Losing a ton of heat during mash in

I have an orange igloo cooler (10g) for a MT. The same for a HLT, but with a 1500W element inside. The HLT is new and i've done two batches so far with it with poor results.

At first I was using a 5g pot to dump in my mash/sparge water all at once. Now that I have the HLT I drain with a hose/ball valve into my MT. These last two times I lost almost 30F in the mash-in. The first time I didn't pre-heat (I never did before, just raised my strike water temps instead). So I pre-heated with 150F water for 20 minutes this time. Grain temps are around 64.

This batch was 8g, 19lbs 2-row and 0.57lbs aromatic. I calculated 6.5g @ 175 to mash in. I did this and hit 147, I needed 155-154. It sat at 147 for 20 until I got a few gallons drawn off and heated, then went up to 164 for another ten when I put it back in. What a pita, this hasn't happened to me since I first started.

My process: open ball valve, drain 6.5 g, stir like hell for a few minutes, close and tie down lid. I usually lose 1-2 degrees an hour. My guess is that draining then stirring is taking to long and the water is rapidly cooling. However I have seen other people take their sweet time while doughing in and no problems. I hit a poor 70% for efficiency (usually in the low 80's), who knows how it will ferment. So what gives? What is everyone else's experience with doughing in and what temps do you use?

I generally allow the strike water to begin to boil, then allow it to cool off to the temp I strike at. Seems like when it is cooling it retains more heat than water that has just risen to the strike temp and was poured in. Preheat is also almost mandatory to insure the temp drop isn't excessive. I also allow my grains to reach ambient temp before I use them, straight out of the fridge tends to use too much of the reserve heat to bring their temp up to strike. Just sayin...
Wheelchair Bob

If I add water over 180 degrees in my cooler, it warps and cracks. So I add 180 degree water, and let it cool down to my strike temp (generally about 166 or so).

It cools FAST at first, then once it settles, I only lose about 1-2 degrees an hour in the mash.

I drain through a 1/2" valve in my hlt into my mash tun which is one of the cheap blue 12gal igloo cube things from big lots. I calc my strike temps figuring for a 4-5 degree loss without preheating the tun. Then I purposely overshoot my temp by a few degrees and cool the mash down those few degrees with room temp water. I've never had an issue. You're always better to overshoot and compensate than having to heat more water.

Spintab said:

I drain through a 1/2" valve in my hlt into my mash tun which is one of the cheap blue 12gal igloo cube things from big lots. I calc my strike temps figuring for a 4-5 degree loss without preheating the tun. Then I purposely overshoot my temp by a few degrees and cool the mash down those few degrees with room temp water. I've never had an issue. You're always better to overshoot and compensate than having to heat more water.

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Before I upgraded there was no need to over shoot. But even today I did try to get warmer than needed and still failed.

Yooper said:

If I add water over 180 degrees in my cooler, it warps and cracks. So I add 180 degree water, and let it cool down to my strike temp (generally about 166 or so).

It cools FAST at first, then once it settles, I only lose about 1-2 degrees an hour in the mash.

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Thanks Yooper, i'll give this a shot next batch. The cooler seems to be good even over 200 (left it on for longer than planned). I hope this is the answer to my problems

Rbeckett said:

I generally allow the strike water to begin to boil, then allow it to cool off to the temp I strike at. Seems like when it is cooling it retains more heat than water that has just risen to the strike temp and was poured in. Preheat is also almost mandatory to insure the temp drop isn't excessive. I also allow my grains to reach ambient temp before I use them, straight out of the fridge tends to use too much of the reserve heat to bring their temp up to strike. Just sayin...
Wheelchair Bob

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I didn't know people stick grains in the fridge

Mojzis said:

I didn't know people stick grains in the fridge

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I don't think many people do. I don't see it being important, like hops or especially yeast. As long as your grain stays dry, you're good.

I buy my grains within a couple of days if brewing. My LHBS has excellent grain mills. Never had a problem with the crush. I also keep my grains at room temp.

I didn't notice if anyone mentioned it, but do you preheat your mash tun? I dump in a gallon or so of hot tap water, splash it around and seal it up and leave it while I'm heating strike water and such. Then dump it out when I'm getting ready to mash in. beersmith factors in for whether or not you take this step.

I've been preheating my cooler and overheating the strike-water but having the same problem. Pretty sure I am losing temp in the cold weather as it transfers from the HLT to the MLT. Still working on figuring out the adjustment, got closer this morning.

govner1 said:

I buy my grains within a couple of days if brewing. My LHBS has excellent grain mills. Never had a problem with the crush. I also keep my grains at room temp.

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I keep 100lbs of 2-row in zip lock bags in a plastic tub that sits in the corner of my kitchen. Grinding my own I usually get low 80's for efficiency.

