3rd AG Brew/Coleman xtreme mashtun problems

I did my 3rd AG brew this past weekend and continue to have problems with strike temp and temp drops. This is driving me absolutely nuts! I preheated my tun once with about 2 or 3 gallons of 175 deg water and within 15 min the temp dropped to below 150. I tried it again with 180 deg water and even though it was preheated it still dropped to low 160s. Finally I put about about 7 gallons of 200 deg water in let it sit for 30 min. When it reached my strike temp ~165 deg, I added my grain and stirred. It stayed at 150 pretty much for an hour.

I had 10 lbs of grain.
Beersmith said 165 strike temp after adj for equipment
I have a 70 qt Coleman Xtreme cooler w/ SS braid

What the heck am I doing wrong/not doing? I have heard great things about the cooler!

I don't think you're doing anything wrong. You might try adjusting your dough-in temp a couple degrees if you wanted to hit 152 but that sounds about right. Other than that I don't see that you're doing anything wrong.

Should I really have to preheat it 3 times? Each time I drained the water and reheated it. Granted heat does escape whenever I open the lid to check temp.

was the 7 gallons @ 200 just to preheat the tun?

EonBlue66 said:

was the 7 gallons @ 200 just to preheat the tun?

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lol yes. That was the third time heating the cooler up too. Then i put 12.5 qts of 175 deg water in there and let it drop to strike temp before dough in.

Have you checked the temperature of your grains. Beersmith has the Strike/Infusion Temp Tool. You can make adjustments to your strike water temp based on the temperature of your grain. Maybe your grain is cooler then normal. This will allow you to make adjustments.

When I do my mash in, I add the strike water, then add my grains right away. If you check off adjust for equipment, beersmith adds the extra degrees knowing your going to lose some heat to heating the cooler. So you don't need to wait for the temp to drop to a normal strike temperature without equipment adjustment. Is that what you are doing, or are you waiting to add grains?

I brew in my garage, and if it's a cooler day, I may add a few degrees to what should be my strike temperature.

Your mash temps should be between 150 degrees to 156 degrees on average.

Is your equipment setup right in Beersmith?

I have the exact same setup as you and I usually add most of my strike water at around 180 and close the lid. I will finish getting everything setup, crush my grain, refill my HLT, and then check temp. The MLT will usually be around 160-165 after around 20-30 mins. Then I add the rest of my strike water and wait until it's all at the strike temp I need based off my grain bill, usually 10-12 degrees over my mash temp, and then dough in. Slowly dump in grain while stirring constantly and once all the grain is in I'm usually within 1-2 degrees of my mash temp. I let the grain settle for about 10 mins, stir it again and then let it sit until it's converted. The most temp loss I've had over an hour is about 1.4 degrees and that was outside in the wind with the temps in the lower 40's. Last batch I hit my mash temp at 155.2 and finished 60mins later at 154.5.

I think you may be looking at this wrong, just add some hot water to your tun I use about a gallon and let the cooler warm up. Empty the cooler and add your strike water around 12-14 degrees over your strike temp then dough in. After you dough in measure the temp it should be right around where you need it to be.

Oh, I didn't realize this was all at the same time. I thought these were all different attempts for some reason and the 200 deg attempt was your last attempt. No that doesn't sound quite right though my experience is with the 10 gal water coolers which only lose 1-2 degrees per hour with the lid on.

Myke_J said:

Last batch I hit my mash temp at 151.2 and finished 60mins later at 154.5.

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That's interesting because it seems you managed to violate some basic laws of thermodynamics.

mightynintendo said:

Oh, I didn't realize this was all at the same time. I thought these were all different attempts for some reason and the 200 deg attempt was your last attempt. No that doesn't sound quite right though my experience is with the 10 gal water coolers which only lose 1-2 degrees per hour with the lid on.

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Oh it was different attempts Thats what makes it so strange for me. I just never though I would have to heat, drain, heat, drain, then finally add water and let drop to strike temp. Seems like I spent WAY too much time getting that thing to a temp where it wouldnt drop beyond my strike temp

I don't understand why you're trying to pre-heat your cooler. Just let the software figure it out for you. OR if you don't want to do that, just add your strike water 10-15 degrees higher than your strike temperature. Shut the lid, wait 10 mins to allow the cooler to absorb the heat. Check the temp. If you are too high, add a few ice cubes and/or leave the lid open.

70 qt is a massive cooler. 2 gallons of water isn't enough thermal mass to do much.

Duster72 said:

I don't understand why you're trying to pre-heat your cooler. Just let the software figure it out for you. OR if you don't want to do that, just add your strike water 10-15 degrees higher than your strike temperature. Shut the lid, wait 10 mins to allow the cooler to absorb the heat. Check the temp. If you are too high, add a few ice cubes and/or leave the lid open.

70 qt is a massive cooler. 2 gallons of water isn't enough thermal mass to do much.

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Still learning Beersmith and AG brewing. Beersmith set to 17.5 gallons volume, 10 lb weight, Material is plastic. With adjust for equip checked it gives me 164 deg Strike Temp to get to 150 deg mash. Now do I should I just add that water and just immediately add grains and stir? Last time I tried adding grains first and then adding around the same temp and I had to add A LOT of hot water to bring it up to mash temp.

