Mash tun temp with grains

[darby_ross]

I just got a new 10 gallon rubbermaid round mash tun and wanted to do a practice run with just water. I put 4.5 gallons in at 163 and let it sit for an hour. I lost 6 degrees on the first run and 5 degrees on the 2nd run. My question is if there are grains in the mash tun will that decrease my temp loss or I'm I just stuck with crappy mash tun?

 

[AnOldUR]

You need to pre-heat the MLT. Put your water in the tun hotter than your strike temperature and stir with the lid off until it settles at the proper temperature. At this point, put the lid on and start timing. This is when you'd add your grain.

 

[darby_ross]

I preheated the tun with boiled water and let it sit for 15 minutes before adding the other water and still had the temp loss.

 

[kombat]

The grain will indeed help you hold temperature slightly better, as you'll be increasing the thermal mass of the substance in the cooler. However you'll lose a little more heat initially, as the grains warm up to mash temperature from room temperature as you mix them in.

As AnOldUR suggested, pre-heating your mash tun with hot water will help minimize the heat loss during mashing. Other tactics are covering the grain bed with a sheet of aluminum foil, sealing the mash tun lid with cling wrap, and wrapping the mash tun in a warm covering such as a blanket or sleeping bag. However, most conversion happens within the first 15-30 minutes anyway, it's more important to dial in your system and hit your mash temperature as closely as possible initially. Losing 3-4 degrees over an hour is a non-issue.

 

[TungstenBeer]

I just got a new 10 gallon rubbermaid round mash tun and wanted to do a practice run with just water. I put 4.5 gallons in at 163 and let it sit for an hour. I lost 6 degrees on the first run and 5 degrees on the 2nd run. My question is if there are grains in the mash tun will that decrease my temp loss or I'm I just stuck with crappy mash tun?

I had the same problem (much to my surprise) when I started all grain brewing a couple years ago. I expected 1-2 degrees of temperature drop, and then BAM, it was 5 degrees in 25 minutes (it was probably 40F outside). This is ultimately why 3 months later I was using a cheap HERMS setup. The "temp won't drop more than a degree or two" was definitely a myth in my experience.

I did pre-heat my MLT every time too; didn't matter. After the first brew, I tried putting a piece of foil on the top of the grain bed, which definitely helped. I didn't try any of the other stuff mentioned above though.

 

[wilserbrewer]

I just got a new 10 gallon rubbermaid round mash tun and wanted to do a practice run with just water. I put 4.5 gallons in at 163 and let it sit for an hour. I lost 6 degrees on the first run and 5 degrees on the 2nd run. My question is if there are grains in the mash tun will that decrease my temp loss or I'm I just stuck with crappy mash tun?

Sorry, this test is meaningless IMO.

Firstly you need to preheat the cooler as stated ablove.

Secondly, a mash will behave much, much differently than water with regard to holding temps. Water will cool much faster.

The 10 gallon beverage coolers are documented to keep mash temps very well, RDWHWB

 

[DNKDUKE]

I have only experienced 1 to 2 degrees drop in an hour mash.
What I'm doing right, I don't know

 

[LandoLincoln]

I just got a new 10 gallon rubbermaid round mash tun and wanted to do a practice run with just water. I put 4.5 gallons in at 163 and let it sit for an hour. I lost 6 degrees on the first run and 5 degrees on the 2nd run. My question is if there are grains in the mash tun will that decrease my temp loss or I'm I just stuck with crappy mash tun?

There are some things that you can do to decrease the loss. The easiest thing I ever did was to put a layer of aluminum foil over the top of the grain bed. It's pretty amazing how much heat you lose if you have a large amount of deadspace in your mash tun. You can also put a strip of duck tape around the cooler lid. Throwing a sleeping bag over it helps as well.

 

[darby_ross]

I'm brewing this weekend so we'll see then.

 

[bja]

The "temp won't drop more than a degree or two" was definitely a myth in my experience.

You were doing it wrong. Mine has never lost more than 1 degree during a 60 minute mash.

 

[TungstenBeer]

You were doing it wrong. Mine has never lost more than 1 degree during a 60 minute mash.