Revvy said:

I didn't notice if anyone mentioned it, but do you preheat your mash tun? I dump in a gallon or so of hot tap water, splash it around and seal it up and leave it while I'm heating strike water and such. Then dump it out when I'm getting ready to mash in. beersmith factors in for whether or not you take this step.

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Yeah I put that up that I did pre-heat ( 20 min with 150F) and still lost 30F. And I don't bother using beersmith anymore for calculating the mash. Always off for me.

geckholm said:

I've been preheating my cooler and overheating the strike-water but having the same problem. Pretty sure I am losing temp in the cold weather as it transfers from the HLT to the MLT. Still working on figuring out the adjustment, got closer this morning.

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Yeah its a pain. I'm going to give what Yooper suggested a shot. Heat to 180 or higher, transfer to MT and let it sit until it hits striking temp then dough in.

Considering I BIAB and don't use a cooler, my method may not work for you.

One thing you can try is if you choose to keep your grains in the fridge, place them somewhere warm for a bit before you mash in to help raise the ambient temp. I put them in the sun on black concrete in a clear plastic bag. Another option is to get a black 5gal pail and leave that in the sun.

Now mind you my ambient temp grains are 74F and I just leave them in the sun and they can hit 80F. This reduces the change in temp slightly. Just make sure you use a thermometer in your grains before you mash in and do some quick math!

I ALWAYS pre heat my mash tun with 140 degree water. I always hit my number dead on, and don't even drop a degree with my 10 gal round home depot cooler.

In beersmith mash profile, set your grain and mash tun temperature. This time of year I have it set for basement temp of 67°. Beersmith calculates strike temp. For my last batch I had a strike temp of 163° to mash at 148°. I use my strike water to preheat my cooler so I add 10-11° to the temp. I heat my water to 174° and fill the cooler with that water. I wait 10 minutes and the water temp drops to the 163° beersmith recommended. I add the grain and stir and the temp is now at 148° and will hold at that temp. In the winter I use an electric blanket on the top of the cooler to keep the heat loss down.

Those seem like wild swings in temp, thermometer maybe? I guess that wouldn't account for the loss in effeciency, or would it?

Hawaiibboy said:

Considering I BIAB and don't use a cooler, my method may not work for you.

One thing you can try is if you choose to keep your grains in the fridge, place them somewhere warm for a bit before you mash in to help raise the ambient temp. I put them in the sun on black concrete in a clear plastic bag. Another option is to get a black 5gal pail and leave that in the sun.

Now mind you my ambient temp grains are 74F and I just leave them in the sun and they can hit 80F. This reduces the change in temp slightly. Just make sure you use a thermometer in your grains before you mash in and do some quick math!

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Lol no where did I say I use a fridge for my grains. I stated they are ambient at 64F. Who keeps grains in the fridge? Btw not much sun in NY during winter!

Ondori said:

I ALWAYS pre heat my mash tun with 140 degree water. I always hit my number dead on, and don't even drop a degree with my 10 gal round home depot cooler.

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Sweet, thanks. Rub it in!

iaefebs said:

In beersmith mash profile, set your grain and mash tun temperature. This time of year I have it set for basement temp of 67°. Beersmith calculates strike temp. For my last batch I had a strike temp of 163° to mash at 148°. I use my strike water to preheat my cooler so I add 10-11° to the temp. I heat my water to 174° and fill the cooler with that water. I wait 10 minutes and the water temp drops to the 163° beersmith recommended. I add the grain and stir and the temp is now at 148° and will hold at that temp. In the winter I use an electric blanket on the top of the cooler to keep the heat loss down.

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Right. I think what i'm doing wrong is adding water to my grains not the other way around (and at the same time pre heating the MT). This is along the lines of what Yooper suggested and what i'll try next.

doby said:

Those seem like wild swings in temp, thermometer maybe? I guess that wouldn't account for the loss in effeciency, or would it?

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Thermometer is fine, perfectly calibrated with my other 3. I think the efficiency is from the temp troubles and increased grain amount in my 10g cooler.

Mojzis said:

Lol no where did I say I use a fridge for my grains. I stated they are ambient at 64F. Who keeps grains in the fridge? Btw not much sun in NY during winter!

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I have to keep them in the fridge otherwise my grains get moist from ambient moisture in the air. Yeah here in Hawaii it can be cloudy but normally it's somewhat sunny.

I forget that i am blessed with vastly different weather.

Why not zip-lock baggy them? I keep 100 pounds ziplocked and in plastic storage bins to keep mice out.

Mojzis said:

Why not zip-lock baggy them? I keep 100 pounds ziplocked and in plastic storage bins to keep mice out.

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That's a great idea! Thanks! I don't have that much grains but I think I will be doing that once I start to purchase in bulk and get my own mill.

