Can't Maintain Mash Temps

[FensterBos]

I converted an 52 qt. igloo cooler for my mash tun. I do a very good job at hitting my target temperature for my mash, but for some reason, even when my mash tun is in a 66 F degree environment, I am unable to keep it near my target temperature for longer than 30 to 40 minutes.
For instance, for a temp. target of 152 F I'll heat the water to 162-164 F; in the initial stages of my mash I will be on or near the 152 mark, but around 40 minutes to 60 minutes my mash temp will drop under 150 F. I'll add some water at 210 F, but that only increases the temperature for only a few moments.
I just did an iodine test and I am not confident that my starches have been 100% converted. Are there any steps I can take that won't dilute my batch? Should I drain half of the wort out, heat it up in my kettle to 168 F, and then pour it back into my mash for a longer period?
Thanks for the help!

 

[danorocks17]

have you tried wrapping a heavy blanket or old comforter around it? my chest cooler can leak some steam around the lid, so I cover it with an old heavy blanket, I lose, at the most, a degree over 60 min

 

[phenry]

Are you opening your cooler a lot? That could have a hand in your temps dropping. Also, how are you measuring the temp? I use a floating thermometer in my MLT and I have to stir the mash well before even thinking about checking the thermometer or it will always be off.

Are you preheating your tun? Just dumping in strike water at your target temp will always net you a lower mash temp than expected, the cooler will absorb a fair of that heat initially.

 

[GoldMiner]

Do you preheat your mash tun?

I usually heat my strike water to 170 F and add it to the empty tun.

Wait a few minutes and add the grain when the temp hits 161-162 F for my normal target of 150 F.

I use a 60 qt Igloo cooler and usually lose 1-2 degrees over the hour mash.

 

[danorocks17]

Are you preheating your tun?

+1, definitely need to preheat the tun

 

[FensterBos]

I need to open the top to stir, so I do lose some heat that way. But I do preheat the cooler beforehand with hot tap water. I used to use a digital themo, but the battery is dead; I've been using the standard glass thermo that comes with a beginner kit.
What is the best solution to raise mash temps without diluting the wort with more water? Should I drain our wort, heat it up, and then put it back in the mash tun for another 20 minutes?

 

[phenry]

I need to open the top to stir, so I do lose some heat that way. But I do preheat the cooler beforehand with hot tap water. I used to use a digital themo, but the battery is dead; I've been using the standard glass thermo that comes with a beginner kit.
What is the best solution to raise mash temps without diluting the wort with more water? Should I drain our wort, heat it up, and then put it back in the mash tun for another 20 minutes?

How often are you stirring? I only stir when I initially dump my grain in and when I check what the temperature has stabilized at 5 minutes later. Then I don't touch it until I'm about to start vorlaufing. The enzymes know what they're doing, they'll find the starches on their own.

 

[danorocks17]

But I do preheat the cooler beforehand with hot tap water.

I don't know if my way is the best way, but what I do is figure out what my strike water temp should be then heat it up to 3-4 degrees higher and pour all my strike water in my tun and let that sit for 10-15 minutes, then I mash it and make sure my temp is where it needs to be.

 

[Yooper]

Do you preheat your mash tun?

I usually heat my strike water to 170 F and add it to the empty tun.

Wait a few minutes and add the grain when the temp hits 161-162 F for my normal target of 150 F.

I use a 60 qt Igloo cooler and usually lose 1-2 degrees over the hour mash.

I actually use 180 degree water to preheat my MLT in my cold climate! I add 180 degree water and the cooler immediately sucks out tons of heat! Within 15 minutes it slows and stabilizes, and then I can stir until it lowers to my strike temp. It usually is 166 degrees or so by then. That's how much heat that cooler "sucks" out! But then it drops less than one degree over an hour.

 

[FensterBos]

Sounds good. I'll heat up my strike water and let it cool in the tun and then add my grain.

 

[JonM]

Do you have lots of space between the top of the mash and the cooler lid?

 

[FensterBos]

It depends on the grain bill; sometimes a few inches, sometimes more.