I definitely did the first time; no denying that. After that, all I'm saying is I pre-heated every time and it didn't work out to ever be less than a 4 degree drop in an hour (which was my largest mash using an aluminum foil cover).

What the sticking point for me is, I think a lot of new brewers see generalizations like "use a cooler, it won't drop more than a degree or 2 and that's fine" and go that route... when in actuality "use a cooler and pre-heat it, cover the mash with foil, tape the top, wrap with a blanket, and [insert other helpful tip here]" is more of the reality.

So, rather than telling me my process was wrong and yours is right, it would help to offer up your process. It's a moot point for me now but it would certainly help others.

 

[Hacky2447]

I definitely did the first time; no denying that. After that, all I'm saying is I pre-heated every time and it didn't work out to ever be less than a 4 degree drop in an hour (which was my largest mash using an aluminum foil cover).

What the sticking point for me is, I think a lot of new brewers see generalizations like "use a cooler, it won't drop more than a degree or 2 and that's fine" and go that route... when in actuality "use a cooler and pre-heat it, cover the mash with foil, tape the top, wrap with a blanket, and [insert other helpful tip here]" is more of the reality.

So, rather than telling me my process was wrong and yours is right, it would help to offer up your process. It's a moot point for me now but it would certainly help others.

Ive been frustrated with this as well.

I set my Home Depot 10 gallon cooler up, preheat the mash tun with near boiling water, dump out the water and add my strike water. Still comes out about 1 to 2 degrees cooler than I want, So I just add about half a gallon of boiling water to get me where I need it.

During the mash I cover the mash tun with a couple blankets (comforters) and have a submersible temp probe in the mash tun.

I lose about 1.5 to 2 degrees in 30 mins. I just add a bit more boiling water and stir the crap out of it to reduce hot/cold spots to bring the temp back up and it holds fine for the duration of the mash.

I get full conversion in the 60 mins, and no stuck sparge.

 

[TungstenBeer]

Ive been frustrated with this as well.

I set my Home Depot 10 gallon cooler up, preheat the mash tun with near boiling water, dump out the water and add my strike water. Still comes out about 1 to 2 degrees cooler than I want, So I just add about half a gallon of boiling water to get me where I need it.

During the mash I cover the mash tun with a couple blankets (comforters) and have a submersible temp probe in the mash tun.

I lose about 1.5 to 2 degrees in 30 mins. I just add a bit more boiling water and stir the crap out of it to reduce hot/cold spots to bring the temp back up and it holds fine for the duration of the mash.

I get full conversion in the 60 mins, and no stuck sparge.

It's a great workaround. In my opinion, all new brewers using a cooler (ESPECIALLY doing 5 gallon batches in a 10 gallon cooler) should have a pot (maybe a gallon or so) of near-boiling water ready "just in case." This would have eliminated a lot of running back and forth to my kitchen back on my first brewday, haha.

 

[Hacky2447]

It's a great workaround. In my opinion, all new brewers using a cooler (ESPECIALLY doing 5 gallon batches in a 10 gallon cooler) should have a pot (maybe a gallon or so) of near-boiling water ready "just in case." This would have eliminated a lot of running back and forth to my kitchen back on my first brewday, haha.

Yeah buying upgraded equipment and having two burners with two pots makes thing SOOO much easier now.

I can just heat the strike water dough in while having a few gallons heating up in the second pot, then add what I need to let it mash at the temps I want. I can even ramp up form lower temps. Makes things fairly simple, but uses a lot f water doing it this way. Takes my 1.33 qt per LB to a higher ratio that needs to be calculated for later.

 

[bja]

I definitely did the first time; no denying that. After that, all I'm saying is I pre-heated every time and it didn't work out to ever be less than a 4 degree drop in an hour (which was my largest mash using an aluminum foil cover).

What the sticking point for me is, I think a lot of new brewers see generalizations like "use a cooler, it won't drop more than a degree or 2 and that's fine" and go that route... when in actuality "use a cooler and pre-heat it, cover the mash with foil, tape the top, wrap with a blanket, and [insert other helpful tip here]" is more of the reality.

So, rather than telling me my process was wrong and yours is right, it would help to offer up your process. It's a moot point for me now but it would certainly help others.