Currently I buy by the batch but I am starting to see how the price can add up quick.

The first time I used my 10 gal round cooler tun, I guessed at the temp loss, was close, and it ended up being 14 degrees F loss. Now, I just heat my strike water 14 degrees above my mash temp, pour it in, and stir in my grain. I'll compensate a bit when brewing outdoors in the winter.

One of the things I do is to bring to a boil 3 qts of water from my future sparge water. I have this ready at the start of mash. It's just to be used if I am low at mash temp. I do this in a separate pot on my stove. As an example with my last recipe with 32# of grain and 10.5 gallon of water if my mash was 3° low I need to add 2.5 quarts of 205° water if 2° low I needed 1.75qts, and if 1° I add less than a qt. If I hit my number I just pour the remaining water into my sparge water/ HLT. I make 11 gallon batches, so you can cut the amount by half if you do 5 gallon.

What where the ambient temps when you first started and didn't have these problems? Middle of the summer? You have to realize how much heat an ice cold cooler and parts will take away. There's also a huge difference in the temp of the grain from summer to winter.

Revvy said:

I didn't notice if anyone mentioned it, but do you preheat your mash tun? I dump in a gallon or so of hot tap water, splash it around and seal it up and leave it while I'm heating strike water and such. Then dump it out when I'm getting ready to mash in. beersmith factors in for whether or not you take this step.

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That's what I do. 1 pot on the stove as a preheat then dump before sparge water.

mattfmoore said:

The first time I used my 10 gal round cooler tun, I guessed at the temp loss, was close, and it ended up being 14 degrees F loss. Now, I just heat my strike water 14 degrees above my mash temp, pour it in, and stir in my grain. I'll compensate a bit when brewing outdoors in the winter.

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That's exactly what I do, never off more than a degree, I never understood the preheating mash tun thing. It's just one extra step that's not really needed.

One reason why preheating the tun yields unpredictable results is that the upper area of the cooler is often ignored though when the tun is full of mash, those areas come into contact and steal heat. If you go in with the full strike water volume, overheated a good 10F and tilt the cooler about so that all surfaces can take the heat, you'll end up way more stable by the time you add the grain.

iaefebs said:

One of the things I do is to bring to a boil 3 qts of water from my future sparge water. I have this ready at the start of mash. It's just to be used if I am low at mash temp. I do this in a separate pot on my stove. As an example with my last recipe with 32# of grain and 10.5 gallon of water if my mash was 3° low I need to add 2.5 quarts of 205° water if 2° low I needed 1.75qts, and if 1° I add less than a qt. If I hit my number I just pour the remaining water into my sparge water/ HLT. I make 11 gallon batches, so you can cut the amount by half if you do 5 gallon.

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I'll keep this in mind for the next batch in case it doesn't work out. Thanks

Bobby_M said:

What where the ambient temps when you first started and didn't have these problems? Middle of the summer? You have to realize how much heat an ice cold cooler and parts will take away. There's also a huge difference in the temp of the grain from summer to winter.

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I brew indoors through the winter and this has started in the last month (since I got my new equipment and changed up my process). So no ambient temp changes. I keep my apartment between 62-65.

bandt9299 said:

That's exactly what I do, never off more than a degree, I never understood the preheating mash tun thing. It's just one extra step that's not really needed.

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Yeah, the pre-heating doesn't interest me, especially since I'm way more concerned about having a sticky, low-attenuating mash, than a highly fermentable mash that will give me dry, drinkable end product.

I did a test with my mash tun today using only water to see how well it would retain heat. I had heating issues using it for my first all grain batch. Temps dropped too low.

I did a test with a little over 3 gallons. My "strike" temp was 170F. I did not preheat the Lowes circular style cooler.

I closed the lid when it was 165F. In one hour the temp went from 165F down to 153F. Again using only water. Clearly not good.

Now the most obvious question is, does the lack of grain in the cooler speed the drop in temp? I assume the grain itself would help act as insulation and help retain that heat. But by how much?

If not, not sure what else I can do. I did not cover it with a blanket. That might help a couple degrees. The outside weather here today is fine, 68F. I've read people have tried to insulate the lid with spray foam insulation. Maybe I can try that.

The temperature drop you saw was mostly from the cooler absorbing the heat of the water. When you add grain the temperature will drop even more since you are warming up the grain. You have to account for it. You have to preheat the cooler. Read through the thread again. My strike water at this time of year for me is about 25° higher than mash temp.

Revvy said:

I didn't notice if anyone mentioned it, but do you preheat your mash tun? I dump in a gallon or so of hot tap water, splash it around and seal it up and leave it while I'm heating strike water and such. Then dump it out when I'm getting ready to mash in. beersmith factors in for whether or not you take this step.