 

[JonM]

It depends on the grain bill; sometimes a few inches, sometimes more.

I've had great results with cutting out some discs of 3/4 inch styrofoam the same ID as the inside of the mash tun, placing them in a heat resistant crock-pot liner bag, and resting it right on top of the mash.

 

[JonM]

I've had great results with cutting out some discs of 3/4 inch styrofoam the same ID as the inside of the mash tun, placing them in a heat resistant crock-pot liner bag, and resting it right on top of the mash.

I mean - the same diameter as the ID of the mash tun.

 

[kappclark]

I actually use 180 degree water to preheat my MLT in my cold climate! I add 180 degree water and the cooler immediately sucks out tons of heat! .

YES= I mash in the basement, and it took me several batches to figure out that I needed 180 deg approx to start if I wanted to have any shot at hitting 153 - 156 with 10lbs of grain...the thermal mass of both the cooler and the grain have a definite effect..once I am dialed in, the rubbermaid cooler does fine maintaining temps..

 

[BWN]

I usually add about 2 qts of boiling water or near boiling water to my cooler and let it sit for about 5 minutes. I drain it all out then add my strike water at whatever temperature that I need to usually about 164 to 166.

 

[Just_brew]

Oh yes, the inevitable loss of temp using a cooler. This happens a lot and it is very difficult to achieve a steady temp for over 60 min. How I have worked around this is to shoot for a temp slightly higher than the temp you are trying to achieve to compensate for the heat loss. I also preheat my cooler as well. -This does not always happen due to the wise words of Charlie Papazian that have helped me get through the worries of home brewing, "Relax, Don't worry, Have a Homebrew"- I use a 15 gallon cooler as a mash tun, I find a larger grist helps to alleviate heat loss as well. A few degrees in temp loss is nothing to the enzymes that are doing the conversion of starches. If it was 5 or more I would worry but 1 or 2 is no big deal. You could always step mash to 160 F if you are so worried. I have found that pulling wert from the tun can produce off flavors when heated to a higher temp in order to raise the temp of your mash a few degrees. You are loosing more of the magic process than you are gaining.
So my advice is to crack another beer, read some more while you are waiting on conversion. A few extra minutes is not going to hurt anything. Besides if you are using different types of adjuncts in your mash, that will also effect the rate of starch conversion. Wheat is a pain in the butt and so are oats, rice not so bad. Hope I helped.
Cheers!
J.Brewer:rockin:

 

[weirdboy]

I have found that pulling wert from the tun can produce off flavors when heated to a higher temp in order to raise the temp of your mash a few degrees. You are loosing more of the magic process than you are gaining.

Someone better tell the Germans and Czechs they are doing it wrong. Granted, they pull out the thick mash....

 

[CidahMastah]

Someone better tell the Germans and Czechs they are doing it wrong. Granted, they pull out the thick mash....

+1

Decoctions haven't been known for producing "off flavors", though rumored to give more malt character. I think just brew might have been off the mark with his comment.

 

[Just_brew]

I see both of you miss read my message. So I will copy and paste this to both. When you pull wert from your tun and heat it you are putting the enzymes in that state of suspension, so the actual process of starch conversion is halted momentarily. When adding the higher temp wert to an already homogenize grist, you run the risk of extracting tannins from the top of your grain bed. This process is very different from the decoction method used with unmodified grains. A percentage of the grist is removed and brought to a boil to aid with breaking down of the unmodified grain. Usually using highly modified grains, a decoction is not necessary in the production of starches, although it can aid in head retention and body of the final product. So I will state this one more time, it is not recommended that you pull wert from your mash tun and heat to a high temperature to gain only few degrees in your mash. Tannins can be extracted in the process producing an off flavor. So please, if you are going to stick your foot in your mouth and state that I have missed the mark, try to understand what I was saying before you comment. This will save a lot of time and humiliation on both ends.
Cheer!
J.Brewer

 

[CidahMastah]

