I set my rectangular cooler upside down on top the kettle. The rising steam gets the material heated up in no time.

But my false bottom and mash pad would fall out.

[ColdAssHonky]

But my false bottom and mash pad would fall out.

I might take a little longer, but you might be able to get the same effects right side up.

[davelew]

I have a 10 gallon Rubbermaid cooler (aka the Gott cooler). I drilled six holes in the top, filled them with "great stuff" foam, and plugged each hole with a nylon screw. I also sprayed some great stuff around the spigot, because the insulation seemed a little thin there.Last saturday, I brewed an imperial stout with 17 pounds of grain at 149, then mashed out to get to 170. Then I batch sparged, brought the wort to a boil, boiled for an hour, chilled, drained, pitched the yeast, and aerated.After all that, the temp was still about 168, so I would guess that I lost 1 degree F per hour over two hours. Since the grainbed was still so warm, I heated up some sparge water, and re-sparged the grain to make 3 gallons of a dry stout.

Also is there just dead airspace in those coolers....I know the top has some so I am thinking of pumping some of that liquid foam stuff in there but was also wondering if there is space i could pump some into the sides or is that already filled with some sort of insulate. Any other ideas? Thanks

[3rd party JKor]

I measure out my mash water at several degrees above my intended strike temp. For example, if my strike temp is 167, I fill my cooler with the correct amount of water at 175. I let it sit for 10-20 minutes to heat up the tun, then if the water is still too hot I just open the cooler and stir it around until the temp is exactly where I want it, then I add the grain.

[DaBearSox]

I measure out my mash water at several degrees above my intended strike temp. For example, if my strike temp is 167, I fill my cooler with the correct amount of water at 175. I let it sit for 10-20 minutes to heat up the tun, then if the water is still too hot I just open the cooler and stir it around until the temp is exactly where I want it, then I add the grain.

that is a great idea, i'll have to do that on my weekend brews when time isn't an issue

[3rd party JKor]

that is a great idea, i'll have to do that on my weekend brews when time isn't an issue

It's worked out pretty well. Before I blew up my RIMS, I used to just add my strike water to the MLT cold, and let the RIMS heater get it to temp. I could go do other things while it was warming up and it gave the added benefit of getting the MLT up to temp as well.