I never preheat the cooler. Beersmith tells me the strike temperature based on mash tun, and grain temperatures. It's perfect every time and like I said, it only loses 1 degree per hour, if that. No blanket, no foil, no tape.

I'm guessing that your strike temp was too low and you didn't stir the mash long enough to equalize the temperature, but without knowing what you did, I am only guessing.

 

[wilserbrewer]

I have noticed that it can take a good 5 minutes or so for the mash temp to equalize and fully absorb the temp of the cooler grain. What I believe may be happening to those that experience higher losses than others is that they dough in and take a temp immediately, before the mash temp has stabilized resulting in a false high temp measurement.

I dough in and take a temp, wait a few minutes, stir and take another temp that is typically 2-3 degrees lower and more truly represents your actual rest temp.

I also find it easier to overheat the strike water by about 10 degrees, allowing it to preheat the cooler and settle to strike temp, rather than using a separate addition to preheat.

 

[Hacky2447]

I have noticed that it can take a good 5 minutes or so for the mash temp to equalize and fully absorb the temp of the cooler grain. What I believe may be happening to those that experience higher losses than others is that they dough in and take a temp immediately, before the mash temp has stabilized resulting in a false high temp measurement.

I dough in and take a temp, wait a few minutes, stir and take another temp that is typically 2-3 degrees lower and more truly represents your actual rest temp.

I also find it easier to overheat the strike water by about 10 degrees, allowing it to preheat the cooler and settle to strike temp, rather than using a separate addition to preheat.

I am going to try this this weekend.

 

[cyberbrew]

I never preheat the cooler. Beersmith tells me the strike temperature based on mash tun, and grain temperatures. It's perfect every time and like I said, it only loses 1 degree per hour, if that. No blanket, no foil, no tape.

I'm guessing that your strike temp was too low and you didn't stir the mash long enough to equalize the temperature, but without knowing what you did, I am only guessing.

This ^^. Make sure your strike water is the right temp to begin with...for YOUR equipment. I adjusted my strike temp up by a couple degrees, after the first couple batches missed the temps I was looking for, and have been spot on since. That said, if you miss your temps you'll still make beer, and most likely good beer!

 

[AnOldUR]

I never preheat the cooler. Beersmith tells me the strike temperature based on mash tun, and grain temperatures. It's perfect every time and like I said, it only loses 1 degree per hour, if that. No blanket, no foil, no tape.

I'm guessing that your strike temp was too low and you didn't stir the mash long enough to equalize the temperature, but without knowing what you did, I am only guessing.

So, you're saying you mash in hotter than what's needed to compensate for the heat lost to the grain and then let your temperature stabilizes by waiting for your tun to heat up? Have to wonder how much conversion takes place at the higher temperature before your grain bed reaches your target temperature. Probably all of it. :cross:

 

[LandoLincoln]

So, you're saying you mash in hotter than what's needed to compensate for the heat lost to the grain and then let your temperature stabilizes by waiting for your tun to heat up? Have to wonder how much conversion takes place at the higher temperature before your grain bed reaches your target temperature. Probably all of it. :cross:

I've tried both ways: pre-heating the MLT and not pre-heating the MLT.

I've found that if I don't pre-heat the MLT then I had to add 17° to the strike temperature to hit my target mash temp, but if I did pre-heat the MLT then I had to add 15° to the strike temperature.

Bottom line: pre-heating the MLT doesn't do a whole lot, at least in my experience.

 

[bja]

Have to wonder how much conversion takes place at the higher temperature before your grain bed reaches your target temperature. Probably all of it. :cross:

Yeah, because we all know that complete conversion takes place in the first 2 minutes of the mash.

 

[AnOldUR]

Yeah, because we all know that complete conversion takes place in the first 2 minutes of the mash.

Yep. Just like we know that after two minutes the temperature of the tun stops dropping.

I realize that nobody ever exaggerates on the internet (I never do. :cross, but like other thing brewing, there is no right answer. On a hot summer day, your MLT might stabilize in a few minutes. Put hot water and grain in one that's been stored in an unheated garage in the winter and it could take 10 - 15 minutes.

To me it just made sense to wait until the temperature was stable before adding grain. Doesn't mean I was right.