I see both of you miss read my message. So I will copy and paste this to both. When you pull wert from your tun and heat it you are putting the enzymes in that state of suspension, so the actual process of starch conversion is halted momentarily. When adding the higher temp wert to an already homogenize grist, you run the risk of extracting tannins from the top of your grain bed. This process is very different from the decoction method used with unmodified grains. A percentage of the grist is removed and brought to a boil to aid with breaking down of the unmodified grain. Usually using highly modified grains, a decoction is not necessary in the production of starches, although it can aid in head retention and body of the final product. So I will state this one more time, it is not recommended that you pull wert from your mash tun and heat to a high temperature to gain only few degrees in your mash. Tannins can be extracted in the process producing an off flavor. So please, if you are going to stick your foot in your mouth and state that I have missed the mark, try to understand what I was saying before you comment. This will save a lot of time and humiliation on both ends.
Cheer!
J.Brewer

I have read that most of the conversion in today's highly modified malts is complete in the first 15 minutes. So if you give your mash at least 15 minutes at your mash temp you likely have converted the vast majority of the starches. Not sure how bad you would hurt your mash efficiency if you pulled some wort and stopped the conversion of starches by heating and adding back in because they are already converted for the most part. As with a decoction this process may actually to lead to a few more points towards efficiency.

You don't run the risk of tannin extraction unless you have a basic PH AND high temp wort. If you are just heating the wort and adding it back you are not making it more basic since you aren't thinning the wort with more water. (advice: remove foot from mouth)

Not sure why you would want to pull wort and heat it to increase your mash temp anyway - point is I still disagree with you. It is highly unlikely you would have any issues as you are alluding to based on the process you are describing.

People doing decoctions these days still do them with modern malts. The main reasons are to improve color and increase the malty aspect of the lager/ hefe, etc. The color does appear to change, but the flavor attribute is debatable and contested by various brewers. I am actually in the midst of doing a series of lagers to test the effects myself to see if I can discern them.

 

[Just_brew]

You do run the risk of pulling tannins, I have done this, and learning from ones mistakes is one of the joys of homebrewing. "You don't run the risk of tannin extraction unless you have a basic PH AND high temp wort. If you are just heating the wort and adding it back you are not making it more basic since you aren't thinning the wort with more water. (advice: remove foot from mouth)" If you are heating the wert to a temperature that will effect the whole grist, you have to damn near bring it to a boil, thus loosing water to evaporation which condenses your wert cause a swing in PH. So this is why I advise against it and yes you will pull tannins. Plus on a side not: The OP probably is not testing for PH anyway, so the advise to not pull and heat his/her wert to increase mash tun temp. is advised. So when you are done chewing on my foot I would like it back.
Cheers!! LOL
J.Brewer

 

[CidahMastah]

:fro:

You do run the risk of pulling tannins, I have done this, and learning from ones mistakes is one of the joys of homebrewing. "You don't run the risk of tannin extraction unless you have a basic PH AND high temp wort. If you are just heating the wort and adding it back you are not making it more basic since you aren't thinning the wort with more water. (advice: remove foot from mouth)" If you are heating the wert to a temperature that will effect the whole grist, you have to damn near bring it to a boil, thus loosing water to evaporation which condenses your wert cause a swing in PH. So this is why I advise against it and yes you will pull tannins. Plus on a side not: The OP probably is not testing for PH anyway, so the advise to not pull and heat his/her wert to increase mash tun temp. is advised. So when you are done chewing on my foot I would like it back.
Cheers!! LOL
J.Brewer

You crack me up. I think it is funny you get your panties all up in a bunch when someone has an opinion different from your own - so you resort to online tough guy stuff (stellar way to introduce yourself to the HBT forums days into your joining)

Still disagree and think you had something else happen with your brew. If you boil it "WORT", not "WERT" it would make the PH marginally more acidic not basic (I have read that tannin extraction is most often noted when a PH greater than 6 so boiling the wort will not put you at risk for tannin extraction). You shouldn't run any risk of tannin extracting from the grain husks. You probably made another mistake that lead to off flavors that you are calling tannin extraction.

One thing we agree on is that there are better ways to increase the mash temp than extracting work and boiling and returning to the pot. Beyond that you are just running your mouth and spreading misinformation.