Bamfordjf said:

Still learning Beersmith and With adjust for equip checked it gives me 164 deg Strike Temp to get to 150 deg mash. Now do I should I just add that water and just immediately add grains and stir?

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Yes and no. I use a Igloo 10 gal which is well dialed-in in Beersmith. BUT if it's cold outside, etc, Beersmith tends to run 1-3 degrees too cold in my experience.

What I would do is this:

1) See what Beersmith says your strike temp should be WITHOUT adjust for temperature. This tells you what the strike temp should be for the water + grains. This is important.

2) See what Beersmith says your strike temp should be WITH adjust for temperature. This gives you an idea of what it thinks your strike temp SHOULD be.

Now, I take temp #2 as a starting point. Let's call it 170. I would heat my water up to 173ish, add it to the cooler, shut the lid and give it some time (as long as it takes me to mill my grain and weigh my chemicals). Now I take my temp in the cooler and compare it to what beersmith gave me in #1. Let's call it 160. I always err on the side of warm, because it's a lot easier to lower the temp via ice cubes than it is to raise the temp via boiling water IMO.

So, if you water is around 162ish, you should be golden, just add your grains and stir. If it's too hot, add a couple ice cubes. That should get you to your target (150ish) once you dough in. If you are 1-2 higher than your target (since Beersmith said 160 and you went ahead and doughed in at 162), you can add a handful of ice cubes and move on with your life.

Now you can look back and compare what temp you started with (173 in this example) and compare it to Beersmith's value #2 (adjust for temp) to see how it worked and compensate in the future. After a few times I learned that I needed to shoot 3-4 degrees higher than BS's suggestion. Of course, ambient temps are always going to change, so I always went ahead and did all those calcs every time to be sure. I always went 3-5 degrees too warm and then used a few ice cubes to lower the temp as necessary.

Also, remember that your cooler is going to lose some heat over the course of the mash, so you might want to shoot for a initial temp 1-2 degrees over your target so your 150 mash doesn't end up at 146 at the 45 minute mark.

I hope that helps. Lots faster to explain this verbally than writing it out.

And this is a good argument for why I build a HERMS system - you just can't get a consistent, easily repeatable beer this way. But you can still make great beer!

mightynintendo said:

That's interesting because it seems you managed to violate some basic laws of thermodynamics.

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I'm magic

Meant 155.2

One thing that could mess things up is if you get liquid leaking into the insulation of the cooler. Once the insulation gets soaked, it will really lower the insulation value. You might want to ensure this is not the case.

I might be wrong but I think these coolers also have a vacuum inside the insulation. If your cooler has a crack or was poorly made or if you damaged it when converting it to a mash tun, you could have leaked air into that vacuum which will have a huge impact on your heat retention. When you put hot water in, does the outside of the cooler get pretty warm? If so then you're losing more heat than you should be. The outside of the cooler should be only slightly warm if at all even after an hour of mashing.

There's no way these things are vacuum sealed vessels. Not for the price coolers sell at.

I have the same cooler. I heat up my strike temp per Beersmith, then add 14-15*F. So, if strike is 164, I heat to about 179-180. Put in ALL of the strike water. If it says dough in with 3.5 gallons, add 3.5 gallons of 180*F. Let it sit closed for 10 or 15 minutes. This will cause you to lose maybe 8-10* or so. Open it up and stir until the water cools down to your real strike temp (164*)--this should only take a few minutes--then toss in the grains.

CAVEAT: If you store the cooler in a really cold place (garage, outside, whatever) 15* might not be enough to get the cooler to reach equilibrium... Maybe try 20-25* instead. It's all about dialing in for your setup.

Doing it this way means that you are only heating up the amount of measured water needed ONCE. No need to drain it out and add in new water again so long as the MLT is reasonably clean. I also use a wooden dowel "dipstick" measured for my MLT to make sure that I've transferred the right amount of H20.

Munsoned said:

I have the same cooler. I heat up my strike temp per Beersmith, then add 14-15*F. So, if strike is 164, I heat to about 179-180. Put in ALL of the strike water. If it says dough in with 3.5 gallons, add 3.5 gallons of 180*F. Let it sit closed for 10 or 15 minutes. This will cause you to lose maybe 8-10* or so. Open it up and stir until the water cools down to your real strike temp (164*)--this should only take a few minutes--then toss in the grains.

CAVEAT: If you store the cooler in a really cold place (garage, outside, whatever) 15* might not be enough to get the cooler to reach equilibrium... Maybe try 20-25* instead. It's all about dialing in for your setup.

Doing it this way means that you are only heating up the amount of measured water needed ONCE. No need to drain it out and add in new water again so long as the MLT is reasonably clean. I also use a wooden dowel "dipstick" measured for my MLT to make sure that I've transferred the right amount of H20.

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Thanks for the suggestion! I believe I am going to try doing that next time. Don't really have time to fuss with preheating the cooler. Will report.

No problem. It can take a few attempts to dial it in, but when you get it, it's much better than heating, filling, heating, draining, heating, refilling, draining again, topping up, remeasuring the amount of water again....

I was taught to add a gallon of really hot water to preheat, but I soon figured out that doing it that way required heating water twice, and measuring the amount of water twice--I'm a "pragmatic" brewer!

Good luck!