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+1 to this. I do it too - makes a huge difference.

I also took to draping a flannel-lined shirt over my mash tun and it cut my heat loss down to 1 degree an hour.

What is the difference if I pre heat my mash tun and heat my strike water to 166 or skip the pre heat and heat my strike water to 173. I usually lose only 1-3 degrees so I'm still wondering why this preheat step is necessary. No huge difference here. For me anyways.

bandt9299 said:

What is the difference if I pre heat my mash tun and heat my strike water to 166 or skip the pre heat and heat my strike water to 173. I usually lose only 1-3 degrees so I'm still wondering why this preheat step is necessary. No huge difference here.

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I think we are talking about the two different methods of pre heating the cooler. Some like to dump a gallon or so of heated water in the cooler and then dump it out and add the strike water. I agree that it is unnecessary. I heat my strike water to the temperature that accounts for all the temperature losses. You lose temperature any time you have to warm something up. Be it grains or your cooler. Whether you realize it or not that is what you are doing. You are not skipping the pre heat, you are accounting for the loss with the higher temperature strike water.

I preheat with my strike water. I usually add it to the mashtun at around 185* and wait 30 minutes. The temp drop is between 14* and 17*. I'm still working out my temperature kinks but this is definitely a very important step for my set up.

I just like to brew and teach the simplest way, in my opinion anyways. If you can simplify your brew day start to finish you can save time and energy.. I have brewed many times on the local brewpub 7 BBL brewhouse and we never preheated the tun. It was hot water mixed with room temp grain and you live and learn. There is no one perfect method that works right for everyone. But to me it's the method that is the easiest to teach and learn.

Whether you know it or not the 7bbl local is taking into account the grain absorption temp. This stuff is not alchemy. It is science. I'm sure someone can come on here and explain the heat loss in joules, but the main idea here is to help the homebrewer. The confusion here is the term pre heat. You have to account for all energy loss by grain absorption and mash tun loss. No if, ands, or buts.

So I know my previous statements might not have helped but this might:

I was watching the equipment setup video for BeerSmith 2.x and it seems that based upon the mash tun construction material you'll have different temp losses to the MT itself. In addition to this loss your biggest factor is time, I'm not sure if BeerSmith takes into account air temp that you are brewing in. This can cause big losses in temp over time, as some of you have described.

My suggestion would be to grab a free trial version of BeerSmith or another full featured program in and plug some numbers in to see what your potential losses are/could be.

I personally use iBrewMaster on my phone and have been able to get decent results for my BIAB temps. I am also brewing in 68-78F weather and using a s/s kettle to mash and boil in.

I have beersmith and have added the specific heat of the tun to the calculations. From everyone's comments i'm sure its from not pre-heating with my strike water. By doing that i'll get the tun all the way heated and have less time the water comes into contact with the relatively cool air.

Mojzis said:

I have beersmith and have added the specific heat of the tun to the calculations. From everyone's comments i'm sure its from not pre-heating with my strike water. By doing that i'll get the tun all the way heated and have less time the water comes into contact with the relatively cool air.

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I personally like the heat all your strike water to about 10-20 degrees higher then calculated and then just wait for it to drop to your calculated strike temp based upon the grain quantity and grain temp. That was how I used to pre-heat my cooler in OR throughout the year and it seemed to work well.

Good luck!

Rami said:

I did a test with my mash tun today using only water to see how well it would retain heat. I had heating issues using it for my first all grain batch. Temps dropped too low.

I did a test with a little over 3 gallons. My "strike" temp was 170F. I did not preheat the Lowes circular style cooler.

I closed the lid when it was 165F. In one hour the temp went from 165F down to 153F. Again using only water. Clearly not good.

Now the most obvious question is, does the lack of grain in the cooler speed the drop in temp? I assume the grain itself would help act as insulation and help retain that heat. But by how much?

If not, not sure what else I can do. I did not cover it with a blanket. That might help a couple degrees. The outside weather here today is fine, 68F. I've read people have tried to insulate the lid with spray foam insulation. Maybe I can try that.

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Put a layer of aluminum foil on the top of the mash before closing up the lid. You'll be amazed how well the heat stays in with this trick. Sometimes my end-of-mash temps are a half-degree higher than before I closed the lid. "Uh...what? How the hell did THAT happen?"

So I had some free time this morning and decided to see how adding strike water first works. I didn't add any grain, I was just testing to see what temps I need to strike/pre-heat the tun with so this weekend I can be in the ballpark. My tun was around 60 (should have taken exact temp) and my strike water was 2.56g at 185 (meant for a 5g batch, 8.20 lbs grain at 1.25 qt/lb). It dropped to 166 after 1.5 min and down to 163 in 4.5 min. Looks like I need to go higher. I'm going to try this a few more times for more data.