I do love me some brew talk banter !

 

[weirdboy]

I see both of you miss read my message. So I will copy and paste this to both. When you pull wert from your tun and heat it you are putting the enzymes in that state of suspension, so the actual process of starch conversion is halted momentarily.

If you are doing a proper decoction, you briefly (say, 15 minutes) raise the decocted portion to your saccharification temperature for conversion. Then you continue heating it to a boil which denatures the enzymes. It does not "suspend" enzyme activity, it completely stops it. Luckily, there are plenty of enzymes left in the mash tun.

When adding the higher temp wert to an already homogenize grist, you run the risk of extracting tannins from the top of your grain bed. This process is very different from the decoction method used with unmodified grains.

Please explain how it is different, exactly. How do you get the decocted portion of your mash back into your mash tun after boiling?

Also you might want to look into a little decoction step known as a "mash-out" decoction, where you draw off only liquid wort and bring it to a boil to bring the mash up to mash-out temperatures.


Anyway the point being that if adding boiling hot stuff back into the mash tun resulted in all these tannins, I'm pretty sure the you'd be able to notice it in your favorite doppelbock.

 

[Just_brew]

LOL, no, not tough guy, and I like to use the word wert, I read it in an old german recipe book, so I have tried to keep it alive. I am also very opinionated when it comes these things, and you started it. LOL I have tested this a few times in small batches. Seem to play some role in off flavor, the only thing I could pin it on was tannin esters. I would still like my foot back when you are done.

 

[weirdboy]

Why do you keep calling people tough guy?

EDIT: nevermind, I mis-read your post

 

[CidahMastah]

the only thing I could pin it on was tannin esters.

... tannin esters? Must be some more brewing terminology the German's made up that I am not aware of.

Wise man once said. First thing to do when you to do when you are digging yourself into a hole is: stop digging.

If what you said is true about tannins,... decocted lagers, hefe's etc. would be tannin ridden. Germans have been known for this type of lager with decoctions to achieve stepped rests. There are no tannins in those styles. Not sure why you continue to push the issue when you clearly don't have a leg to stand on.

4 posts in and you apparently know it all...

 

[Bishop916]

Misinformation is always bad, but then again post count has nothing to do with overall expertise. Maybe he is from another site, or never bothered to post on brewing forums. You could take what he has to say with a grain of salt and use it as a starting point to research his position. No need to lambast the guy.


Lesson to All: take basic advice here, it can be useful, but always do what you can to research on your own regarding process fundamentals.

- B916

 

[CidahMastah]

bishop916 - I hear what you are saying. Maybe I shouldn't have. But the fact of the matter is I made a comment that wasn't harsh in nature and he started off with stating I (we) were putting our foot in our mouths. Not saying he isn't experienced, but he is new to the forum and being well... kinda snarky. So shame on me.

I believe that anecdotal experience is what makes the forums great too. I do also believe that there is no need to troll and try to flame people up, which the OP clearly is doing.

 

[Bishop916]

Agreed.
Also, to answer the topic, I used this last night, real-time, while mash was in, to correct some temp issues I was having - worked like a charm!

Brew365's Mash Sparge Water Calculator

On another note;

"Nice to meet ya' CidahMastah!"

*shakes hand*

 

[CidahMastah]

Agreed.

On another note;

"Nice to meet ya' CidahMastah!"

*shakes hand*

You too bishop Have seen you around on this thing for a while now. Pleasure to make your acquaintance!

 

[NorthBayBrewer]

Not sure if this applies in your situation, but do not let the thermometer touch the sides or bottom of your cooler during the reading, it will read too cool. A good insulator will not allow for a lot of heat transfer between the hot mash and the outside. I use a 10 gal Home Depot.

Here is what I do: I never preheat, just dump in the water then the grains. Then I mash in for a minute, then take a reading. Stir the thermometer around a bit, make sure you are not in a hot/cold patch. Once I think the temp is satisfied, I close the lid and walk away for 60. I used to stir more frequently, but I have had my best results with a set-it and forget it approach.

Good Luck